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6,400 | Catheter ablation versus standard conventional treatment in patients with left ventricular dysfunction and atrial fibrillation (CASTLE-AF) - study design. | Electrical isolation of the pulmonary veins by catheter ablation is an emerging treatment modality for the treatment of atrial fibrillation (AF) and is increasingly used in patients with heart failure.</AbstractText>The catheter ablation versus standard conventional treatment in patients with left ventricular dysfunction and atrial fibrillation trial (CASTLE-AF) is a randomized evaluation of ablative treatment of atrial fibrillation in patients with left ventricular dysfunction. The primary endpoint is the composite of all-cause mortality or worsening of heart failure requiring unplanned hospitalization using a time to first event analysis. Secondary endpoints are all-cause mortality, cardiovascular mortality, cerebrovascular accidents, worsening of heart failure requiring unplanned hospitalization, unplanned hospitalization due to cardiovascular reason, all-cause hospitalization, quality of life, number of therapies (shock and antitachycardia pacing) delivered by the implantable cardioverter-defibrillator (ICD), time to first ICD therapy, number of device-detected ventricular tachycardia and ventricular fibrillation episodes, AF burden, AF free interval, left ventricular function, exercise tolerance, and percentage of right ventricular pacing. CASTLE-AF will randomize 420 patients for a minimum of 3 years at 48 sites in the United States, Europe, Australia, and South America.</AbstractText> |
6,401 | Catheter ablation of recurrent scar-related ventricular tachycardia using electroanatomical mapping and irrigated ablation technology: results of the prospective multicenter Euro-VT-study. | Ventricular tachycardia (VT) late after myocardial infarction is an important contributor to morbidity and mortality. This prospective multicenter study assessed the efficacy and safety of electroanatomical mapping in combination with open-saline irrigated ablation technology for ablation of chronic recurrent mappable and unmappable VT in remote myocardial infarction.</AbstractText>In 8 European institutions, 63 patients (89% males) were enrolled in the study. All patients had remote myocardial infarction and presented with a median number of 17 (range 1-380) VTs in the preceding 6 months. Incessant VT was present in 14 patients (22%). Left ventricular ejection fraction measured 30 +/- 13%. A mean of 3 VTs were targeted per patient and 22% of all patients had only unmappable VT. The mean follow-up period was 12 +/- 3 months. A total of 164 VTs were targeted during catheter ablation. Ablation was acutely successful in 51 patients (81%). One patient (1.5%) experienced a major complication with degeneration of VT into ventricular fibrillation necessitating cardiopulmonary resuscitation maneuvers. However, no death occurred acutely or within the first 30 days after catheter ablation. During the follow-up, 19 of the initially successful ablated patients (37%) and 31 of all ablated patients (49%) developed some type of VT recurrence.</AbstractText>The results of this multicenter study demonstrate the high acute success rate and a low complication rate of irrigated tip catheter ablation of all clinical relevant VTs in remote myocardial infarction. However, during the follow-up a relevant number of recurrences occurred.</AbstractText> |
6,402 | [Right ventricular cardiac failure in hospitalized patients with chronic obstructive pulmonary disease: prevalence and clinical and instrumental characteristics]. | The prevalence of right ventricular cardiac failure (CF) and its characteristics were analysed in 326 hospitalized elderly patients with chronic obstructive pulmonary disease (COPD) (average age 70+/-11 years). At admission right ventricular CF was diagnosed in 107 (33%) patients with COPD; its prevalence did not depend to sex but increased with age, especially among men. In patients with COPD right ventricular CF was associated with atrial fibrillation, anemia and obesity as well as a history of myocardial infarction. In patients with right ventricular CF dimensions of right ventricle and left atrium were significantly larger than those in patients without CF. Right ventricular CF was often associated with dilation of right atrium and pulmonary hypertension, especially with severe pulmonary hypertension. These data suggested that age (especially among men), pulmonary hypertension, atrial fibrillation, anemia, obesity and probably a history of myocardial infarction are risk factors for right ventricular CF in hospitalized elderly patients with COPD. |
6,403 | [Treatment of patients with long nocturnal asystoles and obstructive sleep apnea syndrome by creating continuous positive air pressure in the upper respiratory tract]. | To study prevalence of obstructive sleep apnea syndrome (OSAS) in patients with nocturnal asystoles, and assess therapeutic efficiency of constant positive air pressure (CPAP) applied to upper respiratory tract in this category of patients.</AbstractText>The study incorporated 37 patients (33 men and 4 women, average age 50+/-11 years) with nocturnal heart beat interruptions of over 3 seconds. Baseline examination revealed grade II-III arterial hypertension in 67.5%, coronary heart disease - in 19%, diabetes mellitus in 8% and no cardiovascular disease - in 5.5% of patients. Sinus rhythm was registered in 30 (81%) of patients, 7 (19%) patients had permanent atrial fibrillation. Causes of deteriorated cardiac conduction were as follows: sinoatrial blocks and sinoatrial arrests (n=18), grade II-III atrio ventricular block (n=10), combination of these forms of bradyarrhythmias (n=2) and block of conduction to ventricles in permanent atrial fibrillation (n=7). According to intra esophageal cardiac pacing, the function of sinus node and atrio ventricular conduction appeared to be undisturbed in all patients with sinus rhythm. All patients have undergone polysomnographic (PSG) examination. For patients with OSAS, an individual selection of therapeutic pressure was carried out using the CPAP apparatuses. CPAP therapy was considered effective against OSAS if normalization of apnea/hypopnea index (AHI) was observed.</AbstractText>OSAS was registered in 25 cases (68%) (mean AHI 54.9+/-28.7), 20 patients (80%) had severe grade of the syndrome. CPAP therapy appeared to be effective in all patients. At the background of treatment AHI decreased from 60.7 to 5.5 episodes per hour of sleep, mean oxygen saturation of arterial blood rose from 74 to 90%. Effect of CPAP therapy relative to cardiac conduction abnormalities was attained in all 19 patients with sinus rhythm and only in one patient with permanent atrial fibrillation.</AbstractText>OSAS was revealed in 68% of patients with nocturnal bradyarrhythmias. Individually selected therapy with constant positive pressure in patients with nocturnal asystoles and OSAS efficiently eliminated in sleep asystoles and made it possible to avoid pacemaker implantation in some patients.</AbstractText> |
6,404 | [Repetitive hospitalizations of patients with chronic heart failure according to data of one year follow-up study]. | Patients with chronic heart failure (CHF) represent a group with high risk of repetitive hospitalizations. In order to assess frequency of repetitive hospitalizations and elucidate their risk factors we included in this study 962 patients with stage IIA-III and functional class II-IV CHF hospitalized in a multiprofile hospital once or repeatedly during 1 year. Rate of rehospitalizations during 1 year was 59%. The following factors of risk of rehospitalizations were revealed: admission because of progression of CHF, history of myocardial infarction, atrial fibrillation, systolic left ventricular dysfunction, hyperuricemia, and hyperglycemia. |
6,405 | Neurotoxic and cardiotoxic effects of cocaine and ethanol. | Concurrent abuse of alcohol and cocaine results in the formation of cocaethylene, a powerful cocaine metabolite. Cocaethylene potentiates the direct cardiotoxic and indirect neurotoxic effects of cocaine or alcohol alone.</AbstractText>A 44-year-old female with history of cocaine and alcohol abuse presented with massive stroke in the emergency department. CT scan revealed extensive left internal carotid artery dissection extending into the left middle and anterior cerebral arteries resulting in a massive left hemispheric infarct, requiring urgent decompressive craniectomy. The patient had a stormy hospital course with multiple episodes of torsades de pointes in the first 4 days requiring aggressive management. She survived all events and was discharged to a nursing home with residual right hemiplegia and aphasia.</AbstractText>The combination of ethanol and cocaine has been associated with a significant increase in the incidence of neurological and cardiac emergencies including cerebral infarction, intracranial hemorrhage, myocardial infarction, cardiomyopathy, and cardiac arrhythmias. The alteration of cocaine pharmacokinetics and the formation of cocaethylene have been implicated, at least partially, in the increased toxicity of this drug combination.</AbstractText> |
6,406 | Burst stimulation improves hemodynamics during resuscitation after prolonged ventricular fibrillation. | Although return of spontaneous circulation (ROSC) is frequently achieved during resuscitation for sudden cardiac arrest, systolic blood pressure can then decrease, requiring additional myocardial support. Previous studies have shown that a series of 1-ms electrical pulses delivered through the defibrillation patches during ventricular fibrillation (VF) can stimulate the autonomic nervous system to increase myocardial function following defibrillation. We hypothesized that a similar series of electrical pulses could increase myocardial function and blood pressure during the early post-resuscitation period.</AbstractText>Six swine were studied that underwent 6-7 min. Each animal received 5, 10, 15, or 20 pulse packets consisting of 6 10 A, 1-ms pulses every 3-4 s in random order whenever systolic blood pressure became less than 50 mmHg. All four sets of pulse packets were delivered to each animal. Systolic blood pressure and cardiac function (left ventricular +dP/dt) were increased to pre-stimulation levels or above by all four sets of pulse packets. The increases were significantly greater for the longer than the shorter number of pulse packets. The mean+/-SD duration of the time that the systolic pressure remained above 50 mmHg following pulse delivery was 4.2+/-2.5 min.</AbstractText>Electrical stimulation during regular rhythm following prolonged VF and resuscitation can increase blood pressure and cardiac function to above prestimulation levels.</AbstractText> |
6,407 | Stress cardiomyopathy and arrhythmic storm in a 14-year-old boy. | Stress cardiomyopathy is a newly described reversible cardiomyopathy, characterized by transient cardiac dysfunction usually precipitated by intense emotional or physical stress. Apart from the classical apical ballooning syndrome (Takotsubo), it is now increasingly recognized that the spectrum of stress cardiomyopathies is quite wide, with significant individual variations in clinical and morphological pattern. Very recently, it has been suggested that, in young boys in stressful situations, atypical forms of stress cardiomyopathy could be associated with malignant arrhythmias. We describe the case of a 14-year-old boy, in whom stress cardiomyopathy with mid-ventricular ballooning started with an arrhythmic storm. |
6,408 | Undersensing of ventricular fibrillation due to interference between a pacemaker and defibrillator in the same patient. | Sensing in pacemakers (PMs) and implantable cardioverter defibrillators (ICDs) is crucial to normal device behaviour. Since both devices treat different arrhythmias, the technical approach to signal detection is also completely different. A PM has a fixed threshold of sensing, above which events are sensed and therapy of the device withheld. On the other hand, the defibrillator has a variable threshold of sensing to detect tachyarrhythmias, with sometimes very small and changing electrogram amplitudes. In this case report, we describe interference between a PM and an ICD caused by these differences in the detection of cardiac events, leading to undersensing of ventricular fibrillation at defibrillation threshold testing. |
6,409 | What have we learned about the contribution of autonomic nervous system to human arrhythmia? | Myocardial infarction results in denervation, followed by neural remodeling characterized by nerve sprouting and heterogeneous sympathetic hyperinnervation throughout the myocardium. There is an association between the density of sympathetic nerves and occurrence of cardiac arrhythmia in humans. Autonomic nerve recording in ambulatory dogs showed a close association between autonomic nerve activity and paroxysmal atrial and ventricular arrhythmias. Cryoablation of the stellate ganglion prevented paroxysmal atrial tachycardia and atrial fibrillation in canine models. Further studies are needed to determine if these same methods can be used to control atrial arrhythmias in humans. |
6,410 | Mechanisms and clinical management of inherited channelopathies: long QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, and short QT syndrome. | The following briefly reviews features and management of long QT syndrome (LQTS), Brugada Syndrome, catecholaminergic polymorphic ventricular tachycardia (CPVT), and short QT syndrome (SQTS). LQTS is marked by QT prolongation, syncope and sudden death due to torsades de pointes. Risk stratification is based on age, gender, history of symptoms, QT interval, and genetic subtype of LQTS. In addition to avoidance QT-prolonging drugs and high intensity sports, standard treatment for LQTS involves anti-adrenergic therapy, with implantable cardioverter-defibrillator (ICD) use in high risk subgroups. Brugada Syndrome is associated with right ventricular conduction delay and ST elevation in the right precordial leads, syncope, and sudden death from ventricular fibrillation. The electrocardiographic abnormality can be accentuated by sodium channel blocker, vagal stimulation or fever. Patients with aborted cardiac arrest and those with syncope and a spontaneous or sodium channel blocker-inducible type I Brugada ECG pattern are at high risk and should receive an ICD. The role of electrophysiologic testing is controversial. Although there is no reliable drug therapy for Brugada Syndrome, quinidine, which suppresses I(to) current, can reduce the incidence of arrhythmias. Patients with CPVT present with exercise-induced syncope and sudden cardiac death but normal resting electrocardiograms. Exercise or isoproterenol infusion may cause increased ventricular ectopy or bidirectional ventricular tachycardia. Treatment modalities include anti-adrenergic therapy and ICD implantation. Congenital SQTS is a relatively recently described disorder characterized by a very short QT interval and by susceptibility to atrial and ventricular fibrillation. ICD implantation is the primary therapy; quinidine may be a useful adjunctive therapy. |
6,411 | Predictors of ventricular tachycardia induction in syncopal patients with mild to moderate left ventricular dysfunction. | In patients with mild to moderate left ventricular dysfunction (LVD) (35% pound LVEF pound 50%) who present with syncope, demonstration of tachy and/or brady-arrhythmia has prognostic value. In this group of patients electrophysiological study (EPS) is often necessary.</AbstractText>A total of 53 consecutive patients with mild to moderate LVD and history of undetermined syncope underwent EPS. Sinus node function, His-Purkinje system conduction and ventricular electrical stability were evaluated.</AbstractText>Twenty eight patients (52.8%) had induction of sustained monomorphic ventricular tachycardia (VT) and five (9.4%) patients had a sustained ventricular arrhythmia other than monomorphic VT (ventricular flutter, ventricular fibrillation, and polymorphic VT) induced during EPS. Abnormal sinus node function and/or His-Purkinje system conduction was found in five (9.4%) patients. Age, gender, history of myocardial infarction, type of underlying heart disease and history of revascularization were not predictors of VT induction. Wide QRS morphology independently, and lower left ventricular ejection fraction and presence of pathologic q wave in precordial leads dependently, could increase risk of VT induction.</AbstractText>The EPS can determine which patient with syncope and mild to moderate LVD is likely to benefit from placing an ICD for prevention of sudden cardiac death. Pathologic precordial q wave, wide QRS morphology and lower left ventricular ejection fraction could be predictors of VT induction during EPS. Wide QRS morphology has an independent effect in this category.</AbstractText> |
6,412 | Repetitive endocardial focal discharges during ventricular fibrillation with prolonged global ischemia in isolated rabbit hearts. | Ventricular fibrillation (VF) during prolonged (>5 min) global ischemia (GI) could be due to repetitive endocardial focal discharges (REFDs). This hypothesis was tested in isolated rabbit hearts.</AbstractText>With optical mapping, simultaneous endocardial (left ventricle, LV) and epicardial (both ventricles) activations during VF with prolonged GI were studied (protocol I, 8 hearts). Lugol solution was applied to the LV endocardium in additional 5 hearts after 5-min GI (protocol II). During prolonged GI, sustained VF (>30 s) was successfully induced in 7 protocol I hearts. The dominant frequency of summed optical signals at the LV endocardium was higher than at the epicardium (P<0.05). Mapping data showed that after 5-min GI, REFDs were present in >90% for recording time. There were 18 windows of optical recording showing spontaneous VF termination. In 10, once REFDs ceased, the VF episode terminated immediately. Electrical defibrillation was also performed on 3 hearts. Eight shocks showed early VF recurrence after successful defibrillation. REFDs were consistently involved in the initiation period of recurrence. In protocol II, Lugol subendocardial ablation diminished REFD genesis during re-induced VF. These VF episodes were all non-sustained.</AbstractText>REFDs at the LV endocardium were important for both VF maintenance and post-shock recurrence during prolonged GI in this model.</AbstractText> |
6,413 | Ventricular fibrillation diagnosed with trans-thoracic echocardiography. | Electrocardiographic artifacts on scope are frequently observed in pre-hospital settings. They can lead to misdiagnosis or inappropriate resuscitation treatments. Here we report a case of ventricular fibrillation by electrical injury masked by ECG artifacts, after the savage of a victim, due to persistent 50Hz domestic current and identified by trans-thoracic ultrasonography. No clinical randomized studies define precisely the benefit of such an examination. In cases where ECG analysis is impossible due to artifacts, ultrasonographic exam could be useful to identify ventricular fibrillation. This case underlines also the need for a correct device ECG analysis in any circumstances. |
6,414 | [Malignant form of familial hypertrophic cardiomyopathy complicated with ventricular fibrillation in siblings. Electrocardiogram in hypertrophic cardiomyopathy - a review]. | A family with hypertrophic cardiomyopathy (HCM) (15-year-old boy, his 17-year-old sister and 45-year-old father) is described. The first sign of HCM was cardiac arrest (CA) due to ventricular fibrillation (VF) in a boy. A few months later sister of proband had the episode of CA due to VF. Both had implanted cardioverter-defibrillator (ICD). Echocardiography revealed HCM in both cases and in a father, who also received prophylactic ICD. During 24-month follow-up fast VT was observed in sister of proband. We review electrocardiographic changes in HCM and their correlation with magnetic resonance. |
6,415 | Atrial fibrillation is under-recognized in chronic heart failure: insights from a heart failure cohort treated with cardiac resynchronization therapy. | Atrial fibrillation (AF) is the most common sustained arrhythmia in patients with chronic heart failure (CHF). Under-detection of asymptomatic paroxysmal AF (PAF) underestimates the true burden of AF in patients with CHF. We retrospectively studied the prevalence of asymptomatic PAF in 162 CHF patients through analysis of cardiac resynchronization therapy (CRT) device downloads to determine whether these episodes are associated with adverse outcomes.</AbstractText>An episode of AF was defined by mode switching on CRT devices with an atrial rate >200 for at least 30 s. Of the 101 patients thought to be persistently in sinus rhythm (SR), 27% were found to have significant paroxysms of AF, with the cumulative percentage of time in the 'mode-switch mode' (i.e. the AF burden) of 1.6 +/- 0.9%. Mortality was 19.2% in patients with newly identified PAF with hospitalization and thrombo-embolism rates of 42.3 and 2.1%, respectively, compared with mortality of 10.4% with hospitalization and thrombo-embolism rates of 41.8 and 1.9%, respectively, in patients persistently in SR (P= NS).</AbstractText>Analysis of data from CRT devices in a population of CHF patients with severe left ventricular dysfunction shows that a significant proportion of those perceived to be persistently in SR have undiagnosed paroxysms of AF but with relatively low burden. These episodes appear to be associated with a trend towards increased mortality but no effects on hospitalization or thrombo-embolism rates.</AbstractText> |
6,416 | ACE I/D polymorphism associated with abnormal atrial and atrioventricular conduction in lone atrial fibrillation and structural heart disease: implications for electrical remodeling. | The angiotensin-converting enzyme (ACE) gene contains a common polymorphism based on the insertion (I) or deletion (D) of a 287-bp intronic DNA fragment. The D allele is associated with higher ACE activity and thus higher angiotensin II levels. Angiotensin II stimulates cardiac fibrosis and conduction heterogeneity.</AbstractText>The purpose of this study was to determine whether the ACE I/D polymorphism modulates cardiac electrophysiology.</AbstractText>Three different cohorts of patients were studied: 69 patients with paroxysmal lone atrial fibrillation (AF), 151 patients with structural heart disease and no history of AF, and 161 healthy subjects without cardiovascular disease or AF. Patients taking drugs that affect cardiac conduction were excluded from the study. ECG parameters during sinus rhythm were compared among the ACE I/D genotypes.</AbstractText>The ACE I/D polymorphism was associated with the PR interval and heart block in the lone AF cohort. In multivariable linear regression models, the D allele was associated with longer PR interval in the lone AF and heart disease cohorts (12.0-ms and 7.1-ms increase per D allele, respectively). P-wave duration showed a similar trend, with increase in PR interval across ACE I/D genotypes in the lone AF and heart disease cohorts.</AbstractText>The ACE D allele is associated with electrical remodeling in patients with lone AF and in those with heart disease, but not in control subjects. ACE activity may play a role in cardiac remodeling after the development of AF and heart disease.</AbstractText> |
6,417 | Cardiac signal extraction in patients with Implantable Cardioverter Defibrillators. | According to the guidelines the indication for Implantable Cardioverter Defibrillator (ICD) implantation is based on the ejection fraction. However, only a fraction of patients with implanted ICD shows live threatening arrhythmic events followed by adequate shocks. For this reason, further research is needed to find a more sensitive risk stratificator for patients prone to ventricular tachycardia or fibrillation. Unfortunately, standard prospective studies are time consuming. An alternative approach is to perform retrospective studies on patients with already implanted ICDs. So far, an implanted ICD is an exclusion criterion for Magnetic Field Imaging (MFI) studies. To overcome this problem several Blind Source Separation (BSS) algorithms have been tested to find out whether it is possible to separate the disturbances from the cardiac signals, in spite of the extreme difference in amplitude. Not all the methods are able to separate cardiac signal and disturbances. Temporal Decorrelation source Separation (TDSEP) is found to be superior both from a separation and performing point of view. For the first time it is possible to extract cardiac signals from measurements disturbed by an ICD, offering the possibility for a QRS-fragmentation analysis in patients with already implanted ICDs. |
6,418 | Use of real time three-dimensional transesophageal echocardiography in intracardiac catheter based interventions. | Real-time three-dimensional (RT3D) echocardiography is a recently developed technique that is being increasingly used in echocardiography laboratories. Over the past several years, improvements in transducer technologies have allowed development of a full matrix-array transducer that allows acquisition of pyramidal-shaped data sets. These data sets can be processed online and offline to allow accurate evaluation of cardiac structures, volumes, and mass. More recently, a transesophageal transducer with RT3D capabilities has been developed. This allows acquisition of high-quality RT3D images on transesophageal echocardiography (TEE). Percutaneous catheter-based procedures have gained growing acceptance in the cardiac procedural armamentarium. Advances in technology and technical skills allow increasingly complex procedures to be performed using a catheter-based approach, thus obviating the need for open-heart surgery.</AbstractText>The authors used RT3D TEE to guide 72 catheter-based cardiac interventions. The procedures included the occlusion of atrial septal defects or patent foramen ovales (n=25), percutaneous mitral valve repair (e-valve clipping; n=3), mitral balloon valvuloplasty for mitral stenosis (n=10), left atrial appendage obliteration (n=11), left atrial or pulmonary vein ablation for atrial fibrillation (n=5), percutaneous closures of prosthetic valve dehiscence (n=10), percutaneous aortic valve replacement (n=6), and percutaneous closures of ventricular septal defects (n=2). In this review, the authors describe their experience with this technique, the added value over multiplanar two-dimensional TEE, and the pitfalls that were encountered.</AbstractText>The main advantages found for the use RT3D TEE during catheter-based interventions were (1) the ability to visualize the entire lengths of intracardiac catheters, including the tips of all catheters and the balloons or devices they carry, along with a clear depiction of their positions in relation to other cardiac structures, and (2) the ability to ability to demonstrate certain structures in an "en face" view, which is not offered by any other currently available real-time imaging technique, enabling appreciation of the exact nature of the lesion that is undergoing intervention.</AbstractText>RT3D TEE is a powerful new imaging tool that may become the technique of choice and the standard of care for guidance of selected percutaneous catheter-based procedures.</AbstractText> |
6,419 | P wave and QT changes among inpatients with schizophrenia after parenteral ziprasidone administration. | Although ziprasidone has been reported to cause ventricular arrhythmias, there have been no studies regarding the influence of ziprasidone on atrial conduction. Intraatrial and interatrial conduction time prolongation and inhomogeneous propagation of sinus impulses are indicated by P wave changes on surface electrocardiography. We aimed to evaluate proneness to atrial fibrillation after intramuscular ziprasidone in drug-free inpatients with schizophrenia.</AbstractText>We evaluated 11 eligible inpatients who were drug free for at least 4 weeks with a primary diagnosis of schizophrenia disorder and 11 healthy controls who were hospital staff members. Electrocardiography was performed at baseline and 1.5-2h after ziprasidone injection. A 12-lead surface electrocardiogram was obtained from each subject in the supine position at a paper speed of 50mm/s and 2mV/cm.</AbstractText>The changes between baseline and the period after parenteral ziprasidone administration in P-wave duration, P-wave dispersion, QTc, QTc(max), QTc(min), and QT dispersion variables were significant (p>0.05). The initial P-wave dispersion was significantly longer in patients than in healthy controls (p<0.05). There were no correlations between electrocardiography parameters and clinical severity scores or demographic variables in either group.</AbstractText>Intramuscular ziprasidone administration does not seem to influence atrial and ventricular electrical conduction in drug-free inpatients with schizophrenia. However, schizophrenia might affect atrial conduction resulting in atrial fibrillation, which may be a cause of some complications in inpatients with this schizophrenia.</AbstractText> |
6,420 | Combination therapy with digoxin and diltiazem controls ventricular rate in chronic atrial fibrillation in dogs better than digoxin or diltiazem monotherapy: a randomized crossover study in 18 dogs. | Atrial fibrillation (AF) with excessively high ventricular rates (VR) occurs in dogs with advanced heart disease. Rate control improves clinical signs in these patients. Optimal drug therapy and target VR remain poorly defined.</AbstractText>Digoxin-diltiazem combination therapy reduces VR more than either drug alone in dogs with high VR AF.</AbstractText>Eighteen client-owned dogs (>15 kg) with advanced heart disease, AF, and average VR on 24-hour Holter > 140 beats per minute (bpm).</AbstractText>After baseline Holter recording, dogs were randomized to digoxin or diltiazem monotherapy, or combination therapy. Repeat Holter evaluation was obtained after 2 weeks; dogs were then crossed over to the other arm (monotherapy or combination therapy) for 2 weeks and a third Holter was acquired. Twenty-four hour average VR, absolute and relative VR changes from baseline, and percent time spent within prespecified VR ranges (>140, 100-140, and <100 bpm) were compared. Correlations between serum drug concentrations and VR were examined.</AbstractText>Digoxin (median, 164 bpm) and diltiazem (median, 158 bpm) decreased VR from baseline (median, 194 bpm) less than the digoxin-diltiazem combination (median, 126 bpm) (P < .008 for each comparison). With digoxin-diltiazem, VR remained <140 bpm for 85% of the recording period, but remained >140 bpm for 88% of the recording period with either monotherapy. Serum drug concentrations did not correlate with VR.</AbstractText>At the dosages used in this study, digoxin-diltiazem combination therapy provided a greater rate control than either drug alone in dogs with AF.</AbstractText> |
6,421 | Epicardially Based Pulmonary Vein Isolation for the Treatment of Atrial Fibrillation Utilizing Laser Energy in the Pig Model. | <b>Purpose:</b> Atrial fibrillation is a common disease that increases the incidence of cerebrovascular embolic events and cardiac dysfunction. Foci for atrial fibrillation have been mapped and found to be for the most part located within the ostia of the pulmonary veins. Since 2002 microwave and radiofrequency energy sources have been used to create pulmonary vein isolation lesions. This abstract summarizes the safety and efficacy of performing vein isolation lesions with laser as the energy source. <b>Description:</b> The large pig model was utilized for creation of isolation lesions around the pulmonary veins. The Optimaze E360 Surgical Ablation Handpiece from Edwards Lifesciences was utilized, it contains a 4 centimeter diffusing diode laser (980nm). All six of the pig models tolerated the procedure with a 40-day normal post procedure growth pattern. <b>Evaluation:</b> Upon reoperation one pig developed ventricular fibrillation with resection of adhesions. All five remaining pigs were fully tested and demonstrated complete electrical isolation. Gross pathology revealed intact well defined ablation lesions with an otherwise completely normal cardiac structure. All lesions were fully transmural at each histological sectioned point. <b>Conclusions:</b> Laser technology in the form of the Optimaze E360 Surgical Ablation Handpiece from Edwards Lifesciences, is able to reliably and consistently produce well defined electrical isolation scars around the pulmonary veins. This device is also amenable to performing the isolation procedure using a minimally invasive approach. |
6,422 | The Autonomic Nervous System and Atrial Fibrillation:The Roles of Pulmonary Vein Isolation and Ganglionated Plexi Ablation. | After the sequential successes of catheter ablation for the treatment of pre-excitation syndromes (WPW), junctional reentry (AVNRT) atrial flutter (AFL) and ventricular arrhythmias, clinical electrophysiologists have focused on the myocardial basis of atrial fibrillation (AF). Thus, the strategy for ablation of drug and cardioversion refractory AF was to isolate the myocardial connections from the focal firing pulmonary veins (PVs) in addition to altering the atrial substrate maintaining AF. However, the overall success rates have not achieved those of the other types of ablation procedures. In this review we have summarized the favorable aspects and drawbacks of pulmonary vein isolation (PVI). As for the role of the Intrinsic Cardiac Autonomic Nervous System (ICANS), both basic and clinical evidence has shown that ganglionated plexi (GP) stimulation promotes initiation and maintenance of AF, and that GP ablation reduces recurrence of AF following catheter or surgical ablation of these structures. Based on these findings, the GP Hyperactivity Hypothesis has been proposed to explain, at least in part, the mechanistic basis for the focal form of AF. For example, PV isolation may not always be necessary for elimination of AF, as in the early stages of paroxysmal AF. GP ablation alone, in these cases, may suffice for focal AF termination. In the persistent and long standing persistent forms the substrate for AF may be more extensive and therefore require GP ablation plus PV isolation and/or CFAE ablations. Clinical reports, both catheter based as well as minimally invasive surgical procedures, which include PVI plus GP ablation have shown relatively long-term success rates much closer to or equal to those achieved by myocardial ablation procedures in patients with WPW, AVNRT and AFL. |
6,423 | Use of automated external defibrillator in Peruvian out-of-hospital environment: improving emergency response in Latin America. | This case report relates out-of-hospital care to a patient with risk factors treated in the out-of-hospital services after cardiac arrest and ventricular fibrillation. The patient was treated according to the standards of basic life support and advanced cardiovascular life support; by applying an automated external defibrillator (AED) with favorable outcome and successful recovery of the patient from his risk of life condition. This is the first documented report with a favorable outcome in Peru, in out-of-hospital services and stresses the desirability of adopting policies for public access to early defibrillation. |
6,424 | [Role of hyperviscosity in cardiovascular and microvascular diseases]. | Blood viscosity plays a key role in regulating microvascular flow and alterations of hemorheological variables can lead to hyperviscosity, thus favoring the occurrence of occlusive thrombotic events. In the last few years an association between alterations in the hemorheologic profile and the severity of blood flow disturbances has been emphasized in several clinical and experimental conditions, possibly contributing to a better understanding of the pathophysiology of vascular disorders. The presence of alterations in hemorheological variables proved to be associated in several studies with an increased risk of cardiovascular disease and a higher mortality. The role of blood viscosity has also been analyzed in retrospective studies, which demonstrated that alterations in some hemorheological variables may increase the incidence of embolic events in patients with atrial fibrillation and may influence the responsiveness to antiplatelet drugs in patients with acute coronary syndromes. Recently, alterations of some hemorheological parameters were shown to be associated with complete occlusion of coronary arteries, favoring the occurrence of myocardial infarction with ST-segment elevation. In patients with this clinical condition, an increase in blood viscosity and some of its determinants was associated with increased infarct size and worse acute left ventricular dysfunction. Finally, the results of some observational clinical studies have shown that alterations of hemorheological variables may help to explain the pathophysiological mechanisms of some clinical disorders in which microvascular damage has been demonstrated, such as idiopathic sudden sensorineural hearing loss, retinal vein occlusion, and systemic sclerosis. |
6,425 | Predictors of adverse neurological outcome following cardiac surgery. | Stroke is a debilitating complication of cardiac surgery. Many intraoperative and postoperative factors predict the likelihood of post-cardiac surgery stroke. We evaluated preoperative parameters, seeking correlations with adverse neurological outcome following cardiac surgery. We investigated the possibility of preoperative carotid ultrasonography to select patients for carotid endarterectomy pre- or intraoperatively.</AbstractText>We conducted a retrospective analysis of 61 patients who suffered stroke post-cardiac surgery from 2003 to 2006. Data was collected for patient and disease characteristics, preoperative status, intraoperative events and postoperative course. Postoperative neurological complications were subdivided into three groups: mild/temporary events, moderate events such as seizures, and severe events such as stroke. A mild/temporary event was defined as a focal neurological deficit of less than 24 hours in duration.</AbstractText>A total of 2,226 cardiac cases were retrospectively evaluated. The frequency of stroke was 61 patients (2.7 percent). The mean age of these patients was 63.7 +/- 7.4 years, and 40 (65.6 percent) were males. Logistic EuroSCORE, left ventricular ejection fraction (as determined by two-dimensional echocardiogram) and aortic cross-clamp time were significantly correlated with postoperative neurological complications, with a p-value of less than 0.05 for all subgroups. There was a significant correlation between the presence of preoperative carotid disease (as proven by pre- and postoperative carotid ultrasonography) and postoperative neurological events (p-value equals 0.033). However, atrial fibrillation did not correlate with postoperative stroke.</AbstractText>The stage of cardiac disease (risk factor level, ejection fraction and presence of carotid stenosis) correlates with stroke and may predict an adverse neurological outcome.</AbstractText> |
6,426 | Characteristics and outcomes of hospitalized patients with heart failure and reduced vs preserved ejection fraction. Report from the Japanese Cardiac Registry of Heart Failure in Cardiology (JCARE-CARD). | Heart failure (HF) with preserved ejection fraction (EF) is common. We compared the characteristics, treatments, and outcomes in HF patients with reduced vs preserved EF by using the national registry database in Japan.</AbstractText>The Japanese Cardiac Registry of Heart Failure in Cardiology (JCARE-CARD) is a prospective observational study in a broad sample of patients hospitalized with worsening HF. The study enrolled 2,675 patients from 164 hospitals with an average of 2.4 years of follow-up. Patients with preserved EF (EF >or=50% by echocardiography; n=429) were more likely to be older, female, have hypertension and atrial fibrillation, and less likely to have ischemic etiology compared with those with reduced EF (EF <40%; n=985). Unadjusted risk of in-hospital mortality (6.5% vs 3.9%; P=0.03) and post-discharge mortality (22.7% vs 17.8%; P=0.058) was slightly higher in patients with preserved EF, which, however, were not different after multivariable adjustment. Patients with preserved EF had similar rehospitalization rates (36.2% vs 33.4%; P=0.515) compared with patients with reduced EF.</AbstractText>HF patients with preserved EF had a similar mortality risk and equally high rates of rehospitalization as those with reduced EF. Effective management strategies are critically needed to be established for this type of HF.</AbstractText> |
6,427 | Left ventricle radio-frequency ablation in the rat: a new model of heart failure due to myocardial infarction homogeneous in size and low in mortality. | The purpose of the current study was to create a model of myocardial infarction (MI) that is homogeneous in size with a low immediate (24 hours) mortality.</AbstractText>Male and female rats (n = 256) underwent left ventricle (LV) ablation (Ab) by a radiofrequency current (1000 kHz; 12 watts for 12 seconds) to promote a MI. A transmural MI occurred in all rats. Post-Ab complex arrhythmias were frequent (atrioventricular block, ventricular tachycardia, and fibrillation), which rapidly and spontaneously reverted to sinus rhythm. Among 66 male rats, immediate mortality occurred in 7.5%. Small MI size dispersion was characterized by smaller variability following Ab (x +/- SD: 45 +/- 8%) when compared with coronary occlusion (Oc; 40 +/- 19%). The histopathologic evaluations identified lesions similar to those which occurred following Oc, with scarring complete at 4 weeks. The hemodynamic and Doppler echocardiograms showed comparable increases in LV dimension, end-diastolic pressure, and pulmonary water content 1 and 4 weeks post-MI. Papillary muscle mechanics 6 weeks post-MI had matched inotropic and lusitropic dysfunction.</AbstractText>LV Ab gave rise to a MI within a narrow size limit and with a low immediate mortality. LV Ab resulted in histopathologic evolution, ventricular dilation, and dysfunction, impairment in myocardial mechanics, and congestive outcome that reproduced a MI from Oc.</AbstractText> |
6,428 | Magnetic resonance imaging at 1.5-T in patients with implantable cardioverter-defibrillators. | Our aim was to establish and evaluate a strategy for safe performance of magnetic resonance imaging (MRI) at 1.5-T in patients with implantable cardioverter-defibrillators (ICDs).</AbstractText>Expanding indications for ICD placement and MRI becoming the imaging modality of choice for many indications has created a growing demand for MRI in ICD patients, which is still considered an absolute contraindication.</AbstractText>Non-pacemaker-dependent ICD patients with a clinical need for MRI were included in the study. To minimize radiofrequency-related lead heating, the specific absorption rate was limited to 2 W/kg. ICDs were reprogrammed pre-MRI to avoid competitive pacing and potential pro-arrhythmia: 1) the lower rate limit was programmed as low as reasonably achievable; and 2) arrhythmia detection was programmed on, but therapy delivery was programmed off. Patients were monitored using electrocardiography and pulse oximetry. All ICDs were interrogated before and after the MRI examination and after 3 months, including measurement of pacing capture threshold, lead impedance, battery voltage, and serum troponin I.</AbstractText>Eighteen ICD patients underwent a total of 18 MRI examinations at 1.5-T; all examinations were completed safely. All ICDs could be interrogated and reprogrammed normally post-MRI. No significant changes of pacing capture threshold, lead impedance, and serum troponin I were observed. Battery voltage decreased significantly from pre- to post-MRI. In 2 MRI examinations, oversensing of radiofrequency noise as ventricular fibrillation occurred. However, no attempt at therapy delivery was made.</AbstractText>MRI of non-pacemaker-dependent ICD patients can be performed with an acceptable risk/benefit ratio under controlled conditions by taking both MRI- and pacemaker-related precautions. (Implantable Cardioverter Defibrillators and Magnetic Resonance Imaging of the Heart at 1.5-Tesla; NCT00356239).</AbstractText> |
6,429 | Long-term follow-up of idiopathic ventricular fibrillation ablation: a multicenter study. | This multicenter study sought to evaluate the long-term follow-up of patients ablated for idiopathic ventricular fibrillation (VF).</AbstractText>Catheter ablation of idiopathic VF that targets ventricular premature beat (VPB) triggers has been shown to prevent VF recurrences on short-term follow-up.</AbstractText>From January 2000, 38 consecutive patients from 6 different centers underwent ablation of primary idiopathic VF initiated by short coupled VPB. All patients had experienced at least 1 documented VF, with 87% having experienced > or =2 VF episodes in the preceding year. Catheter ablation was guided by activation mapping of VPBs or pace mapping during sinus rhythm.</AbstractText>There were 38 patients (21 men) age 42 +/- 13 years, refractory to a median of 2 antiarrhythmic drugs. Triggering VPBs originated from the right (n = 16), the left (n = 14), or both (n = 3) Purkinje systems and from the myocardium (n = 5). During a median post-procedural follow-up of 63 months, 7 (18%) of 38 patients experienced VF recurrence at a median of 4 months. Five of these 7 patients underwent repeat ablation without VF recurrence. Survival free of VF was predicted only by transient bundle-branch block in the originating ventricle during the electrophysiological study (p < 0.0001). The number of significant events (confirmed VF or aborted sudden death) was reduced from 4 (interquartile range 3 to 9) before to 0 (interquartile range 0 to 4) after ablation (p = 0.01).</AbstractText>Ablation for idiopathic VF that targets short coupled VPB triggers is associated with a long-term freedom from VF recurrence.</AbstractText> |
6,430 | Cardiac function and the proinflammatory cytokine response after recovery from cardiac arrest in swine. | Increased levels of cytokines have been reported after resuscitation from cardiac arrest. We hypothesized that proinflammatory cytokines, released in response to ischemia/reperfusion, increase following resuscitation and play a role in post-cardiac arrest myocardial dysfunction. Ventricular fibrillation (VF) was induced by coronary occlusion in 20 swine. After 7 min of VF, resuscitation was performed as per guidelines. Plasma levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6 were measured 15 min after the start of resuscitation in all animals and at intervals of 6 h in resuscitated animals. Intravascular pressures and cardiac output (CO) were also recorded. TNF-alpha abruptly increased after resuscitation, peaking at 15 min following return of spontaneous circulation, and declined to baseline levels after 3 h. IL-1beta increased more slowly, reaching a maximum 2 h after reperfusion. IL-6 concentrations were not significantly different from control values at any time point. Males demonstrated greater elevations of TNF-alpha and IL-1beta than females. Stroke work was significantly depressed at all time points with a nadir at 15-30 min after reperfusion, corresponding to the peak TNF-alpha values. The anti-TNF-alpha antibody infliximab attenuated the decrease in myocardial function observed 30 min after reperfusion. TNF-alpha increases during recovery from cardiac arrest are associated with depression of left ventricle (LV) function. The effect of TNF-alpha can be attenuated by anti-TNF-alpha antibodies. |
6,431 | Review and management of the dental patient with Long QT syndrome (LQTS). | Long QT syndrome (LQTS) is a unique cardiovascular condition, with both congenital and acquired forms that afflict patients. These patients show a lengthening of the repolarization phase of the cardiac cycle, which can be best visualized on an electrocardiogram (ECG). The ECG changes can include QT interval (the time between the start of the Q wave and the end of the T wave, as seen on an ECG) and T wave abnormalities, as well as progression to torsades de pointes and ventricular fibrillation. The ECG changes are most commonly elicited by physical activity, emotional stress, and certain medications. This condition represents a challenge for the oral and maxillofacial surgeon. Patients with LQTS must receive proper medical management and a controlled and anxiety-free surgical environment. The purpose of this article was to present a review of LQTS and provide recommendations for effective surgical management. Additionally, a case report of a patient with LQTS, treated by one of the authors, has been included. |
6,432 | Electrophysiological characteristics associated with symptoms in pacemaker patients with paroxysmal atrial fibrillation. | The purpose of this study is to identify the electrophysiological factors affecting symptoms in paroxysmal atrial fibrillation (PAF) using patients with paroxysmal atrial fibrillation and pacemakers with advanced atrial fibrillation (AF) diagnostics.</AbstractText>Seventy-nine patients (age 71.0 +/- 8.2, 54.4% male) with symptomatic PAF and AF burden of 1% to 50% with DDDRP pacemakers implanted were assessed for 6 months. Patients recorded symptom onset and duration and these were correlated with device-derived electrophysiological data.</AbstractText>Of 2,638 AF episodes, 333 were symptomatic and 2,305 asymptomatic, with 194 non-atrial tachyarrhythmia symptomatic episodes giving a sensitivity of 12.6% and a positive predictive value of 63.2% for specific AF symptoms. Symptomatic AF episodes were 3.8 times more common diurnally than nocturnally (p < 0.001). Diurnally, symptomatic AF was significantly associated with a shorter AF cycle length (CL; p = 0.04), faster ventricular rate (p = 0.004), shorter PR interval (p < 0.001), faster preceding heart rate (p = 0.001) and increased early recurrence of AF (p < 0.04). Nocturnally, a significantly longer AF CL (p = 0.04) and PR interval (p < 0.001) prior to AF onset predicted symptomatic AF.</AbstractText>Symptoms in PAF are predicted by changes in AF episode duration, ventricular rate during AF, preceding sinus heart rate, AV nodal conduction and AF cycle length but not ventricular irregularity. Excess diurnal sympathetic tone and excess nocturnal vagal tone predispose to symptomatic PAF. These findings may have relevance for therapies for symptom control of PAF.</AbstractText> |
6,433 | HIV protease inhibitors induced prolongation of the QT Interval: electrophysiology and clinical implications. | In recent years, there have been considerable advancements in our understanding of the role of ionic channels in mediating cardiac repolarization. Advances in ion channel cloning have generated great interest in the diagnosis and understanding of electrophysiological processes involved in ventricular repolarization, particularly the QT interval prolongation and abnormal T- and T/U-wave morphology associated with torsades de pointes. Unfortunately, a number of drugs are being increasingly recognized to alter the repolarization and, thus, increase the propensity for various cardiac arrhythmias, especially polymorphic ventricular tachycardia, syncope, and even ventricular fibrillation and sudden death. Recently, HIV protease inhibitors have been shown to cause prolongation of ventricular repolarization. This review focuses on electrophysiological mechanisms underlying drug-induced QTc prolongation in relation to protease inhibitors and its clinical implications. |
6,434 | [Chaos and fractals and their applications in electrocardial signal research]. | Chaos and fractals are ubiquitous phenomena of nature. A system with fractal structure usually behaves chaos. As a complicated nonlinear dynamics system, heart has fractals structure and behaves as chaos. The deeper inherent mechanism of heart can be opened out when the chaos and fractals theory is utilized in the research of the electrical activity of heart. Generally a time series of a system was used for describing the status of the strange attractor of the system. The indices include Poincare plot, fractals dimension, Lyapunov exponent, entropy, scaling exponent, Hurst index and so on. In this article, the basic concepts and the methods of chaos and fractals were introduced firstly. Then the applications of chaos and fractals theories in the study of electrocardial signal were expounded with example of how they are used for ventricular fibrillation. |
6,435 | Long-term clinical outcome of mitral valve repair in asymptomatic severe mitral regurgitation. | To assess the long-term survival, the incidence of cardiac complications and the factors that predict outcome in asymptomatic patients with severe degenerative mitral regurgitation (MR) undergoing mitral valve repair.</AbstractText>Up to 143 asymptomatic patients (mean age 63+/-12 years) with severe degenerative MR who underwent mitral valve repair between 1990 and 2001 were subsequently followed up for a median of 8 years. The study population was subdivided into three subgroups: patients with left ventricular (LV) dysfunction and/or dilatation (n=18), patients with atrial fibrillation and/or pulmonary hypertension (n=44) and patients without MR-related complications (n=81).</AbstractText>For the patients, 10-year overall and cardiovascular survival was 82+/-4% and 90+/-3%. At 10 years, patients without preoperative MR-related complications had significantly better overall survival than patients with preoperative LV dysfunction and/or dilatation (89+/-4% vs 57+/-13%, log rank p=0.001). Patients without preoperative MR-related complications also tended to have a better 10-year overall and cardiovascular survival than patients with atrial fibrillation and/or pulmonary hypertension (overall survival of 79+/-8%), although this did not reach statistical significance (log rank p=0.17). Cox regression analysis identified the baseline left ventricular ejection fraction and age as the sole independent predictors of outcome.</AbstractText>Our data indicate that in asymptomatic patients with severe degenerative MR, mitral valve repair is associated with an excellent long-term prognosis. Nonetheless, the presence of preoperative MR-related complications, in particular LV dysfunction and/or dilatation, greatly attenuates the benefits of surgery. This suggests that mitral valve repair should be performed early, before any MR-related complications ensue.</AbstractText> |
6,436 | Comparison of pulmonary veins anatomy in patients with and without atrial fibrillation: analysis by multislice tomography. | A possible role of anomalies in number and insertion of pulmonary veins (PV) in initiating atrial fibrillation (AF) has been suggested. It has been shown as well that changes in anatomy of PVs such as enlargement may have an effect on arrhythmogenesis. The aim of the study was to compare anatomy of the left atrium (LA) and PVs in patients with AF and control subjects.</AbstractText>Eighty two patients were evaluated with 64-slice computed tomography (MSCT). Fifty one of them were referred to catheter ablation with history of highly symptomatic AF--AF(+) group. Thirty one control subjects had no history of AF and were referred to MSCT for noninvasive evaluation of different pathologies which finally were excluded--AF(-) group. Study groups did not differ in regard to age, sex, presence of hypertension and left ventricular systolic function. Diameters of PV ostia were measured in anterior-posterior (AP) and superior-inferior (SI) directions. Venous ostium index was calculated as a ratio between these measurements.</AbstractText>The diameter of LA was higher in AF(+) patients than in the AF(-) patients (39±6 mm vs. 35±4 mm, p<0.005). In 68.6% of AF(+) patients and in 83.9% of AF(-) patients the anatomical pattern was typical with two right and two left PVs. Additional PVs were detected in 6 patients, only in AF(+) group (p<0.05). Common ostia were more frequently found in AF(+) subjects (37.2% vs. 19.3, p=0,08), mainly left-sided. In AF(+) group mean SI diameters of both-sided superior PVs and left inferior veins were larger. All AP diameters except for right inferior PVs were also larger in AF(+) group than in control cases.</AbstractText>Variations in the PVs anatomy are more common and diameters of ostial portions of the veins are larger in AF patients than in control subjects. These findings suggest that further studies on the role of structural abnormalities of PVs in arrhythmogenesis are needed.</AbstractText>Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
6,437 | Abnormal transmural repolarization process in patients with Brugada syndrome. | Repolarization abnormality, especially during bradycardia, might be critical for initiation of ventricular fibrillation (VF) in patients with Brugada syndrome (BrS), but the contribution of the rate-dependent repolarization dynamics to the occurrence of VF is still unknown.</AbstractText>The aim of our study was to determine the differences in rate-dependent repolarization dynamics between BrS with and without spontaneous VF and between BrS with and without SCN5A mutation.</AbstractText>The subjects were 37 BrS patients with VF (VF(+) group: 10 male subjects) and without VF (VF(-) group: 27 male subjects) and 20 control subjects. Genetic analysis of SCN5A was performed in all 37 BrS patients. The relationships between QT, QTp, Tp-e, and RR intervals were obtained from Holter recordings as first linear regression lines, and the slopes of QT/RR, QTp/RR, and Tp-e/RR linear regression lines as the sensitivity of rate-dependent repolarization dynamics were compared.</AbstractText>QT/RR and Tp-e/RR slopes showed loss of a rate-dependent property in the VF(+) group compared with those in the VF(-) and control groups. There was no significant difference in QTp/RR slope among the VF(+), VF(-) and control groups. The Tp-e interval had a negative correlation with the RR interval in the VF(+) group and a positive correlation with the RR interval in the VF(-) and control groups. There was no significant difference in QT/RR, QTp/RR, and Tp-e/RR slopes between BrS patients with SCN5A mutation and those without SCN5A mutation.</AbstractText>Loss of rate-dependent QT dynamics may be associated with occurrence of VF in BrS.</AbstractText> |
6,438 | Long-term outcomes and clinical predictors for pacing after cardiac transplantation. | Prior studies have yielded inconsistent results on bradyarrhythmias requiring a permanent pacemaker (PPM) after cardiac transplant. This study evaluated the predictors for PPM requirement, long-term outcomes, and influence of implant timing and device programming on prognosis after cardiac transplant.</AbstractText>This study prospectively evaluated 1,307 recipients from 1985 to 2007 at Cleveland Clinic by structured follow-up and compared the outcomes of patients with and without bradyarrhythmias requiring PPM after transplantation. The primary end point was all-cause mortality or retransplant.</AbstractText>Recipients, aged 50 +/- 15 years (donors, 33 +/- 14 years), were monitored 82 +/- 59 months, with PPM indicated in 106 (8.1%), including 61 (57.5%) early and 44 (42.5%) late. Biatrial technique strongly predicted PPM requirement (OR [odds ratio], 2.61; 95% confidence interval [CI], 1.63-4.20; p < 0.001), and survival/retransplant outcomes were comparable between those with early, late, and no PPM requirement: 5-year primary event-free rate was 80.4% (early) vs 72.6% (late; p = 0.480) and 80.4% (early) vs 73.2% (none, p = 0.550) and 72.6% (late) vs 73.2% (none; p = 0.960). Excess atrial fibrillation was noted among PPM recipients (PPM, 12.3% vs no PPM, 6.3%; p = 0.02) with high initial DDD programming in 92.5% (98 of 106). Sinus rhythm with intact atrioventricular conduction at 6 months was present in 69 (85%), yet 67 (67%) remained DDD programmed, with mean 26.0% +/- 38.0% right ventricular pacing.</AbstractText>No excess mortality is associated with a PPM after cardiac transplantation, and biatrial technique strongly predicts PPM requirement. Increased atrial fibrillation among PPM recipients may be related to right ventricular stimulation with dual-chamber pacing.</AbstractText> |
6,439 | Serial evaluation of electrocardiographic left ventricular hypertrophy for prediction of risk in hypertensive patients. | Although the presence and severity of electrocardiographic (ECG) left ventricular hypertrophy (LVH) have been associated with an increased risk of cardiovascular (CV) morbidity and mortality, the relationship of regression of ECG LVH during antihypertensive therapy to CV risk has only recently been examined.</AbstractText>Electrocardiographic LVH was evaluated over time in 9193 hypertensive patients enrolled in the Losartan Intervention for Endpoint Reduction in Hypertension study. Patients were treated with losartan- or atenolol-based regimens and followed with serial ECGs at 6 months and then yearly until death or study end. Electrocardiographic LVH was measured using gender-adjusted Cornell product (RaVL + SV3 [+6 mm in women]) QRS duration) and Sokolow-Lyon voltage (SV1 + RV5/6).</AbstractText>After mean (SD) follow-up of 4.8 (0.9) years, the Losartan Intervention for Endpoint Reduction in Hypertension study composite end point of CV death, nonfatal myocardial infarction, or stroke occurred in 1096 patients. In Cox regression models controlling for treatment type, baseline Framingham risk score, baseline, and in-treatment blood pressure and for severity of baseline ECG LVH by Cornell product and Sokolow-Lyon voltage, lower in-treatment ECG LVH by Cornell product and Sokolow-Lyon voltage were associated with 14% and 17% lower rates, respectively, of the composite CV end point: adjusted hazard ratios (HRs) of 0.86 (95% confidence interval [CI], 0.82-0.90; P < .001) for every 1050 mm . ms (1 SD) decrease in Cornell product and 0.83 (95% CI, 0.78-0.88; P < .001) for every 10.5 mm (1 SD) decrease in Sokolow-Lyon voltage. In parallel analyses, lower Cornell product and Sokolow- Lyon voltage were each independently associated with lower risks of CV mortality (HR, 0.78; 95% CI, 0.73-0.83; P < .001; HR, 0.80; 95% CI, 0.73-0.87; P < .001), of myocardial infarction (HR, 0.90; 95% CI, 0.82-0.98; P = .011; HR, 0.90; 95% CI, 0.81-1.00; P = .043), and of stroke (HR, 0.90; 95% CI, 0.84-0.96; P = .002; HR, 0.81; 95% CI, 0.75-0.89; P < .001). Regression of ECG LVH was also associated with significantly reduced risks of sudden cardiac death, new-onset atrial fibrillation, hospitalization for heart failure, and new-onset diabetes mellitus.</AbstractText>Regression of ECG LVH by Cornell product and/or Sokolow-Lyon voltage criteria during antihypertensive therapy is associated with lower likelihoods of CV morbidity and mortality, all-cause mortality, and new-onset diabetes, independent of blood pressure lowering and treatment modality in essential hypertension. These findings suggest that antihypertensive therapy targeted at regression or prevention of ECG LVH may improve prognosis.</AbstractText> |
6,440 | Percutaneous left ventricular assist device can prevent acute cerebral ischaemia during ventricular fibrillation. | A percutaneous left ventricular assist device has been shown to be able to perfuse cardiac and cerebral tissues during cardiac arrest and may be a useful supplement to current methods in resuscitation. We wished to assess device-assisted circulation during cardiac arrest with microspheres injections and continuous end-tidal CO(2) monitoring, and used cerebral microdialysis to detect ischaemia in the brain.</AbstractText>12 anaesthetised pigs had microdialysis and pressure catheters implanted via craniotomy. The percutaneous assist device was deployed transfemorally. Ventricular fibrillation was induced by angioplasty-balloon occlusion of the left coronary artery. Cerebral microdialysis samples representing 0-20 and 20-40 min of cardiac arrest with assisted circulation were analysed for markers of cerebral injury (glucose, pyruvate, lactate, and glycerol).</AbstractText>Microdialysis showed no ischaemic changes after 20 min of cardiac arrest (P=NS to Baseline for glucose, glycerol, lactate, pyruvate and lactate/pyruvate ratio) in subjects with maintained end-tidal CO(2) values above 1.3 kPa (10 mmHg). After 40 min only lactate showed a significant change compared to Baseline (P<0.05). Microspheres flow to the brain was 57% and myocardial flow was 72% compared to Baseline after 15 min (P<0.05). After 45 min flow declined to 22% and 40% of Baseline, respectively (P=NS vs. 15 min).</AbstractText>A percutaneous left ventricular assist device may prevent ischaemic cerebral injury during cardiac arrest for a limited time. Cerebral injury and tissue perfusion were indicated by end-tidal CO(2).</AbstractText> |
6,441 | Changes in the frequency spectrum, the P-P interval, and the bispectral index during ventricular fibrillation are physiologic indicators of ventricular fibrillation duration. | The 3-phase time-sensitive model by Weisfeldt and Becker in 2002 has resulted in a redirection of efforts toward developing treatment algorithms specific to each phase of cardiac arrest. In this study, a number of physiologic indicators of ventricular fibrillation (VF) duration were investigated. The bispectral index was recorded at 15-second intervals over 12 minutes and recordings of the atrial electrocardiogram and lead II electrocardiogram were acquired simultaneously using Notocord data acquisition software during sinus rhythm, ventricular tachycardia, and VF, and analyzed using a total of 30 porcine models. A number of frequency markers (fast Fourier transform and density and amplitude of peaks [DA]) were derived. There was a direct relationship between VF duration and bispectral index with a Pearson correlation coefficient (mean) of r = -0.91. The P-P interval recorded in the atria during VF, demonstrated similar findings (r = 0.97) when measured against VF duration. It was interesting to note that P waves were still apparent during VF despite the on-going chaotic activity in the ventricles. The DA was calculated for each episode of prolonged VF and an exponential relationship with VF duration was observed. The dominant frequency during VF, DA, the P-P interval, and the BIS index are all potential physiologic indicators of VF duration. |
6,442 | Cardiac magnetic resonance imaging assessment of regional and global left atrial function before and after catheter ablation for atrial fibrillation. | Ablation of the left atrium and pulmonary veins antrum (PVAI) can be an effective treatment of atrial fibrillation (AF). However, there is discrepancy in the literature regarding the effect extensive ablation has on left atrial (LA) function. We sought to evaluate the effect that AF ablation procedures has on global and regional wall motion as assessed by cardiovascular magnetic resonance imaging (MRI).</AbstractText>Consecutive patients undergoing PVAI had cardiac MRI performed preablation and 3 months post ablation. Patients included paroxysmal (n = 16) and persistent/permanent (n = 13). In addition, 12 volunteers underwent cardiac MRI to provide a control population. LA transport function was assessed by obtaining cyclical change indices, total percent emptying, LA stroke volume indices, and LA active percent emptying. Using chordal segment analysis and radial motion of the left atrium, regional motion was assessed throughout the LA emptying cycle.</AbstractText>All four PVs were isolated for all patients. Imaging revealed a significant reduction in LA volumes in AF patients post-PVAI. In the subset of patients with persistent AF, post-PVAI improvements were seen in global (p < 0.01) and regional LA functions (p = 0.01). In the paroxysmal AF patients, post-PVAI measurements revealed decreases in LA transport function (p = 0.02) as well as diminished regional function in the LA lateral wall (p = 0.02). The paroxysmal AF patients had global and regional LA functions comparable to the normal volunteers prior to ablation; however, these were significantly diminished post ablation.</AbstractText>Extensive ablation during PVAI causes mild deterioration in LA function. However, in patients with a high burden of AF, it appears that the positive remodeling that occurs with rhythm restoration outweighs any negative effects of ablation.</AbstractText> |
6,443 | Fluctuation in ventricular sensing leading to underdetection of ventricular fibrillation in a patient with cardiac sarcoidosis. | In this case report, we describe markedly fluctuating ventricular sensing through an implantable cardioverter defibrillator (ICD) over a period of 29 months in a patient with cardiac sarcoidosis. We conclude that the fluctuations in the measured R wave are the result of waxing and waning inflammation associated with sarcoid activity. The patient had a stable medical course throughout the time period studied, including stable immunosuppression and stable electrolytes. We believe this is an example of an important complication of ICD implants in patients with cardiac sarcoidosis and that frequent sensing evaluations are prudent in these patients. |
6,444 | Validating optimal function of the closed loop stimulation sensor with high right septal ventricular electrode placement in 'ablate and pace' patients. | The study aim was to validate the closed loop stimulation (CLS) vs. accelerometer (ACC) rate-responsive sensors with electrodes placed in the right ventricular high septal (RVHS) or right ventricular apical (RVA) lead positions in patients following 'ablate and pace' therapy for persistent atrial fibrillation.</AbstractText>'Ablate and pace' patients were randomised to either RVHS or RVA electrode placement with a dual sensor device. A double-blind crossover study comparing CLS vs. ACC rate-response pacing modes was undertaken. Subjects undertook cardiopulmonary testing with constant workload light exercise followed by a ramp protocol in addition to activity of daily living assessments.</AbstractText>Twenty subjects (14 male; age, 74 +/- 8 years) were studied. Heart rate increase was greater from lying to sitting with ACC. With mental stress, heart rate increase was greater with CLS. Peak heart rates were similar for stair ascent and descent in ACC mode. With CLS mode, however, the peak heart rate was significantly lower for stair descent. There was no difference between modes in mean response time, oxygen deficit, peak VO(2), VO(2) at anaerobic threshold, peak heart rate, total exercise time and total workload. CLS function was equally optimal at both electrode sites.</AbstractText>CLS rate adaptive pacing is appropriate for 'ablate and pace' patients, and this sensor functions equally well using RVA or RVHS lead positions.</AbstractText> |
6,445 | Comparison of acute electrocardiographic presentation in patients with diastolic vs systolic heart failure. | There are limited data comparing admission electrocardiograms (ECGs) in patients with acute diastolic (DHF) vs systolic heart failure (SHF) and their ability to predict cardiac events (CEs). Admission ECGs were evaluated in 241 acute heart failure patients (88 DHF; 153 SHF). DHF was defined as left ventricular ejection fraction >45%. End points consisted of rehospitalization for CEs or death during a 30-day follow-up. DHF patients had more atrial fibrillation (AF) while SHF patients had faster heart rates and longer QRS and QTc duration. There were 68 CEs: 26 (30%) in DHF and 42 (27%) in SHF patients ( P=.728). Multivariate logistic regression analysis revealed that in DHF patients, CEs were associated with nonischemic heart failure, blood urea nitrogen >28 mg/dL, and AF. In the SHF group, CEs were associated with AF. Admission ECG differs between acute DHF and SHF patients. CE rates are similar in both groups; AF is the only ECG parameter predictive of CEs. |
6,446 | Simvastatin alleviates myocardial contractile dysfunction and lethal ischemic injury in rat heart independent of cholesterol-lowering effects. | Statins, the inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, are most frequently used drugs in the prevention of coronary artery disease due to their cholesterol-lowering activity. However, it is not exactly known whether these effects of statins or those independent of cholesterol decrease account for the protection against myocardial ischemia-reperfusion (I/R) injury. In this study, we investigated the effect of 5-day treatment with simvastatin (10 mg/kg) in Langendorff-perfused hearts of healthy control (C) and diabetic-hypercholesterolemic (D-H; streptozotocin + high fat-cholesterol diet, 5 days) rats subjected to 30-min global ischemia followed by 40-min reperfusion for the examination of postischemic contractile dysfunction and reperfusion-induced ventricular arrhythmias or to 30-min (left anterior descending) coronary artery occlusion and 2-h reperfusion for the infarct size determination (IS; tetrazolium staining). Postischemic recovery of left ventricular developed pressure (LVDP) in animals with D-H was improved by simvastatin therapy (62.7+/-18.2 % of preischemic values vs. 30.3+/-5.7 % in the untreated D-H; P<0.05), similar to the values in the simvastatin-treated C group, which were 2.5-fold higher than those in the untreated C group. No ventricular fibrillation occurred in the simvastatin-treated C and D-H animals during reperfusion. Likewise, simvastatin shortened the duration of ventricular tachycardia (10.2+/-8.1 s and 57.8+/-29.3 s in C and D-H vs. 143.6+/-28.6 s and 159.3+/-44.3 s in untreated C and D-H, respectively, both P<0.05). The decreased arrhythmogenesis in the simvastatin-treated groups correlated with the limitation of IS (in % of risk area) by 66 % and 62 % in C and D-H groups, respectively. However, simvastatin treatment decreased plasma cholesterol levels neither in the D-H animals nor in C. The results indicate that other effects of statins (independent of cholesterol lowering) are involved in the improvement of contractile recovery and attenuation of lethal I/R injury in both, healthy and diseased individuals. |
6,447 | Ablate and pace as bail-out therapy in a patient with Fontan correction and malignant atrial tachycardia. | Atrial tachyarhthmias complicating Fontan correction may have a 'malignant' clinical presentation seriously impairing the patient haemodynamic. Current strategies are surgical total cavopulmonary connection with or without antiarrhythmic surgery or transcatheter ablation. We describe the case of a patient who previously underwent atriocaval Fontan correction and later presented with refractory atrial tachycardia responsible for relapsing syncope. After a failed attempt at surgical conversion, and while waiting for heart transplantation, he was submitted to ablation of the atrioventricular node through an aortic retrograde approach and ventricular pacing through the coronary sinus tree. One year later, the patient is doing well, displaying a stable functional recovery and excellent pacing lead performances. An ablate and pace approach may deserve consideration in selected Fontan patients experiencing life-threatening atrial arrhythmias. |
6,448 | Arrhythmogenic right ventricular cardiomyopathy presenting with intra-operative aborted sudden cardiac death and TakotsuboLike left ventricular functional abnormalities. | A 46-year-old female under treatment with flecainide for atrial fibrillation developed cardiopulmonary arrest secondary to ventricular fibrillation during an elective laparoscopic cholecystectomy. The ECG after cardioversion demonstrated a prolonged QTc interval with elevated cardiac enzymes. A diagnosis of Takotsubo cardiomyopathy was made after angiography demonstrated normal coronary arteries with characteristic ballooning of the left ventricle seen on the left ventriculogram. However, right ventricular biopsy revealed significant fibrofatty infiltration of the myocardium. Treatment with flecainide and early features of arrhythmogenic right ventricular dysplasia may have predisposed the patient to ventricular fibrillation during the transient left ventricular dysfunction of Takotsubo cardiomyopathy. |
6,449 | Nicosia General Hospital cardiac arrest team: first year's practice and outcomes of in-hospital resuscitation. | In 2007, Nicosia General Hospital implemented a resuscitation policy. 378 nurses and 120 doctors were successfully trained in advanced life support (ALS) in order to staff cardiac arrest teams. The aim of this study was to assess the frequency of cardiac arrest and resuscitation outcomes in Nicosia General Hospital and assess any associations between the survival rate and the patient's characteristics. We also aimed to evaluate the effectiveness of in-hospital resuscitation in order to detect ways of improvement.</AbstractText>We prospectively analyzed the data on all cardiac arrest calls in Nicosia General Hospital between January and December 2007. Data were collected using the Utstein style.</AbstractText>The cardiac arrest team (CAT) was called 83 times, of which 10 were false alarms. Cardiac arrest was identified in 69 calls, while 4 calls were respiratory arrests. The patients' mean age was 70.8 years (95% CI: 66.6-75.1). In 86% the initial rhythm was asystole/pulseless electrical activity (PEA) and in 14% ventricular fibrillation/tachycardia (VF/VT). Return of spontaneous circulation was achieved in 52% of the cases. Survival to discharge was achieved in 17.8% of the patients with arrest and in 14.5% of cardiac arrests. Patients with an initial rhythm of asystole/PEA were discharged in 5% and patients with VF/VT in 70% of cases. About 36% of the patients less than 60 years old and 12% of the patients older than 60 were discharged. The CAT arrived within 1.6 minutes, first shock in VF/VT was delivered within 1.5 minutes and the first adrenaline dose in asystole/PEA was given within 2.7 minutes.</AbstractText>It is more likely for our patients to survive to discharge if they are less than 60 years old, they are hospitalized in the cardiology department and the initial rhythm is VF/VT. Our outcomes are similar to survival rates in larger studies. However, points of improvement have been identified and interventions need to be made in order to improve documentation and outcomes of in-hospital arrests.</AbstractText> |
6,450 | Mitral valve replacement with the pulmonary autograft: midterm results. | We performed mitral valve replacement with a pulmonary autograft using the technique described by us earlier and present the results.</AbstractText>Between August 2000 and July 2007, 19 patients (16 male patients; age, 30-58 years) with isolated calcific mitral stenosis (n = 16) or mixed mitral stenosis and regurgitation (n = 3) underwent mitral valve replacement with a pulmonary autograft. Sixteen patients were in New York Heart Association class III and 3 were in New York Heart Association class IV preoperatively. Eight patients were in atrial fibrillation. The autograft implantation was achieved by using a scalloped stent of polytetrafluoroethylene felt for external support of the autograft. No anticoagulants were prescribed.</AbstractText>There were 3 early deaths, one each caused by ventricular dysfunction, ventricular arrhythmias, and autograft dehiscence requiring early reoperation. Follow-up of survivors ranged from 34 to 99 months (mean, 71.9 +/- 18.2 months; median, 75 months). The mean valve area was 2.96 +/- 0.9 cm(2) (range, 2.2-4.3 cm(2)). Fourteen survivors are in New York Heart Association class I, and 2 are in NYHA class II; 4 continue to be in atrial fibrillation. Follow-up echocardiograms (n = 16), magnetic resonance imaging (n = 6), and cardiac catheterization (n = 4) have demonstrated no significant autograft and pulmonary homograft dysfunction. There were no late deaths or reoperations or thromboembolic complications.</AbstractText>Mitral valve replacement with a pulmonary autograft, a complex operation, can be performed in selected patients with acceptable results. The use of our technique of autograft implantation offers several advantages and avoids exposure of the scaffold to the bloodstream.</AbstractText> |
6,451 | Use of preoperative natriuretic peptides and echocardiographic parameters in predicting new-onset atrial fibrillation after coronary artery bypass grafting: a prospective comparative study. | Atrial fibrillation (AF) is a common complication after coronary artery bypass grafting (CABG). We prospectively compared the ability of echocardiographic parameters and the cardiac neurohormones, brain natriuretic peptide (BNP), and N-terminal pro-brain natriuretic peptide (NT-proBNP) to predict AF in this setting.</AbstractText>We recruited 275 patients undergoing nonemergency CABG. Patients undergoing valve surgery or with prior atrial dysrhythmia (based on clinical history and review of medical records) were excluded. Echocardiography was performed, and natriuretic peptide levels were measured, 24 hours before surgery. The primary end point was postoperative AF lasting >30 seconds.</AbstractText>The only significant echocardiographic predictors of postoperative AF (n = 107, 39%) were the transmitral E to A-wave ratio and the early mitral annulus velocity. Levels of BNP and NT-proBNP were higher in patients who developed AF. Both natriuretic peptides, but none of the echocardiographic parameters, remained independently predictive in multivariable analysis. The optimum cut points for predicting AF were 31 pg/mL for BNP (odds ratio [OR] 2.74, P = .001) and 74 pg/mL for NT-proBNP (OR 2.74, P = .003).</AbstractText>Levels of BNP and NT-proBNP are independent, though modestly effective, predictors of AF after isolated CABG. In contrast, none of the echocardiographic parameters assessed, including measures of LV systolic function and filling pressure, were independently predictive.</AbstractText> |
6,452 | The association between early ventricular arrhythmias, renin-angiotensin-aldosterone system antagonism, and mortality in patients with ST-segment-elevation myocardial infarction: Insights from Global Use of Strategies to Open coronary arteries (GUSTO) V. | The long-term prognostic significance of early (<48 hours) ventricular fibrillation (VF) or sustained ventricular tachycardia (VT) in patients with an acute myocardial infarction remains controversial. Emerging data suggest that some of the benefit of renin-angiotensin-aldosterone system (RAAS) antagonism may be derived from a reduction in the incidence of these arrhythmias in the setting of acute myocardial infarction.</AbstractText>We assessed the relationship between early VF/VT (defined as within 48 hours after admission) and mortality in 16,588 patients from global use of strategies to open coronary arteries (GUSTO) V trial. Furthermore, we examined the relationship between baseline use of angiotensin-converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB), early VF/VT, and mortality.</AbstractText>Early VF or VT occurred in 732 (4.4%) patients. Compared to patients without VF/VT, those experiencing early VF or VT had a significant increase in 30-day mortality (22% vs 5%, P < .001). Baseline use of an ACEI/ARB was associated with a decreased incidence of early VF/VT (odds ratio 0.65, 0.47-0.89, P = .008). A lower 30-day mortality was seen in patients with early VF/VT on baseline ACEI/ARB compared with patients with early VF/VT not receiving an ACEI/ARB at baseline (17.7% vs 24.2%, respectively, P = .04). The association between baseline RAAS antagonism and mortality persisted after adjustment for multiple confounders.</AbstractText>In patients presenting with acute myocardial infarction, early VF/VT identifies those at increased risk for 30-day mortality. Baseline use of RAAS antagonists is associated with a reduced incidence of malignant arrhythmias. Identifying how this association impacts short-term mortality in this patient population requires further prospective evaluation.</AbstractText> |
6,453 | Rates and predictors of appropriate implantable cardioverter-defibrillator therapy delivery: results from the EVADEF cohort study. | The implantable cardioverter defibrillator (ICD) is the therapy of choice in patients at risk for sudden cardiac death in both primary and secondary prevention indication. There are no recent data concerning the delivery rate and etiology of appropriate ICD therapies in routine medical care.</AbstractText>The EVADEF study was a French multicenter, prospective, observational cohort study of ICD patients with a 2-year follow-up. Every 6 months we recorded patients' survival status and evaluated appropriate ICD therapies-antitachycardia pacing or shocks. Causes of ICD activation were also recorded from among ventricular tachycardia (VT), fast VT and ventricular fibrillation (VF).</AbstractText>From 2001 to 2003, 2296 unselected patients were implanted and followed until 2005. During a mean follow-up of 20.5 months, 274 deaths occurred. In 2009 patients with cardiopathy, 22 patients per 100 person-years had at least one appropriate therapy. Twenty-four and 11 patients per 100 person-years had at least one therapy in secondary and primary prevention, respectively. Age >65 years, left ventricular ejection fraction <30% and secondary prevention were independently associated with appropriate therapy. Besides, 5 patients per 100 person-years had at least 1 episode of life-threatening arrhythmia (fast VT or VF). Left ventricular ejection fraction <30% and secondary prevention were independently associated with life-threatening arrhythmia. In 287 patients without cardiopathy, the rate of appropriate therapy was twice as less, whereas the rate of life-threatening arrhythmia was similar.</AbstractText>Over a 24-month follow-up, the rate of appropriate therapy was substantial while few patients had life-threatening arrhythmia. Appropriate therapies and life-threatening arrhythmia were more frequent in patients with secondary prevention indication.</AbstractText> |
6,454 | Statins reduce appropriate cardioverter-defibrillator shocks and mortality in patients with heart failure and combined cardiac resynchronization and implantable cardioverter-defibrillator therapy. | Of 209 patients with heart failure treated with combined cardiac resynchronization therapy and implantable cardioverter-defibrillator therapy, appropriate cardioverter-defibrillator shocks occurred at 34-month follow-up in 22 of 121 patients (18%) on statins and in 30 of 88 patients (34%) not on statins (P = .009). Deaths occurred in 3 of 121 patients (2%) on statins and in 9 of 88 patients (10%) not on statins (P = .017). Stepwise Cox regression analysis showed that significant independent prognostic factors for appropriate shocks were use of statins (risk ratio = 0.46), smoking (risk ratio = 3.5), and diabetes (risk ratio = 0.34). Significant independent prognostic factors for the time to mortality were use of statins (risk ratio = 0.05), use of digoxin (risk ratio = 4.2), systemic hypertension (risk ratio = 14.2), diabetes (risk ratio = 4.3), and left ventricular ejection fraction (risk ratio = 1.1). |
6,455 | Atrial fibrillation in primary aldosteronism. | Primary aldosteronism (PA) is caused by autonomous hypersecretion of aldosterone from the adrenal cortex, classically from an adenoma, resulting in sodium and water retention, hypokalaemia and raised blood pressure. The sodium and water retention causes suppression of renin release. The possible cardiac sequelae of aldosterone excess are encountered primarily in patients with secondary hyperaldosteronism due to heart failure, where plasma renin, angiotensin and aldosterone levels are all raised. However, there is also evidence that primary aldosterone excess, in the presence of low renin levels, may also be cardiotoxic.</AbstractText>In this report, we describe five patients with PA, who developed atrial fibrillation (AF) in the absence of structural cardiac lesions and in one case despite good control of blood pressure and electrolytes.</AbstractText>In patients with hypertension and AF, who have no evidence of coronary disease or any other underlying cause of AF with preserved systolic function, a diagnosis of PA should be considered.</AbstractText> |
6,456 | Angiotensin II does not influence expression of sarcoplasmic reticulum Ca2 + ATPase in atrial myocytes. | The sarcoplasmic reticulum Ca(2+) ATPase (SERCA) is essential for the regulation of the intracellular calcium level in cardiomyocytes. Previous studies have found that angiotensin II (Ang II) decreased SERCA2 gene expression in ventricular myocytes. Alteration of SERCA activity is important in the mechanism of atrial fibrillation. The present study was undertaken to examine Ang II effects on atrial myocytes.</AbstractText>An approximately 1.75-kb promoter region of SERCA2 gene was cloned with the pGL3 luciferase vector. The direct effects of Ang II on SERCA2 gene expression in HL-1 atrial myocytes were examined by promoter activity assay, followed by Western blot analysis for protein levels and quantitative real-time reverse transcription polymerase chain reaction for mRNA amounts.</AbstractText>Ang II did not increase the promoter activity of the 1,754-bp promoter-receptor construct of the SERCA2 gene. The levels of SERCA2 protein and mRNA were also unchanged at different time points after Ang II treatment.</AbstractText>Although Ang II had prominent effects on SERCA2 in ventricular myocytes, it did not alter SERCA2 gene expression and protein levels in atrial myocytes. We provide a model for further investigation of the regulation of SERCA2 gene expression in atrial myocytes.</AbstractText> |
6,457 | Redox modification of ryanodine receptors underlies calcium alternans in a canine model of sudden cardiac death. | Although cardiac alternans is a known predictor of lethal arrhythmias, its underlying causes remain largely undefined in disease settings. The potential role of, and mechanisms responsible for, beat-to-beat alternations in the amplitude of systolic Ca(2+) transients (Ca(2+) alternans) was investigated in a canine post-myocardial infarction (MI) model of sudden cardiac death (SCD).</AbstractText>Post-MI dogs had preserved left ventricular (LV) function and susceptibility to ventricular fibrillation (VF) during exercise. LV wedge preparations from VF dogs were more susceptible to action potential (AP) alternans and the frequency-dependence of Ca(2+) alternans was shifted towards slower rates in myocytes isolated from VF dogs relative to controls. In both groups of cells, cytosolic Ca(2+) transients ([Ca(2+)](c)) alternated in phase with changes in diastolic Ca(2+) in sarcoplasmic reticulum ([Ca(2+)](SR)), but the dependence of [Ca(2+)](c) amplitude on [Ca(2+)](SR) was steeper in VF cells. Abnormal ryanodine receptor (RyR) function in VF cells was indicated by increased fractional Ca(2+) release for a given amplitude of Ca(2+) current and elevated diastolic RyR-mediated SR Ca(2+) leak. SR Ca(2+) uptake activity did not differ between VF and control cells. VF myocytes had an increased rate of reactive oxygen species production and increased RyR oxidation. Treatment of VF myocytes with reducing agents normalized parameters of Ca(2+) handling and shifted the threshold of Ca(2+) alternans to higher frequencies.</AbstractText>Redox modulation of RyRs promotes generation of Ca(2+) alternans by enhancing the steepness of the Ca(2+) release-load relationship and thereby providing a substrate for post-MI arrhythmias.</AbstractText> |
6,458 | Discovery of a class of potent gap-junction modifiers as novel antiarrhythmic agents. | In an effort to discover potent, orally bioavailable compounds for the treatment of atrial fibrillation (AF) and ventricular tachycardia (VT), we developed a class of gap-junction modifiers typified by GAP-134 (1, R(1)=OH, R(2)=NH(2)), a compound currently under clinical evaluation. Selected compounds with the desired in-vitro profile demonstrated positive in vivo results in the mouse CaCl(2) arrhythmia model upon oral administration. |
6,459 | New pharmacological strategies for the treatment of atrial fibrillation. | Atrial fibrillation (AF) is a growing clinical problem, increasing in prevalence as the population of the United States and countries around the world ages. Intensive research aimed at improving prevention, diagnosis, and treatment of AF is ongoing. Although the use and efficacy of catheter ablation-based approaches in AF treatment have increased significantly in the last decade, pharmacological agents remain the first-line therapy for rhythm management of AF. Currently available anti-AF agents are generally only moderately effective and associated with extracardiac toxicity and/or a risk for development of life-threatening ventricular arrhythmias. Included among current investigational strategies for improving the effectiveness and safety of anti-AF drugs is the development of (1) Agents that produce atrial-specific or predominant inhibition of I(Kur), I(K-ACh), or I(Na); (2) "Upstream therapies" that effect nonion channel targets that reduce atrial structural remodeling, hypertrophy, dilatation, inflammation, oxidative injury, etc; (3) Derivatives of "old" anti-AF drugs with an improved safety pharmacological profile; and (4) Gap junction therapy aimed at improving conduction without affecting sodium channels. This review focuses on new pharmacological approaches under investigation for the treatment of AF. |
6,460 | Surface ECG characteristics of ventricular tachyarrhythmias before degeneration into ventricular fibrillation in patients with Brugada-type ECG. | This study was designed to evaluate whether the right ventricular outflow tract (RVOT) is the arrhythmogenic focus in Brugada syndrome. We enrolled 45 patients with Brugada-type ECG who underwent programmed ventricular stimulation and inducible ventricular fibrillation (VF). In 25 of these 32 patients, repetitive VT was observed before degeneration into VF. The QRS morphology of surface ECG and intracardiac electrograms were evaluated to determine the origin of the ventricular tachycardia (VT) that degenerated into VF. The VT morphology was a left bundle branch block pattern with an inferior axis in 22 of 28 VTs and the intracardiac conduction sequence during VT revealed activation from the RVOT to the RV apex in these 22 VTs. The majority of the patients with Brugada syndrome showed repetitive VT originating from the RVOT that degenerated into VF. The RVOT may be an arrhythmogenic focus in patients with Brugada syndrome. |
6,461 | Blood pressure control and the reduction of left atrial overload is essential for controlling atrial fibrillation. | The purpose of this study was to investigate whether the ideal control of atrial fibrillation (AF) associated with hypertensive patients depends on the usage of renin-angiotensin system (RAS) inhibitors or whether it occurs regardless of the kind of antihypertensive agents used. The control of AF was compared in 112 outpatients between 1) those with or without the administration of RAS inhibitors, and 2) those with an ideal or poor control of the blood pressure (BP) regardless of the kind of antihypertensive therapy used. The therapies with or without RAS inhibitors did not yield any significant difference in the AF control states, even though RAS inhibitors had been administered to the patient group with a high proportion of organic heart disease. The ideal BP control group exhibited a significantly better AF control in comparison to the poor BP control group. The former group had a significantly smaller left atrial diameter determined by ultrasonic echocardiography. BP control itself may essentially be important for preventing AF in the general patient population. Poor BP control seemed to have an affect on worsening AF possibly via left ventricular diastolic dysfunction, followed by left atrial overload. |
6,462 | Opposing effects of bepridil on ventricular repolarization in humans. Inhomogeneous prolongation of the action potential duration vs flattening of its restitution kinetics. | Bepridil is highly effective in the treatment of atrial fibrillation, but its clinical usefulness is limited by a potential risk for the drug-induced Torsades de pointes (TdP) in association with its Class III action.</AbstractText>Monophasic action potentials (MAPs) were recorded from the right ventricular outflow tract (RVOT) and apex (RVA) in 9 patients treated with bepridil (172 +/-26 mg/day) and 10 control patients. Bepridil significantly increased the steady-state MAP durations at 90% repolarization (MAPD(90S) in a rate-independent manner at pacing cycle lengths ranging from 330 to 750 ms. The bepridil-induced prolongation of the MAPD(90) was greater in RVOT (approximately 13%) than RVA (approximately 8%). Bepridil flattened the MAPD(90) restitution slope estimated by an S1-S2 protocol in both the RVOT (0.65 +/-0.22 vs 0.95 +/-0.38) and RVA (0.65 +/-0.14 vs 0.94 +/-0.29). The T(peak-end) interval in the ECG was increased by bepridil for S1 but not S2 at the shortest diastolic interval to produce a ventricular response.</AbstractText>Bepridil produces an inhomogeneous prolongation of the MAPDs, but flattens their restitution kinetics in the human ventricle. The former effect would favor the functional reentry predisposing to TdP, whereas the latter one would counteract that by reducing the dynamic instability of the repolarization.</AbstractText> |
6,463 | Massive systemic air embolism during percutaneous radiofrequency ablation of a primary lung tumor. | We report the case of a systemic air embolism occurring during pulmonary radiofrequency ablation. At the end of the procedure, the patient experienced a sudden myocardial infarction, complicated by ventricular fibrillation, cardiac arrest, and cerebral infarction. Thoracic computed tomography showed an air-blood level inside the left atrium and ventricle, the aortic arch, and the coronary arteries. Cerebral computed tomography showed an infarct in the frontoparietal area. Myocardial infarction and stroke responded to resuscitation measures, including hyperbaric oxygenation. The occurrence of this life-threatening event confirms the need to train experienced anesthesiologists in these new invasive approaches to cancer treatment. |
6,464 | Concealed antegrade penetration of the atrio-ventricular node. | We present a patient with paroxysmal, non-sustained atrial tachycardia (AT) on routine surveillance 24-hour Holter post pulmonary vein isolation (PVI). Several asymptomatic ventricular pauses are noted to follow each burst of AT. We postulate that these pauses are due to the resultant concealed penetration of the atrio-ventricular node (AVN) in combination with sino-atrial node overdrive suppression. Recognition of this physiological phenomenon may help avoid unnecessary intervention arising from Holter recording misinterpretation. |
6,465 | Role of proinflammatory markers and NT-proBNP in patients with an implantable cardioverter-defibrillator and an electrical storm. | Several studies have attempted to identify risk factors for the development of an electrical storm (ES), which is defined as 3 separate ventricular tachyarrhythmic (VT/VF) events, but in the majority of studies no triggers have been found. However, little is known about the role of inflammation and NT-proBNP in patients with ES. The aim of this study was therefore to assess the relationship of Interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP) and NT-proBNP serum concentrations in ICD-patients with or without single spontaneous ventricular tachyarrhythmic events (VT/VF) and in ES.</AbstractText>Markers were determined in 51 patients without ICD-intervention, in 15 ICD-patients with single VT/VF-episodes during 9-months follow-up and in 20 ICD-patients with ES (blood sampling performed within 60min after fulfilling ES criteria). VT/VF-episodes were analysed by stored ICD-electrograms.</AbstractText>All patients had idiopathic dilated cardiomyopathy (n=23) or coronary artery disease (n=63). Patients with ES revealed significantly higher mean serum concentrations of all markers (IL-6 15.19+/-10.34 pg/mL, hs-CRP 20.12+/-14.4 mg/L, NT-proBNP 4799+/-4596 pg/mL) compared to baseline values of patients with single VT/VF-events during follow-up (IL-6 8.37+/-5.8 pg/mL (p=0.03), hs-CRP 4.7+/-5.3 mg/dL (p<0.001), NT-proBNP 1913+/-2665pg/mL (p=0.04)) and compared to baseline values of ICD-patients without device intervention (IL-6 4.62+/-3.66 pg/mL (p<0.001), hs-CRP 4.1+/-3.4 mg/L (p<0.001), NT-proBNP 1461+/-2281pg/mL (p<0.001)). In 9/20 patients presenting with ES (45%) baseline values were available. All markers were significantly higher during ES compared to event-free determination (IL-6 14.54+/-10.43 vs. 7.03+/-2.83 pg/mL (p=0.04), hs-CRP 19.07+/-16.07 vs. 6.5+/-3.9 mg/L (p=0.02), NT-proBNP 4218+/-2561 vs. 2099+/-1279 pg/mL (p=0.03)).</AbstractText>Electrical storm is associated with significantly elevated IL-6, hs-CRP and NT-proBNP serum concentrations in ICD-patients with structural heart disease. Thus, ES may be triggered by proinflammatory activity. Combined intraindividual elevation of determined markers might help to identify patients at risk of impending electrical storm.</AbstractText> |
6,466 | Comparison of efficacy of pulsed biphasic waveform and rectilinear biphasic waveform in a short ventricular fibrillation pig model. | The waveform designs and their relative defibrillation efficacy of external biphasic waveforms may differ remarkably among manufacturers. In this study, we compared pulsed biphasic waveform (PBW) with rectilinear biphasic waveform (RBW) and their effects on terminating ventricular fibrillation (VF).</AbstractText>VF was electrically induced and untreated for 10s in 6 domestic pigs weighing between 56 and 70 kg. The animals were then randomized to attempt defibrillation with either a PBW or RBW shock at energy levels of 50-200 J. If the delivered shock failed to terminate VF, a 150 J rescue shock was delivered with the same waveform. After a recovery interval of 4 min, the sequences were repeated for a total of 60 test shocks. The 50% and 80% defibrillation thresholds (DFT) were then calculated for the compared waveforms.</AbstractText>No differences were observed in energy DFT50 and DFT80. Although the peak current and average current of the PBW were higher than RBW, there was no change observed in ST segment following shocks with both waveforms.</AbstractText>In the setting of this experiment, there was no difference in terms of defibrillation efficacy and myocardial injury related to the electrical shocks of the two waveforms.</AbstractText> |
6,467 | Basic life support with four different compression/ventilation ratios in a pig model: the need for ventilation. | During cardiac arrest the paramount goal of basic life support (BLS) is the oxygenation of vital organs. Current recommendations are to combine chest compressions with ventilation in a fixed ratio of 30:2; however the optimum compression/ventilation ratio is still debatable. In our study we compared four different compression/ventilation ratios and documented their effects on the return of spontaneous circulation (ROSC), gas exchange, cerebral tissue oxygenation and haemodynamics in a pig model.</AbstractText>Study was performed on 32 pigs under general anaesthesia with endotracheal intubation. Arterial and central venous lines were inserted. For continuous cerebral tissue oxygenation a Licox PtiO(2) probe was implanted. After 3 min of cardiac arrest (ventricular fibrillation) animals were randomized to a compression/ventilation-ratio 30:2, 100:5, 100:2 or compressions-only. Subsequently 10 min BLS, Advanced Life Support (ALS) was performed (100%O(2), 3 defibrillations, 1mg adrenaline i.v.). Data were analyzed with 2-factorial ANOVA.</AbstractText>ROSC was achieved in 4/8 (30:2), 5/8 (100:5), 2/8 (100:2) and 0/8 (compr-only) pigs. During BLS, PaCO(2) increased to 55 mm Hg (30:2), 68 mm Hg (100:5; p=0.0001), 66 mm Hg (100:2; p=0.002) and 72 mm Hg (compr-only; p<0.0001). PaO(2) decreased to 58 mmg (30:2), 40 mm Hg (100:5; p=0.15), 43 mm Hg (100:2; p=0.04) and 26 mm Hg (compr-only; p<0.0001). PtiO(2) baseline values were 12.7, 12.0, 11.1 and 10.0 mm Hg and decreased to 8.1 mm Hg (30:2), 4.1 mm Hg (100:5; p=0.08), 4.3 mm Hg (100:2; p=0.04), and 4.5 mm Hg (compr-only; p=0.69).</AbstractText>During BLS, a compression/ventilation-ratio of 100:5 seems to be equivalent to 30:2, while ratios of 100:2 or compressions-only detoriate peripheral arterial oxygenation and reduce the chance for ROSC.</AbstractText> |
6,468 | [Iatrogenic risk of permanent pacemaker and defibrillator implantation]. | The considerable evolution in technique and hardware, occurred over the past three decades, has greatly simplified the implantation procedure of pacemakers and cardioverter-defibrillators. Indeed, the introduction of relatively simple and safe methods of central venous access, and the miniaturization of the generator with subcutaneous placement have facilitated the implantation. However, inherent with cardiac pacing and defibrillating therapy is the potential for the occurrence of an early or delayed untoward event. Although skill, experience, and technique are all mitigating factors, every cardiologist should know potential complications and should be able to stratify overall risk related to a device implantation. Thus, both the implanting physician or the clinical cardiologist must be concerned not only with measures to avoid complications, but also with their early recognition and treatment. |
6,469 | Protective effect of grape seed proanthocyanidins extracts on reperfusion arrhythmia in rabbits. | Reperfusion arrhythmia (RA) is one of the main complications which are also an important cause of sudden cardiac death. The aim of this study was to clarify whether grape seed proanthocyanidins extracts (GSPE) were therapeutic agents against RA. The models of cardiac ischemic reperfusion injury were established in rabbits. GSPE (100 mg/kg, and 250 mg/kg body weight/d, respectively) were administered for 3 wk. The incidence rates of arrhythmias before and after reperfusion of each group were recorded, cardiac infarction area and microstructures of cardiac cells of each rabbit were observed, and the expression of connexin 43 (Cx43) was detected by immunohistochemistry. Data were analyzed using the Leica Qwin V3 image analysis system. Reperfusion induced arrhythmia. Ventricular fibrillation (VF) occurred during the early phase of reperfusion after ischemia. Our results showed that GSPE treatment significantly reduced the incidence of VF and the infarction size compared with the model control group. Moreover, the intercalated disks in the model control group showed collapse, displacement and even the formation of cisterns. After being treated by GSPE, the intercalated disks were improved and there were less collapse and displacement. The expression of Cx43 was improved by GSPE treatment, and high dose of GSPE resulted in significant improvement. The study suggests that GSPE has a protective effect on myocardial ischemic reperfusion arrhythmias, which may be mediated by inhibiting the degradation of Cx43 and enhancing gap junctional conductance. |
6,470 | Treating myocardial stunning randomly, with either propofol or isoflurane following transient coronary occlusion and reperfusion in pigs. | Propofol and isoflurane may be used during fast track anesthesia for off-pump bypass, where transient ischemia is common. The purpose of this study was to compare the effects of propofol vs isoflurane in a porcine model of acute coronary occlusion. Twenty five pigs were randomized to receive general anesthesia with either isoflurane, 1 MAC (n = 13), or propofol, 3 mg/kg bolus followed by 200 microg/ kg/min infusion (n = 12). Pressure-tipped catheters were placed in the left ventricle (LV) and carotid artery; cardiac output was measured by ultrasound; two pairs of ultrasonic dimension catheters were placed in the subendocardium of LV. The slope of LV end-systolic pressure-volume relationship (Emax) was calculated. Reversible ischemia for 15 mins was accomplished with an occluder around the left anterior descending artery followed by reperfusion period. Measurements were done at baseline, end ischemia, early (5 min) and late (30 min) reperfusion. The data collected included systemic hemodynamics, LV end-diastolic pressure (LVEDP), dP/dt, Emax, and the presence of ventricular arrhythmias. The number of animals studied to completion was 19 (n = 11 in the isoflurane group; n = 8 in propofol group). There was a significant difference in Emax between isoflurane and propofol during early and late reperfusion [3.4 (0.5) and 4.0 (0.3) vs 2.6 (0.4) and 3.2 (0.5) mmHg/sec, respectively; P < 0.05]. Postreperfusion ventricular fibrillation occurred in 54% animals in the propofol group vs none in the isoflurane group ( P 0.05). Isoflurane administration was found to be cardioprotective against ventricular depression and arrhythmias compared to propofol. |
6,471 | Interatrial mechanical dyssynchrony worsened atrial mechanical function in sinus node disease with or without paroxysmal atrial fibrillation. | Atrial electromechanical dysfunction might contribute to the development of atrial fibrillation (AF) in patients with sinus node disease (SND). The aim of this study was to investigate the prevalence and impact of atrial mechanical dyssynchrony on atrial function in SND patients with or without paroxysmal AF.</AbstractText>We performed echocardiographic examination with tissue Doppler imaging in 30 SND patients with (n = 11) or without (n = 19) paroxysmal AF who received dual-chamber pacemakers. Tissue Doppler indexes included atrial contraction velocities (Va) and timing events (Ta) were measured at midleft atrial (LA) and right atrial (RA) wall. Intraatrial synchronicity was defined by the standard deviation and maximum time delay of Ta among 6 segments of LA (septal/lateral/inferior/anterior/posterior/anterospetal). Interatrial synchronicity was defined by time delay between Ta from RA and LA free wall.</AbstractText>There were no differences in age, P-wave duration, left ventricular ejection fraction, LA volume, and ejection fraction between with or without AF. Patients with paroxysmal AF had lower mitral inflow A velocity (70 +/- 19 vs 91 +/- 17 cm/s, P = 0.005), LA active empting fraction (24 +/- 14 vs 36 +/- 13%, P = 0.027), mean Va of LA (2.6 +/- 0.9 vs 3.4 +/- 0.9 cm/s, P = 0.028), and greater interatrial synchronicity (33 +/- 25 vs 12 +/- 19 ms, P = 0.022) than those without AF. Furthermore, a lower mitral inflow A velocity (Odd ratio [OR]= 1.12, 95% Confidence interval [CI] 1.01-1.24, P = 0.025) and prolonged interatrial dyssynchrony (OR = 1.08, 95% CI 1.01-1.16, P = 0.020) were independent predictors for the presence of AF in SND patients.</AbstractText>SND patients with paroxysmal AF had reduced regional and global active LA mechanical contraction and increased interatrial dyssychrony as compared with those without AF. These findings suggest that abnormal atrial electromechanical properties are associated with AF in SND patients.</AbstractText> |
6,472 | The value of irbesartan in the management of hypertension. | Elevated blood pressure levels are highly prevalent and are a major reason for cardiovascular events and thus place a significant financial burden on healthcare systems worldwide. Guidelines recommend five first-line anti-hypertensive drug classes, but compelling indications may indicate favoring one drug class over another. Angiotensin receptor blockers (ARBs) have demonstrated a blood pressure lowering efficacy which is at least comparable with other drug classes, including ACE inhibitors (ACE-I), beta-blockers, calcium channel blockers and diuretics. They have, in addition, a lower side effect profile than other drug classes and patients on ARBs are more persistent with therapy. Compelling indications for the use of ARBs are heart failure, post-myocardial infarction, diabetic nephropathy, proteinuria/microalbuminuria, left ventricular hypertrophy, atrial fibrillation, metabolic syndrome and ACE-I induced cough. The ARB irbesartan has demonstrated a high efficacy in lowering blood pressure, which has been shown to be at least comparable with ACE-Is and superior to other ARBs such as losartan and valsartan. This translated into a better cost-effectiveness for irbesartan than for valsartan and losartan in the treatment of hypertension. In addition, irbesartan has been shown to be effective in both early and late stage diabetic nephropathy. It has further demonstrated considerable cost savings over standard therapy including beta-blockers, diuretics and non-dihydropyridine calcium channel blockers at all stages of kidney disease. Based on efficacy data from the Irbesartan Diabetic Nephropathy Trial and Reduction of Endpoints in NIDDM (non insulin dependant diabetes melitis) with the Angiotensin II Antagonist Losartan Study, it has also demonstrated cost savings over losartan in late stage renal disease. While both losartan and irbesartan are registered for the treatment of late stage diabetic nephropathy, irbesartan is also registered for early stage diabetic nephropathy in the EU. In summary, the data from randomized clinical trials on the efficacy of antihypertensive drugs provides an indication of their real value to patients. In addition observational data from clinical practice and proven end-organ protection in diabetic nephropathy provides further evidence of the true value of irbesartan compared to other ARBs in the treatment of hypertension. |
6,473 | Analysis of surface atrial signals: time series with missing data? | Uncovering of the atrial signal for patients undergoing episodes of atrial fibrillation is usually obtained from surface ECG by removing waves induced by ventricular activities. Once earned the atrial signal, the detection of the dominant fibrillation frequency is often the main (and only) goal. In this work we verified if subtraction of the ventricular activity might be avoided by performing spectral analysis on those ECG segments where ventricular activity is absent, (i.e. the T-Q intervals). While the approach might seem crude, in here the question was recast into a problem of missing data in a long time series and proper methods were applied: the Lomb periodogram and the iterative Singular Spectrum Analysis. The two methods were tested on both simulated signals and "realistic" atrial signals constructed using the ECG recordings provided by the 2004 Computers in Cardiology competition. The results obtained showed that both techniques were able to provide a reliable quantification of the dominant oscillation, with a slightly superior performance of the iterative Singular Spectrum Analysis. Absolute errors larger than 1.0 Hz were unlikely (p < 0.05) up to 130-140 bpm. Such level of agreement is consistent with similar comparative works where techniques for separating the atrial signal from ventricular waves were considered. |
6,474 | Systematic assessment of patients with unexplained cardiac arrest: Cardiac Arrest Survivors With Preserved Ejection Fraction Registry (CASPER). | Cardiac arrest without evident cardiac disease may be caused by subclinical genetic conditions. Provocative testing to unmask a phenotype is often necessary to detect primary electrical disease, direct genetic testing, and perform family screening.</AbstractText>Patients with apparently unexplained cardiac arrest and no evident cardiac disease (normal cardiac function on echocardiogram, no evidence of coronary artery disease, and a normal ECG) underwent systematic evaluation that included cardiac magnetic resonance imaging, signal-averaged ECG, exercise testing, drug challenge, and selective electrophysiological testing. Diagnostic criteria were based on accepted criteria or provocation of the characteristic clinical features for long-QT syndrome, catecholaminergic polymorphic ventricular tachycardia, Brugada syndrome, early repolarization, arrhythmogenic right ventricular cardiomyopathy, coronary spasm, and myocarditis. Sixty-three patients in 9 centers were enrolled (age 43.0+/-13.4 years, 29 women). A diagnosis was obtained in 35 patients (56%): Long-QT syndrome in 8, catecholaminergic polymorphic ventricular tachycardia in 8, arrhythmogenic right ventricular cardiomyopathy in 6, early repolarization in 5, coronary spasm in 4, Brugada syndrome in 3, and myocarditis in 1. Targeted genetic testing demonstrated evidence of causative mutations in 9 (47%) of 19 patients. Screening of 64 family members of these patients identified 15 affected individuals who were treated (24%). The remaining 28 patients (44%) were considered to have idiopathic ventricular fibrillation.</AbstractText>Systematic clinical testing, including drug provocation and advanced imaging, results in unmasking of the cause of apparently unexplained cardiac arrest in >50% of patients. This approach assists in directing genetic testing to diagnose genetically mediated arrhythmia syndromes, which results in successful family screening.</AbstractText> |
6,475 | Low frequency component in systolic arterial pressure variability in patients with persistent atrial fibrillation. | Atrial fibrillation (AF) is a common arrhythmia characterized by irregular ventricular response. During AF, beat-to-beat variability of arterial pressure (AP) is increased because of continuous changes in filling time, stroke volume and contractility. Only a few studies have analyzed short-term AP variability during AF but they were mainly focused on the effects of respiration. We therefore analyzed short-term systolic (S), diastolic (D) and mean (M) AP variability by autoregressive method and an FFT-based spectral estimation (Welch periodogram) in 26 patients with persistent AF before and after restoration of sinus rhythm by electrical cardioversion. A low frequency (LF) component (central frequency 0.07+/-0.02 Hz, mean+/-standard deviation) of SAP variability was observed in 23 out of 26 patients during AF. Frequency analysis of DAP and MAP also showed a LF component with a central frequency of 0.08+/-0.03 Hz (20 patients) and 0.07+/-0.03 Hz (25 patients), respectively. After recovery of sinus rhythm, we found significant reduction in mean SAP, DAP and MAP variability in all frequency bands. Squared coherence between SAP and heart rate variability after recovery of sinus rhythm revealed a weak and strong coupling within, respectively, LF and HF frequency bands. These data indicate that in patients with AF, in spite of an absence of rhythmical oscillation in RR interval time series, it is possible to observe a LF component in SAP, DAP and MAP variability signals. These 0.1 Hz fluctuations reflect the influence of the sympathetic fibres acting on the cardiovascular system. |
6,476 | A simple automated stimulator of mechanically induced arrhythmias in the isolated rat heart. | Transient stretching of the ventricle can trigger arrhythmias and evoke ventricular fibrillation, especially when the stimulation occurs in the vulnerable period. To explore the sensitivity of small hearts we used a commercial pressure servo to study the kinetic relationship of left ventricular pressure to excitability and arrhythmias in the rat heart. Stimulation protocols were readily composed on the computer and programmed to vary the stimulus amplitude and timing relative to pacing. The pressure-induced premature ventricular excitations were similar to those observed in larger hearts, but the convenience of using small hearts allows the use of inexpensive transgenic animals to explore the molecular basis of transduction. |
6,477 | A broad complex tachycardia with conflicting information from pacing manoeuvres. | A patient with a biventricular implantable cardioverter defibrillator for heart failure had a recurrent broad complex tachycardia and underwent electrophysiologic testing. The tachycardia was induced only with ventricular pacing. There was a 1:1 atrioventricular relationship with simultaneous atrial and ventricular activation. However, atrial pacing during tachycardia suggested atrial dissociation from the circuit. The findings, potential mechanisms, and treatment are discussed. |
6,478 | Effects of recombinant human granulocyte colony-stimulating factor (filgrastim) on ECG parameters in neutropenic patients: a single-centre, prospective study. | Human granulocyte colony-stimulating factor (G-CSF) is a haematopoietic hormone that promotes the growth, proliferation, differentiation and maturation of neutrophil precursors. Filgrastim is a recombinant human G-CSF. Myocardial infarction, atrial fibrillation and arrhythmia have been reported in several patients with malignancy receiving filgrastim, but a causal relationship with the drug has not been established. The purpose of this study was to investigate the changes in ECG parameters in neutropenic patients during treatment with filgrastim.</AbstractText>This was a single-centre, prospective study carried out in a hospital emergency room. Patients with neutropenia and malignancy who were required to receive filgrastim were eligible for the study. After a reference ECG had been obtained, filgrastim was administered to all patients at a dose of 5 microg/kg/day subcutaneously for 2 days. Follow-up ECGs were then obtained at 12-hourly intervals. Continuous telemetric monitoring was conducted throughout hospitalization.</AbstractText>Serial ECG parameters were compared in 102 patients. There were no statistically significant differences between baseline and follow-up ECG measurements of rhythm, P-wave duration, PR interval, QRS-wave duration, corrected QT (QTc) interval, ECG axis, premature supraventricular events, ventricular arrhythmia, R-wave progression, right bundle branch block or left bundle branch block. There was a significant reduction in mean heart rate in subsequent ECGs compared with baseline (p < 0.05).</AbstractText>This study did not demonstrate any ECG changes other than a significant reduction in mean heart rate in this selected population of neutropenic patients given 2 days' treatment with subcutaneous 5 microg/kg/day of filgrastim.</AbstractText> |
6,479 | Pleiotropic effects of statins in atrial fibrillation patients: the evidence. | Atrial fibrillation (AF) is the most common sustained arrhythmia in clinical practice. The understanding of the pathophysiology of AF has changed during the last several decades, and a significant role of inflammation and of the renin-angiotensin-aldosterone system has been postulated both experimentally and clinically. There is emerging evidence of an association between inflammation and AF, and mounting evidence links increased C-reactive protein levels not only to already existing AF but also to the risk of developing future AF. The beneficial effects of statins on AF have been reported in several studies. Several randomized clinical and large observational studies have shown similar result that show the beneficial effect of statins in AF. In clinical studies, statins were considered effective in preventing AF after electrical cardioversion, post-ablation, and after permanent pacemaker and implantable cardioverter defibrillator insertion. The antiarrhythmic mechanisms of statins regarding AF prevention in patients with heart failure are still not clear. Perioperative statin use has been associated with favorable postoperative outcome in both cardiovascular and noncardiovascular conditions. Despite a growing body of evidence that drugs with anti-inflammatory properties such as statins may prevent AF, the observed positive effects of statins on the burden of AF appeared to be independent of their cholesterol-reducing properties. However, further data from large-scale randomized trials are clearly needed. |
6,480 | Clinical impact of atrial fibrillation in patients with hypertrophic cardiomyopathy. Results from Kochi RYOMA Study. | There have been few studies of the clinical features of hypertrophic cardiomyopathy (HCM) in a community-based patient cohort in Japan.</AbstractText>Cardiomyopathy registration was established in Kochi Prefecture and named the Kochi RYOMA (registry of myocardial diseases) study, consisting of 9 hospitals that registered 261 patients with a diagnosis of HCM. At registration, 74 patients (28%) had documented paroxysmal or chronic atrial fibrillation (AF). Although most patients (93%) were in New York Heart Association (NYHA) class I or II, 17 of the 18 patients in NYHA III had AF; 37 of the 74 patients with AF suffered from morbid events (embolism and/or heart failure (HF) admission), and 15 of 19 patients with embolic events had AF prior to or at the time of embolism. Of the 29 patients who had a history of HF admission, 8 had left ventricular systolic dysfunction, and the other 21 patients were hospitalized because of diastolic HF. AF occurred prior to HF in 20 of those 21 patients. Furthermore, 19 of those 20 patients with AF and diastolic HF were hospitalized within 1 year after detection of AF.</AbstractText>In an unselected regional registry, AF was the major determinant of clinical deteriorations in patients with HCM.</AbstractText> |
6,481 | Ventricular rhythm in atrial fibrillation under anaesthetic infusion with propofol. | Changes in patients' autonomic tone and specific pharmacologic interventions may modify the ventricular response (actual heart rate) during atrial fibrillation (AF). Hypnotic agents such as propofol may modify autonomic balance as they promote a sedative state. It has been shown that propofol slightly slows atrial fibrillatory activity, but the net global effect on the ventricular response remains unknown. We aimed to evaluate in patients in AF the effect of a propofol bolus on the ventricular rate and regularity at ECG. We analysed the possible relation with local atrial fibrillatory activities, as ratios between atrial and ventricular rates (AVRs), analysing atrial activity from intracardiac electrograms at the free wall of the right and left atria and at the interatrial septum. We compared data at the baseline and after complete hypnosis. Propofol was associated with a more homogeneous ventricular response and lower AVR values at the interatrial septum. |
6,482 | Response to intravenous ajmaline: a retrospective analysis of 677 ajmaline challenges. | The diagnostic type I ECG in Brugada syndrome (BS) is often concealed and fluctuates between the diagnostic and non-diagnostic pattern. Challenge with intravenous ajmaline is used to unmask the diagnostic Brugada ECG. The aim of this study was to evaluate the safety of the test and to identify predictors for the response to an intravenous ajmaline challenge.</AbstractText>In four tertiary referral centres, 677 consecutive patients underwent an intravenous ajmaline challenge for diagnosis or exclusion of BS in accordance with the recommendations of the Brugada consensus conferences. Two hundred and sixty-two ajmaline challenges (39%) were positive. Male gender, familial BS, sudden cardiac arrest (SCA), first-degree AV-block, basal saddleback type ECG, and basal right bundle branch block were identified as predictors for a positive ajmaline challenge. A predictor for negative ajmaline test was the absence of ST-segment elevation at baseline. Six of 12 patients who had experienced SCA, and five of 25 patients with a familial sudden death exhibited a positive response to ajmaline. Only one patient (0.15%) developed sustained ventricular tachyarrhythmias (ventricular fibrillation) during ajmaline challenge, which was terminated by a single external defibrillator shock.</AbstractText>Ajmaline challenge is a safe procedure to unmask the electrocardiographic pattern of BS. Electrocardiographic and clinical parameters were identified to predict patients' response to ajmaline. The results of this study guide the clinician in which setting an ajmaline challenge is an appropriate diagnostic step.</AbstractText> |
6,483 | Electrophysiological findings in patients with isolated left ventricular non-compaction. | Patients with isolated left ventricular non-compaction (IVNC) are at high risk for developing ventricular tachyarrhythmias. However, no analysis of invasive electrophysiological (EP) findings in these patients has yet been performed.</AbstractText>We performed a retrospective analysis of EP findings in 24 patients with IVNC. Ventricular tachyarrhythmias were inducible in nine patients; of these, two patients had sustained monomorphic ventricular tachycardia (VT) and two patients had ventricular fibrillation. No specific electrocardiographic or echocardiographic finding was predictive of VT inducibility. Three of the 9 patients with inducible VT experienced ventricular tachyarrhythmias during the follow-up of 61.4+/-50 months, whereas no tachyarrhythmias or sudden deaths were noted in 12 patients without inducible VT during the follow-up of 30+/-19 months (3 patients in the latter group were lost to follow-up). Supraventricular tachyarrhythmias were inducible in seven patients.</AbstractText>Our present study provides the first comprehensive analysis of EP findings in patients with IVNC. Ventricular and supraventricular arrhythmias can readily be induced in these patients, whereas the inducibility of a sustained monomorphic VT is relatively low. Further studies including long-term follow-up are required to investigate the role of EP testing for arrhythmic risk stratification in these patients.</AbstractText> |
6,484 | The mode of death in the non-heart-beating donor has an impact on lung graft quality. | We hypothesised that the agonal phase prior to cardiac death may negatively influence the quality of the pulmonary graft recovered from non-heart-beating donors (NHBDs). Different modes of death were compared in an experimental model.</AbstractText>Non-heparinised pigs were divided into three groups (n=6 per group). Animals in group I [FIB] were sacrificed by ventricular fibrillation resulting in immediate circulatory arrest. In group II [EXS], animals were exsanguinated (45+/-11 min). In group III [HYP], hypoxic cardiac arrest (13+/-3 min) was induced by disconnecting the animal from the ventilator. Blood samples were taken pre-mortem in HYP and EXS for measurement of catecholamine levels. After 1 h of in situ warm ischaemia, unflushed lungs were explanted and stored for 3 h (4 degrees C). Left lung performance was then tested during 60 min in our ex vivo reperfusion model. Total protein concentration in bronchial lavage fluid was measured at the end of reperfusion.</AbstractText>Pre-mortem noradrenalin (mcg l(-1)) concentration (baseline: 0.03+/-0) increased to a higher level in HYP (50+/-8) vs EXS (15+/-3); p=0.0074. PO(2) (mmHg) at 60 min of reperfusion was significantly worse in HYP compared to FIB (445+/-64 vs 621+/-25; p<0.05), but not to EXS (563+/-51). Pulmonary vascular resistance (dynes s cm(-5)) was initially higher in EXS (p<0.001) and HYP (NS) vs FIB (15824+/-5052 and 8557+/-4933 vs 1482+/-61, respectively) but normalised thereafter. Wet-to-dry weight ratio was higher in HYP compared to FIB (5.2+/-0.3 vs 4.7+/-0.2, p=0.041), but not to EXS (4.9+/-0.2). Total protein (g l(-1)) concentration was higher, although not significant in HYP and EXS vs FIB (18+/-6 and 13+/-4 vs 4.5+/-1.3, respectively).</AbstractText>Pre-mortem agonal phase in the NHBD induces a sympathetic storm leading to capillary leak with pulmonary oedema and reduced oxygenation upon reperfusion. Graft quality appears inferior in NHBD lungs when recovered in controlled (HYP) vs uncontrolled (EXS and FIB) setting.</AbstractText> |
6,485 | Ventricular tachycardia and ventricular fibrillation.<Pagination><StartPage>801</StartPage><EndPage>809</EndPage><MedlinePgn>801-9</MedlinePgn></Pagination><ELocationID EIdType="doi" ValidYN="Y">10.1586/erc.09.69</ELocationID><Abstract><AbstractText>Ventricular tachycardia and ventricular fibrillation are the most important causes of sudden cardiac death (SCD), particularly in those with structural heart disease and reduced left ventricular function. It is important to distinguish ventricular tachycardia from supraventricular tachycardia. A wide spectrum of ventricular arrhythmias exists, from those where the heart is structurally normal to those with structural heart disease. Each entity has a distinctive pathophysiology, treatment plan and prognostic outcome. Treatment modalities include simple beta-blockade to implantation of implantable cardiac defibrillator and ablative approaches. In general, those ventricular arrhythmias associated with a structurally normal heart are more benign than those associated with structural heart disease.</AbstractText></Abstract><AuthorList CompleteYN="Y"><Author ValidYN="Y"><LastName>Srivathsan</LastName><ForeName>Komandoor</ForeName><Initials>K</Initials><AffiliationInfo><Affiliation>Cardiovascular Diseases, Mayo Clinic, Scottsdale, AZ 85255, USA.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Ng</LastName><ForeName>Daniel W C</ForeName><Initials>DW</Initials></Author><Author ValidYN="Y"><LastName>Mookadam</LastName><ForeName>Farouk</ForeName><Initials>F</Initials></Author></AuthorList><Language>eng</Language><PublicationTypeList><PublicationType UI="D016428">Journal Article</PublicationType><PublicationType UI="D016454">Review</PublicationType></PublicationTypeList></Article><MedlineJournalInfo><Country>England</Country><MedlineTA>Expert Rev Cardiovasc Ther</MedlineTA><NlmUniqueID>101182328</NlmUniqueID><ISSNLinking>1477-9072</ISSNLinking></MedlineJournalInfo><ChemicalList><Chemical><RegistryNumber>0</RegistryNumber><NameOfSubstance UI="D000889">Anti-Arrhythmia Agents</NameOfSubstance></Chemical></ChemicalList><CitationSubset>IM</CitationSubset><MeshHeadingList><MeshHeading><DescriptorName UI="D000889" MajorTopicYN="N">Anti-Arrhythmia Agents</DescriptorName><QualifierName UI="Q000627" MajorTopicYN="N">therapeutic use</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D017115" MajorTopicYN="N">Catheter Ablation</DescriptorName><QualifierName UI="Q000379" MajorTopicYN="N">methods</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D016757" MajorTopicYN="N">Death, Sudden, Cardiac</DescriptorName><QualifierName UI="Q000209" MajorTopicYN="N">etiology</QualifierName><QualifierName UI="Q000517" MajorTopicYN="Y">prevention & control</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D017147" MajorTopicYN="N">Defibrillators, Implantable</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D006331" MajorTopicYN="N">Heart Diseases</DescriptorName><QualifierName UI="Q000503" MajorTopicYN="N">physiopathology</QualifierName><QualifierName UI="Q000628" MajorTopicYN="N">therapy</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D006801" MajorTopicYN="N">Humans</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D011379" MajorTopicYN="N">Prognosis</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D017180" MajorTopicYN="N">Tachycardia, Ventricular</DescriptorName><QualifierName UI="Q000175" MajorTopicYN="N">diagnosis</QualifierName><QualifierName UI="Q000503" MajorTopicYN="N">physiopathology</QualifierName><QualifierName UI="Q000628" MajorTopicYN="Y">therapy</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D018487" MajorTopicYN="N">Ventricular Dysfunction, Left</DescriptorName><QualifierName UI="Q000503" MajorTopicYN="N">physiopathology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D014693" MajorTopicYN="N">Ventricular Fibrillation</DescriptorName><QualifierName UI="Q000175" MajorTopicYN="N">diagnosis</QualifierName><QualifierName UI="Q000503" MajorTopicYN="N">physiopathology</QualifierName><QualifierName UI="Q000628" MajorTopicYN="Y">therapy</QualifierName></MeshHeading></MeshHeadingList><NumberOfReferences>64</NumberOfReferences></MedlineCitation><PubmedData><History><PubMedPubDate PubStatus="entrez"><Year>2009</Year><Month>7</Month><Day>11</Day><Hour>9</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="pubmed"><Year>2009</Year><Month>7</Month><Day>11</Day><Hour>9</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="medline"><Year>2009</Year><Month>9</Month><Day>26</Day><Hour>6</Hour><Minute>0</Minute></PubMedPubDate></History><PublicationStatus>ppublish</PublicationStatus><ArticleIdList><ArticleId IdType="pubmed">19589116</ArticleId><ArticleId IdType="doi">10.1586/erc.09.69</ArticleId></ArticleIdList></PubmedData></PubmedArticle><PubmedArticle><MedlineCitation Status="MEDLINE" Owner="NLM"><PMID Version="1">19588586</PMID><DateCompleted><Year>2009</Year><Month>09</Month><Day>10</Day></DateCompleted><DateRevised><Year>2016</Year><Month>11</Month><Day>25</Day></DateRevised><Article PubModel="Print"><Journal><ISSN IssnType="Print">0023-1207</ISSN><JournalIssue CitedMedium="Print"><Issue>4</Issue><PubDate><Year>2009</Year></PubDate></JournalIssue><Title>Khirurgiia</Title><ISOAbbreviation>Khirurgiia (Mosk)</ISOAbbreviation></Journal>[Acute right ventricular perforation with the pacemaker electrode]. | Ventricular tachycardia and ventricular fibrillation are the most important causes of sudden cardiac death (SCD), particularly in those with structural heart disease and reduced left ventricular function. It is important to distinguish ventricular tachycardia from supraventricular tachycardia. A wide spectrum of ventricular arrhythmias exists, from those where the heart is structurally normal to those with structural heart disease. Each entity has a distinctive pathophysiology, treatment plan and prognostic outcome. Treatment modalities include simple beta-blockade to implantation of implantable cardiac defibrillator and ablative approaches. In general, those ventricular arrhythmias associated with a structurally normal heart are more benign than those associated with structural heart disease. |
6,486 | Dose-related shortening of ventricular tachycardia cycle length after administration of the KATP channel opener bimakalim in a 4-day-old chronic infarct anesthetized pig model. | Potassium channel openers are known to act on potassium ATP-dependent channels in cardiac tissue. Such agents may exacerbate acceleration of acute ischemia-induced ventricular repolarization and aggravate arrhythmias. To test whether activation of K( ATP) channels during the healing period of myocardial infarction (MI) can still influence the electrophysiologic properties and the type of inducible arrhythmias, we investigated the effects of bimakalim (BIM) on sustained ventricular tachycardia (VT) 4 days after ligation of the left anterior descending (LAD) coronary artery in pigs. Programmed stimulation was performed to elicit VT prior to and after intravenous (IV) BIM. Combination monophasic action potential (MAP)/PACING catheters were used to enable simultaneous ventricular MAP recording and pacing. Ventricular effective refractory period (ERP) and MAP duration determined at 50% and 90% repolarization were measured prior to and after BIM. After completion of baseline measurements, BIM was consecutively given at 0.5, 1, and 3 mg/kg bolus followed by 0.025, 0.05, and 0.1 mg/kg per minute maintenance infusion, respectively. From a total of 23 pigs subjected to LAD ligation, 4 animals succumbed to infarction and the remaining 19 animals were studied by programmed stimulation. Only animals that exhibited reproducible and hemodynamically stable monomorphic VTs during control stimulation were selected for evaluation (n = 14). After the first, second, and third dose of BIM, the mean VT rate was increased by 6%, 14% (P <. 01), and 47% (P < .001) compared to control values, respectively. Ventricular ERP and repolarization were significantly shortened only by the second and third dose of BIM. Of 14 pigs receiving the highest BIM dosage, 3 revealed polymorphic VTs degenerating into ventricular fibrillation (VF). Our data suggest that high BIM doses may lead to faster and more aggressive pacing-induced reentrant VTs after subacute MI. This is consistent with the drug-induced acceleration of ventricular repolarization with shortening of MAP duration and refractoriness. |
6,487 | Temporary epicardial ventricular stimulation in patients with atrial fibrillation: acute effects of ventricular pacing site on bypass graft flows. | Data on coronary artery bypass grafts flows in patients with atrial fibrillation (AF) requiring epicardial ventricular pacing is lacking. This study aimed to evaluate the optimal epicardial ventricular pacing site in patients with AF following coronary artery bypass surgery (CABG).</AbstractText>In 23 consecutive patients (mean age = 69.2 +/- 1.9 years, gender = 62% male, ejection fraction [EF]= 50.4 +/- 2.1%) monoventricular stimulations (VVI) were tested with a constant pacing rate of 100 bpm. The impact of ventricular pacing on bypass graft flow (transit-time flow probe) and pulsatility index (PI) were measured after lead placement on the mid paraseptal region of the right (RVPS) and the left (LVPS) ventricle, on the right inferior wall (RVIW), and on the right ventricular outflow tract (RVOT). In addition, hemodynamic parameters were measured. Patients served as their own control.</AbstractText>Comparison of all tested pacing locations revealed that RVOT stimulation provided the highest bypass grafts flows (59.9 +/- 6.1 mL/min) and PI (2.2 +/- 0.1) when compared with RVPS (51.3 +/- 4.7 mL/min, PI = 2.6 +/- 0.2), RVIW (54.0 +/- 5.1 mL/m; PI = 2.4 +/- 0.2), and LVPS (53.1 +/- 4.5 mL/min; PI = 2.3 +/- 0.1), respectively (p < 0.05). When analyzing patients according to their preoperative LV function (group I = EF > 50%; group II = EF < 50%), higher bypass graft flows were observed with RVOT pacing in patients with lower EF (p = n.s.).</AbstractText>Temporary RVOT pacing facilitates optimal bypass graft flows when compared with other ventricular pacing sites and should be the preferred method of temporary pacing in cardiac surgery patients with AF. Especially in patients with low EF following CABG, RVOT pacing may improve myocardial oxygen conditions for the ischemic myocardium and enhance graft patency in the early postoperative period.</AbstractText> |
6,488 | Treatment of asystole and PEA. | Recent reports consistently point to a substantial decline in the incidence of ventricular fibrillation (VF) as the initial rhythm observed by Emergency Medical Service (EMS) responders and a complementary increase in pulseless electrical activity (PEA) and asystole. Historically, efforts at improving survival have focused primarily on patients found in VF. Consequently, the approach for other patients has included frequent pauses in cardiopulmonary resuscitation (CPR) to check for VF followed by shock when VF is observed. However, the "yield" of survivors comes largely from the non-shocked patients. Therefore, it is critical that we start evaluating treatments specifically for the PEA and asystole groups. |
6,489 | Effect and mechanism of esmolol given during cardiopulmonary resuscitation in a porcine ventricular fibrillation model. | The aim of the study was to investigate the effect on calcium cycling protein and electrical restitution of beta(1)-adrenergic receptor antagonist esmolol administered during cardiopulmonary resuscitation in the porcine ventricular fibrillation model.</AbstractText>Ventricular fibrillation untreated for four minutes was induced by dynamic steady state pacing protocol in 40 healthy male pigs, in which local unipolar electrograms were recorded using one 10-electrode catheter that was sutured to the left ventricular epicardium. During CPR, animals were randomized into two groups to receive saline as placebo or esmolol after two standard doses of epinephrine. At post-resuscitation 2-h, six pigs were randomly selected from each group and the second VF induction was performed. Local activation-recovery intervals (ARI) restitutions and the VF inducibility between control group and esmolol group were compared. Western blotting was performed to determine expression of Ca(2+)/calmodulin-dependent protein kinase IIdelta(CaMKIIdelta) and cardiac ryanodine receptor (RyR2) protein, and their phosphorylation status.</AbstractText>Injection of esmolol combined with epinephrine during CPR significantly decreased recurrent rate of ventricular fibrillation during 2-h post-resuscitation, meanwhile it has no adverse affect on the restore of spontaneous circulation. Esmolol significantly flattened ARI restitution slope, lessened regional difference of ARI restitution, decreased the VF inducibility, and alleviated CaMKIIdelta hyper-activation and RyR2 hyper-phosphorylation.</AbstractText>Esmolol given during CPR has significant effects on modulating electrical restitution property and intracellular calcium handling, which contributes the most important reasons why beta(1)-blockade significantly reduced the onset and maintenance of VF.</AbstractText> |
6,490 | Subarachnoid haemorrhage as a cause of out-of-hospital cardiac arrest: a prospective computed tomography study. | Aneurysmal subarachnoid haemorrhage (SAH) is a relatively common cause of out-of-hospital cardiac arrest (OHCA). Early identification of SAH-induced OHCA with the use of brain computed tomography (CT) scan obtained immediately after resuscitation may help emergency physicians make therapeutic decision as quickly as they can.</AbstractText>During the 4-year observation period, brain CT scan was obtained prospectively in 142 witnessed non-traumatic OHCA survivors who remained haemodynamically stable after resuscitation. Demographics and clinical characteristics of SAH-induced OHCA survivors were compared with those with "negative" CT finding.</AbstractText>Brain CT scan was feasible with an average door-to-CT time of 40.0 min. SAH was found in 16.2% of the 142 OHCA survivors. Compared with 116 survivors who were negative for SAH, SAH-induced OHCA survivors were significantly more likely to be female, to have experienced a sudden headache, and trended to have achieved return of spontaneous circulation (ROSC) prior to arrival in the emergency department less frequently. Ventricular fibrillation (VF) was significantly less likely to be seen in SAH-induced than SAH-negative OHCA (OR, 0.06; 95% CI, 0.01-0.46). Similarly, Cardiac Trop-T assay was significantly less likely to be positive in SAH-induced OHCA (OR, 0.08; 95% CI, 0.01-0.61).</AbstractText>Aneurysmal SAH causes OHCA more frequently than had been believed. Immediate brain CT scan may particularly be useful in excluding SAH-induced OHCA from thrombolytic trial enrollment, for whom the use of thrombolytics is contraindicated. The low VF incidence suggests that VF by itself may not be a common cause of SAH-induced OHCA.</AbstractText> |
6,491 | Isolated ventricular noncompaction mimicking arrhythmogenic right ventricular cardiomyopathy--a study of nine patients. | Isolated ventricular noncompaction is considered to predominantly affect the left ventricle. It is characterized by increased left ventricular wall thickness and deep intertrabecular recesses with to-and-fro blood flow that remains in continuity with the ventricular flow. Aim of the study was to present a group of patients with isolated noncompaction of both ventricles mimicking arrhythmogenic right ventricular cardiomyopathy (ARVC).</AbstractText>Reported group consisted of 9 pts initially diagnosed with ARVC (mean age 37.9 y, 7 male), who underwent basic clinical evaluation. CMR was performed in 8 pts, cardiac catheterization in 2 pts and endomyocardial biopsy in 2 pts. Mean age at presentation of first symptoms was 23.5 y (5-44 y). Heart failure symptoms were observed in 4 pts, atrial fibrillation in 3 pts, ventricular tachycardia in 2 pts (polymorphic--in 2 pts) and syncope in 3 pts. Final diagnosis of noncompaction was established according to generally accepted criteria.</AbstractText>Morphologic and/or functional changes in the right ventricle were seen in 9 pts (100%): enlargement and hypertrabeculation of the right ventricle in all pts, global hypokinesis in 4 pts, focal wall motion abnormalities and/or bulges typical for ARVC in 5 pts. Two pts had significant tricuspid regurgitation. Endomyocardial biopsy (2 pts) showed abnormal thick endocardium, interstitial fibrosis, myocardial damage and lymphocyte infiltration.</AbstractText>1) Noncompaction of ventricular myocardium should be considered during the evaluation of right ventricular cardiomyopathies with excessive trabeculation. 2) In problematic cases Task Force criteria for ARVC should be used to improve the accuracy of assessment.</AbstractText>Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
6,492 | Cardiovascular magnetic resonance guided electrophysiology studies. | Catheter ablation is a first line treatment for many cardiac arrhythmias and is generally performed under x-ray fluoroscopy guidance. However, current techniques for ablating complex arrhythmias such as atrial fibrillation and ventricular tachycardia are associated with suboptimal success rates and prolonged radiation exposure. Pre-procedure 3D CMR has improved understanding of the anatomic basis of complex arrhythmias and is being used for planning and guidance of ablation procedures. A particular strength of CMR compared to other imaging modalities is the ability to visualize ablation lesions. Post-procedure CMR is now being applied to assess ablation lesion location and permanence with the goal of indentifying factors leading to procedure success and failure. In the future, intra-procedure real-time CMR, together with the ability to image complex 3-D arrhythmogenic anatomy and target additional ablation to regions of incomplete lesion formation, may allow for more successful treatment of even complex arrhythmias without exposure to ionizing radiation. Development of clinical grade CMR compatible electrophysiology devices is required to transition intra-procedure CMR from pre-clinical studies to more routine use in patients. |
6,493 | Sleep-disordered breathing in patients with atrial fibrillation and normal systolic left ventricular function. | Obstructive sleep apnea (OSA) is more common in patients with atrial fibrillation (AFib). Recently, an additional association between central sleep apnea/Cheyne-Stokes respiration (CSA/CSR) and AFib has been described. The aim of this study was to investigate the prevalence and type of sleep-disordered breathing in patients with AFib and normal systolic left ventricular function.</AbstractText>150 patients (110 men and 40 women, aged 66.1 +/- 1.7 years) underwent cardiorespiratory polygraphy, capillary blood gas analysis, measurement of NT-proBNP, and echocardiography to determine the diameter of the left atrium (LAD) and the peak systolic pulmonary artery pressure (PAP).</AbstractText>Sleep-disordered breathing was documented in 74% of all patients with AFib (43% had OSA and 31% had CSA/CSR). Patients with CSA/CSR had a higher PAP, a higher apnea-hypopnea index, a greater LAD, and a lower capillary blood pCO(2) than patients with OSA.</AbstractText>Patients with AFib were found to have not only a high prevalence of obstructive sleep apnea, as has been described previously, but also a high prevalence of CSA/CSR. It remains unknown whether CSA/CSR is more common in AFib because of diastolic dysfunction or whether phenomena associated with CSA/CSR predispose to AFib. Further research on this question is needed.</AbstractText> |
6,494 | Long-term mortality predictors in patients with chronic bifascicular block. | To evaluate the long-term mortality rate and to determine independent mortality risk factors in patients with bifascicular block (BFB). Patients with BFB are known to have a higher mortality risk than the general population, not only related to progression to atrio-ventricular block but also due to the presence of malignant ventricular arrhythmias. Previous observational and epidemiological studies including a high proportion of patients with structural heart disease have shown an important cardiac mortality rate and may not reflect the real outcome of patients with BFB.</AbstractText>From March 1998 until December 2006, we prospectively studied 259 consecutive BFB patients, 213 (82%) of whom presenting with syncope/pre-syncope, undergoing electrophysiological study. After a median follow-up of 4.5 years (P25:2.16-P75:6.41), 53 patients (20.1%) died, 19 (7%) of whom due to cardiac aetiology. Independent total mortality predictors were age [hazard ratio (HR) 1.04, 95% confidence interval (CI) 1.01-1.09], NYHA class>or=II (HR 2.17, 95% CI 1.05-4.5), atrial fibrillation (HR 2.96, 95% CI 1.1-7.92), and renal dysfunction (HR 4.26, 95% CI 2.04-9.01). An NYHA class of >or=II (HR 5.45, 95% CI 2.01-14.82) and renal failure (HR 3.82, 95% CI 1.21-12.06) were independent predictors of cardiac mortality. No independent predictors of arrhythmic death were found.</AbstractText>Total mortality, especially of cardiac cause, is lower than previously described in BFB patients. Advanced NYHA class and renal failure are predictors of cardiac mortality.</AbstractText> |
6,495 | A multicentre evaluation of the safety of intracoronary optical coherence tomography. | Optical coherence tomography (OCT) is increasingly being applied to the coronary arteries. However, the risks associated with the imaging procedure are not yet well defined. The purpose of the present multicentre registry was to assess the acute complications associated with the clinical use of intra-coronary OCT in a large number of patients.</AbstractText>Consecutive patients from six centres who had OCT examination were retrospectively included. All adverse events and complications, even if transient, were noted. Risks were categorised into: 1) self-limiting 2) major complications including major adverse cardiac events (MACE) and 3) mechanical device failure. A total of 468 patients underwent OCT examination for evaluation of: plaque (40.0%), percutaneous coronary intervention (28.2%) or follow-up stent tissue coverage (31.8%). OCT was performed using a non-occlusive flush technique in 45.3% with a mean contrast volume of 36.6+/-9.4ml. Transient chest pain and QRS widening/ST-depression/elevation were observed in 47.6% and 45.5% respectively. Major complications included five (1.1%) cases of ventricular fibrillation due to balloon occlusion and/or deep guide catheter intubation, 3 (0.6%) cases of air embolism and one case of vessel dissection (0.2%). There were no cases of coronary spasm or MACE during or within the 24 hour period following OCT examination.</AbstractText>OCT is a specialised technique with a relatively steep learning curve. Major complications are uncommon and can be minimised with careful procedural planning and having an awareness of the potential contributory risks, especially deep guide catheter intubation during contrast flushing. Upcoming developments will make OCT more practical and less procedurally demanding, also potentially conserving contrast volume considerably.</AbstractText> |
6,496 | Predictors of six-month major adverse cardiac events in 30-day survivors after acute myocardial infarction (from the Korea Acute Myocardial Infarction Registry). | Little is known about risk factors for 6-month major adverse cardiac events (MACEs) in 30-day survivors after acute myocardial infarction (AMI). We investigated predictors of 6-month MACE in 30-day survivors after MI from the Korea Acute Myocardial Infarction Registry (KAMIR). From November 2005 to January 2008, 9,706 patients (6,983 men, mean age 64.0 +/- 12.4 years) who survived >30 days after AMI were analyzed. The primary end point was 6-month MACEs including death, MI, and revascularization. During 6-month follow-up, 317 patients (3.2%) had MACEs including 66 (0.6%) deaths, 23 (0.2%) recurrent MIs, and 218 (2.2%) revascularizations. In multivariate logistic regression analysis, factors reflecting demographics (body mass index), severity of left ventricular systolic dysfunction (Killip class >I, in-hospital cardiogenic shock, use of intra-aortic balloon pump), residual myocardial ischemia (previous coronary heart disease, multivessel disease), and electrical instability (ventricular tachycardia/ventricular fibrillation on admission) were independent predictors of 6-month MACEs after adjustment for clinical, angiographic, and procedural data. Plasma level of N-terminal pro-B-type natriuretic peptide provided an additional prognostic value predicting 6-month MACEs. In conclusion, this study provides useful prognostic information for clinicians to advise patients who have survived the acute phase of MI. More intensive management is needed in survivors after MI with these high-risk features. |
6,497 | Ventricular arrhythmia following alcohol septal ablation for obstructive hypertrophic cardiomyopathy. | We sought to assess the risk of sudden cardiac death (SCD) and ventricular arrhythmia after alcohol septal ablation (ASA) for obstructive hypertrophic cardiomyopathy. ASA is a nonsurgical alternative to septal myectomy for treatment of symptomatic, drug-refractory, obstructive hypertrophic cardiomyopathy. The effect of ASA on ventricular arrhythmia risk is not well established. We examined the rates of SCD among 89 patients treated with ASA. The secondary end point was ventricular tachycardia/ventricular fibrillation (VT/VF), appropriate implantable cardioverter defibrillator (ICD) therapy, or cardiac arrest after ASA among those with implanted ICDs or permanent pacemakers (n = 42). Patients were classified as either high-risk or low-risk on the basis of established clinical indications for ICD implantation. No mortality was attributable to SCD at a mean follow-up of 5.0 +/- 2.3 years in the entire cohort. Among the 42 patients with an ICD or permanent pacemaker, 9 had documented VT/VF, cardiac arrest, or appropriate ICD therapy, resulting in an annual event rate of 4.9%/year. The annual event rate for VT/VF, cardiac arrest, or appropriate ICD therapy was 2.8%/year (4 of 29 patients) in low-risk patients and 13.4% in high-risk patients (5 of 13 patients). A 10-mm Hg increase in the immediate post-ASA gradient was associated with a hazard ratio of 2.66 for arrhythmic events (95% confidence interval 1.55 to 4.56, p <0.001). In conclusion, ASA was performed in patients with highly symptomatic, drug-refractory hypertrophic cardiomyopathy with no mortality attributable to SCD and an annual rate of VT/VF, cardiac arrest, or appropriate ICD therapy of 4.9%/year. |
6,498 | [A 10 years review of the characteristics of in-hospital ventricular fibrillation victim in a single center]. | To study the factors influencing the outcome of patients suffering from in-hospital ventricular fibrillation (IHVF), as there have been few studies focusing on this topic.</AbstractText>Patients with IHVF collected in a single cardiac center were classified into a successful group and a failure group. Data relevant to the predicting factors of the two groups were compared.</AbstractText>There were 206 events in the analysis. The most common underlining disease was coronary artery disease (CAD), especially acute myocardial infarction (AMI). On multiple logistic regression analysis, it was shown that the independent predictors for failure of defibrillation were higher NYHA class (OR 1.7, 95% CI 1.3 - 2.2, P < 0.001), higher blood potassium level (OR 2.9, 95% CI 1.9 - 4.3, P = 0.007) and adrenaline usage (OR 25.0, 95% CI 11.5 - 55.1, P < 0.001). In a AMI sub-group, 56.9% of the IHVF events occurred within the first day of AMI, and the occurrence descended with time going on within 2 weeks. Before the occurrence of IHVF, the patients with right coronary artery as the infarction related artery (IRA) often suffered from (8/9, 88.9%) bradycardia (R-R interval > 1 s), but those with left anterior descending artery as IRA often showed (8/12, 66.7%) tachycardia (RR interval < 0.6 s).</AbstractText>The common disease causing IHVF is CAD. The worse the heart function, the higher the rate of IHVF and the worse the prognosis. It IHVF not induced by hypokalemia and use of adrenaline in resuscitation predict lower successful defibrillation rate.</AbstractText> |
6,499 | Simultaneous optical mapping of intracellular free calcium and action potentials from Langendorff perfused hearts. | The cardiac action potential (AP) controls the rise and fall of intracellular free Ca2+ (Ca(i)), and thus the amplitude and kinetics of force generation. Besides excitation-contraction coupling, the reverse process where Ca(i) influences the AP through Ca(i)-dependent ionic currents has been implicated as the mechanism underlying QT alternans and cardiac arrhythmias in heart failure, ischemia/reperfusion, cardiac myopathy, myocardial infarction, congenital and drug-induced long QT syndrome, and ventricular fibrillation. The development of dual optical mapping at high spatial and temporal resolution provides a powerful tool to investigate the role of Ca(i) anomalies in eliciting cardiac arrhythmias. This unit describes experimental protocols to map APs and Ca(i) transients from perfused hearts by labeling the heart with two fluorescent dyes, one to measure transmembrane potential (Vm), the other Ca(i) transients. High spatial and temporal resolution is achieved by selecting Vm and Ca(i) probes with the same excitation but different emission wavelengths, to avoid cross-talk and mechanical components. |
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