Comparison of the acute effects of captopril and of nifedipine on left ventricular diastolic function in elderly hypertensive patients.

The acute effects of single doses of captopril (C) 12.5 mg, of nifedipine (N) 10 mg, or of their combination (C + N) on parameters of left ventricular (LV) function were assessed in 18 elderly hypertensive subjects using radionuclide ventriculography. Blood pressure (BP) was lowered by C from 177/100 to 164/92 mmHg, by N from 177/100 to 161/91 mmHg (p less than 0.02/less than 0.05 for both C and N) and by C + N from 176/100 to 151/83 mmHg (p less than 0.01/less than 0.01). Nifedipine accelerated heart rate from 74 to 85 and C + N from 74 to 82 beats/min (p less than 0.01 in both cases), whereas C left it unchanged. Left ventricular ejection fraction (EF) was not significantly affected by either drug alone or by both drugs combined. Peak ejection rate (PER) and peak filling rate (PFR) were slightly, but not significantly, enhanced by all treatments. Captopril shortened the time to peak filling rate (TPFR) by 21 msec (p less than 0.05), N by 26 msec (p less than 0.01) and their combination by 22 msec (p less than 0.05); however, when corrected for RR interval or length of diastole, TPFR was shortened only by C (p less than 0.05). Tachycardia induced by acute administration of N may have an unwanted effect on LV diastolic function, which can be partially blunted by the concomitant administration of a converting enzyme inhibitor.