Effect of diltiazem on left ventricular isovolumic relaxation time in patients with hypertrophic cardiomyopathy.

The effect of diltiazem on left ventricular isovolumic relaxation time was examined in 11 patients with hypertrophic obstructive and non-obstructive cardiomyopathy in a combined study using phonocardiograms and echocardiograms. Five to 10 min after intravenous injection of diltiazem (0.2 mg/kg, body weight), a prolonged isovolumic left ventricular relaxation time, which was measured from aortic component of the second heart sound to the mitral opening on the echocardiogram, decreased from 63.1 +/- 26.0 to 46.9 +/- 28.0 msec (p less than 0.01). This study suggests that diltiazem, one of the calcium blocking agents, may ameliorate the impaired left ventricular diastolic function in patients with hypertrophic cardiomyopathy.