[Effect of isoproterenol on left-ventricular systolic time interval in primary hypertrophic cardiomyopathy]

Left ventricular systolic time intervals were investigated before and after administration i.v. 10 micrograms of isoproterenol in a group of 12 patients with hypertrophic cardiomyopathy. Control group consisted of 10 healthy subjects. Isoproterenol shortened on hypertrophic cardiomyopathy pre-ejection periods: pre-ejection period index, isovolumetric contraction time, and Q-1. sound interval. Q-2. sound interval index did not shorten after isoproterenol what was observed in healthy subjects. Lef ventricular ejection time index lengthened little in patients and shortened in controls. These changes of left ventricular systolic time intervals suggest that isoproterenol makes difficult blood ejection from the ventricle.