Gallopamil and diltiazem: a double-blind, randomized, cross-over trial in effort ischaemia

The aim of this study was to evaluate the efficacy and possibly the mechanism of action of gallopamil and diltiazem in a double-blind crossover trial in patients with effort ischaemia. Twenty male patients (mean age 57 +/- 6 years) with documented coronary atherosclerosis and exercise-induced ischaemia (ST depression greater than or equal to 0.15 mV) completed the study, which consisted of four 7 day periods. At the end of each period a multistage bicycle exercise stress test was performed under placebo (first and third periods) and randomly under gallopamil (50 mg t.i.d.) or diltiazem (90 mg t.i.d.) in the second and fourth periods. Both drugs significantly increased time to ischaemia (0.15 mV ST depression) as compared to placebo, from 7.9 +/- 1.7 min to 8.9 +/- 1.1 min (diltiazem) and 9.1 +/- 1.6 min (gallopamil) with no significant difference between the two drugs, and reduced the maximal extent of ST shift from 0.18 +/- 0.08 mV to 0.13 +/- 0.04 mV (diltiazem) and 0.12 +/- 0.05 mV (gallopamil). Analysis of the results from the whole population showed that the beneficial effect did not appear to be related to any specific parameter. Individual analysis showed that 13/20 patients under gallopamil and 13/20 under diltiazem increased time to ischaemia, while this was unchanged or reduced in the remainder. A positive correlation between changes in time to ischaemia and changes in rate x pressure product at ischaemia was found in both those administered gallopamil (R 0.80, P less than 0.01) and diltiazem (R 0.65, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)