EFFECTS OF CONTINUOUS INTRAVENOUS GALLOPAMIL ADMINISTRATION ON BLOOD-PRESSURE, HEART-RATE AND HOLTER-DETECTED ISCHEMIA IN ELDERLY PATIENTS WITH UNSTABLE ANGINA - A COMPARISON WITH DILTIAZEM

Background: The intravenous administration of heart rate-lowering calc ium antagonists, such as verapamil and diltiazem, has proved to be eff ective in obtaining a prompt and steady reduction of myocardial oxygen consumption in patients with unstable angina. However, elderly patien ts can be particularly susceptible to the negative inotropic and dromo tropic effects of these agents. Methods: In a randomized parallel-grou p study, we compared the effects of the verapamil derivative gallopami l (a bolus of 50 mu g/kg followed by an infusion of 0.5-0.8 mu g/kg/mi n) with those of diltiazem (a bolus of 0.1 mg/kg followed by an infusi on of 2-5 mu g/kg/min) in 39 patients aged over 70 years (median 77, r ange 70-87) with a diagnosis of unstable angina. All patients were tre ated with aspirin, heparin and nitrates during the run-in (24 h) and t he randomized (48 h) treatment periods. Holter monitoring was performe d throughout the study. Results: Both agents reduced the systolic bloo d pressure (P<0.0001 compared with baseline) and the heart rate (P<0.0 01 compared with baseline) to an equal extent in the first hour of inf usion, a reduction that was maintained during the following 48 h. Dilt iazem also reduced the diastolic blood pressure from baseline (P<0.01) , whereas gallopamil had no effect. Only one patient experienced trans ient asymptomatic hypotension, and another developed first-degree atri oventricular block with gallopamil. None of the patients developed bra dycardia or clinical signs of heart failure. During the 24 h run-in pe riod, 10 episodes of ST-segment depression (177 min) were recorded usi ng Holter monitoring in the group receiving gallopamil and 22 episodes (247 min) in those receiving diltiazem. During the 48 h of treatment, one episode (15 min) of ST-segment depression was recorded in the gal lopamil group and 17 episodes (294 min) in the diltiazem group (P<0.05 ). Conclusion: Both gallopamil and diltiazem, when administered as a c ontinuous intravenous infusion, reduced the heart rate and systolic bl ood pressure (and thus myocardial oxygen consumption) in elderly patie nts with unstable angina without producing adverse cardiac effects. Th e reduction in diastolic blood pressure observed with diltiazem, but n ot with gallopamil, might impair coronary perfusion in elderly patient s. Patients treated with gallopamil had fewer episodes of ST-segment d epression than those treated with diltiazem.