Acute left ventricular filling time and rate changes in hypertrophic cardiomyopathy after verapamil and propranolol evaluated by nuclear stethoscope.

We have undertaken the present study to evaluate the acute effects of propranolol and verapamil on the diastolic function in patients with hypertrophic cardiomyopathy. We used a non imaging isotope device, the nuclear stethoscope, that has been so far mainly employed for assessment of systolic function, although fitted for detecting diastolic filling rates and times as well. Relative cardiac output, ejection fraction, rapid and slow filling times and rates were measured in five patients suffering from hypertrophic cardiomyopathy in basal conditions and 10.20 and 30 minutes after i.v. administration for either propranolol or verapamil, with a time interval of at least 24 hours between the two acute drug studies. With respect to the baseline values only verapamil showed a significant improvement in rapid and maximum filling rates, suggesting that diastolic function is more beneficially affected by Ca-entry blockers rather than beta-blockers in hypertrophic cardiomyopathy.