The acute effects of the calcium channel blocking agent nifedipine in hypertrophic cardiomyopathy are described. Improved diastolic function was suggested by the increase in the rate of filling of the left ventricle and the fall in left ventricular end-diastolic pressure. Left ventricular relaxation time was shortened. There was a downward shift in the left ventricular pressure-echo dimension relationship, suggesting increased left ventricular distensibility. Nifedipine caused a fall in systolic, systemic blood pressure and an increase in heart rate, but no change in the cardiac index.
The reasons for the improvement in the diastolic function were thought to be systemic vasodilatation and change in left ventricular loading conditions, coronary vasodilatation with reduction of subendocardial left ventricular ischaemia and a direct myocardial effect and modification of myocardial calcium availability.