Objective evaluation of gallopamil in patients with chronic stable angina.

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Abstract
In this double-blind, randomized placebo-controlled study the effects of two dosages of gallopamil on exercise tolerance were evaluated in 12 patients with stable effort angina. After a pre-study screening aimed at assessing the reproducibility of the exercise response, the patients entered the study which consisted of three 7-day consecutive periods during which placebo or gallopamil 50 mg t.i.d. or gallopamil 75 mg t.i.d. were administered according to a randomized sequence. 24-hour Holter monitoring and cross-sectional echocardiography were performed on the 6th and 7th day of each treatment period, respectively. On the 7th day of each treatment period, patients underwent an exercise test 2 and8h after the last administration of gallopamil or placebo. Blood samples for plasma gallopamil concentrations were taken just before each exercise test. The results were analysed using a three-way analysis of variance; intergroup differences were evaluated by the Newman-Keuls test. At 2 h, 11 patients with placebo and three with gallopamil experienced angina; both dosages of gallopamil significantly prolonged exercise time and — 1 mm time and also reduced ST segment depression and the rate-pressure product at submaximal workload. No significant change in the rate-pressure product was observed either on the appearance of 1 mm ST depression or at peak exercise. At 8 h, 11 patients with placebo and gallopamil 50 mg t.i.d. and 10 with gallopamil 75 mg t.i.d. experienced angina; although exercise time was significantly prolonged by both dosages of gallopamil, the increase in — 1 mm time and reduction of ST segment depression at submaximal workload did not reach statistical significance. No significant differences between the effects of the two dosages on exercise tolerance were observed. A weak but significant relationship between plasma levels and antiischaemic activity, expressed by the percentage increase in —1 mm time, was observed. Short episodes of isorhythmic atrioventricular dissociation were observed in two patients with both dosages of gallopamil. One patient presented an intermittent second degree Luciani- Wenchkeback atrioventricular block with gallopamil 75 mg t.i.d. Compared with placebo, no significant changes in fractional shortening or ejection fraction were observed under gallopamil therapy. In conclusion, our data show that gallopamil is clinically valuable in the treatment of stable effort angina and that the most likely mechanism by which it exerts its beneficial action is the reduction of myocardial oxygen consumption during exercise.