Response of blood pressure, cardiac output, peripheral resistance, and exercise performance to substitution of calcium blocker for beta-blocker plus thiazide diuretic therapy in patients with both systemic hypertension and mild stable angina.

We studied 14 patients to determine whether sustained-release diltiazem is a satisfactory long-term substitute for the combination of propranolol plus hydrochlorothiazide (HCTZ), control phase, in the treatment of systemic hypertension with coexisting chronic stable angina pectoris. All patients had either one- or two-vessel coronary disease and normal left ventricular systolic function. Measurements were made during the control phase and 4 and 8 weeks after substitution of sustained-release diltiazem. Only the sitting blood pressure was available before the control phase (pretreatment). Blood pressure and heart rate were measured with patients supine, sitting, and 5 minutes after standing. Cardiac output was measured in the supine position using a computerized Doppler system, and stroke volume, mean arterial pressure, and total systemic resistance were calculated. Symptom-limited modified Bruce protocol treadmill tests were performed to determine time to onset of 1 mm ST segment depression, time to termination of exercise, reason for cessation of exercise, and maximum rate-pressure product. The patients were initially receiving 160-240 mg/day of propranolol (40-60 mg q.i.d.) plus 25-50 mg/day of HCTZ and, subsequently, 12 of 14 had substitution with 240 mg/day (120 mg b.i.d.) of sustained-release diltiazem, and two received 360 mg/day with one of these patients also receiving 50 mg/day of HCTZ. These patients are a subset of a larger group of patients in whom the response of blood pressure alone has been previously reported. Diltiazem resulted in reduction of blood pressure equivalent to that with the propranolol plus HCTZ combination.(ABSTRACT TRUNCATED AT 250 WORDS)