An objective comparison of verapamil and placebo in chronic stable angina

1. The efficacy of verapamil in a dose of 360 mg daily in patients with chronic stable angina pectoris was assessed by quantitative serial treadmill exercise tests and trinitrin consumption. Twenty-eight patients were investigated in a placebo-controlled, double-blind cross-over comparison of 2 weeks each, after which all were put on long-term verapamil treatment. Exercise tests were done at the end of the placebo period and after 2 and 4 weeks on verapamil. 2. On placebo, all twenty-eight patients developed angina during treadmill tests and the mean exercise time was 6.6 min (s.e.m. = 0.5 min). On verapamil, this increased to 9.2 min (s.e.m. = 0.8 min) at 2 weeks and to 11.2 (s.e.m. = 0.8 min) at 4 weeks, respectively. Trinitrin consumption showed a similar improvement. The double product and ST segment changes, analysed by on-line computer, showed a statistically significant improvement. The only side effects were constipation (in seven patients) and reversible PR-interval prolongation (in two patients). There was no clinical evidence of heart failure in any of the patients. 3. These findings suggest that verapamil has a powerful antianginal action and, in a dose of 360 mg daily, may have a place as a primary agent in the management of chronic stable angina.