tokens: Heart rate ( HR ) , mean arterial pressure ( MBP ) , positive rate of increase of left ventricular pressure ( + LVdP / dt ) , echocardiographically assessed left ventricular ejection fraction ( LVEF ) , and fractional shortening ( FS ) , as well as chronotropic response to isoproterenol and exercise - induced sympathetic stimulation were evaluated under baseline and posttreatment conditions .