Left ventricular function after a single large dose of verapamil.
The effects of a single large dose of verapamil on left ventricular (LV) function were evaluated noninvasively in 18 chronically hypertensive patients. Each patient was given a single oral dose of verapamil, 240 mg, before and after which arterial blood pressure was measured and an echocardiogram and a phonomechanocardiogram were obtained. Reactional symmetrical myocardial hypertrophy was seen in all patients on the first echocardiogram. Results showed that heart rate was not significantly altered, but there were significant decreases (p less than 0.01) in systolic blood pressure (183.89 to 127.56 mm Hg) and diastolic blood pressure (101.11 to 77.67 mm Hg). The following parameters were also significantly decreased (p less than 0.01): LV ejection time (294.56 to 274.22 ms), LV diastolic diameter (45.78 to 43.99 mm), percentage change in LV diameter (33 to 27.83%), mean velocity of circumferential fiber shortening (1.12 to 1.02 cir/s), posterior wall contraction velocity (40.83 to 36.28 mm/s), LV end-diastolic volume (97.78 to 86.89 cm3), ejection fraction (0.70 to 0.62), stroke volume (70 to 55 cm3) and cardiac output (4.7 to 4 liters/m). Three parameters were significantly increased (p less than 0.01): preejection period (104.06 to 112.06 ms), preejection period: LV ejection time ratio (0.35 to 0.41) and end-systolic volume (29.28 to 32.33 cm3). It is concluded that a single oral dose of verapamil, 240 mg, is highly efficient in lowering arterial blood pressure in chronically hypertensive patients and in reducing the peripheral resistance and LV performance indexes.