Effects of amlodipine on transient myocardial ischaemia in patients with a severe coronary condition treated with a beta-blocker. Amlor-Holter Study Investigators.

Abstract

The purpose of this trial was to study the additional anti-ischaemic effects of amlodipine in coronary patients with ambulant ischaemia despite beta-blocker therapy. Beta-blockers are the most effective drug therapy for reducing the frequency and duration of ambulatory ischaemic episodes. However, the therapeutic advantage of combined calcium antagonist-beta-blocker treatment remains questionable. Three hundred and thirteen patients with documented coronary artery disease, a positive exercise test within 6 months before entry and background beta-blocker therapy, were screened. Inclusion criteria (> or = 4 episodes of transient ST segment depression of > or = 1.0 mm and/or > or = 20 min of ischaemia) were demonstrated in a 48 h ECG during the placebo run-in period in 84 (25%) of the patients. Eighty-nine percent of the ischaemic episodes were silent. The eligible patients were then randomized in a 2-week, double-blind, parallel group study comparing placebo to amlodipine 10 mg daily added to the beta-blocker. The anti-ischaemic efficacy of the combination therapy was assessed by 48 h ECG monitoring and exercise tests. Compared to placebo, amlodipine did not significantly reduce either the frequency (3.7 +/- 4.3 vs 4 +/- 4.8 episodes in the amlodipine group) or the duration of ambulatory ischaemia (mean duration: 43.9 +/- 57.1 vs 39.6 +/- 65.7 min, total duration 3.1 +/- 6.7 vs 2.8 +/- 6.1 h). Exercise-induced ST segment depression tended to decrease with amlodipine (58% vs 73% in the placebo group) and the ischaemia-free workload capacity was increased (+1.7 stage vs 0.7 stage in the placebo group, P = 0.08). These results suggest that 2 weeks treatment with amlodipine may not provide any additional anti-ischaemic benefit in patients with ambulant ischaemia resistant to a beta-blocker therapy.