Nitrates and calcium antagonists for silent myocardial ischemia.

Continuous Holter monitoring of patients with coronary heart disease can show transient ischemic episodes occurring spontaneously with or without angina throughout the day. A controlled double-blind trial was conducted comparing the effects of isosorbide-5-mononitrate (IS-5-MN) and nifedipine in patients with documented transient ischemic episodes. Seventy-five percent of the ischemic episodes were not accompanied by pain. Twenty patients with documented coronary heart disease were included; 15 finished the 4-week study (1 patient had headaches, 1 thyrotoxicosis, 1 hypertensive crisis and 2 unstable angina). On a dual-channel FM-recorded electrocardiogram, ischemic episodes were counted when ST deviation was greater than 1 mm for greater than 1 minute. Patients received IS-5-MN (20 mg 3 times a day or 50 mg in a sustained-release tablet) or nifedipine (20 mg in a sustained-release tablet 3 times a day) in random order over four 1-week periods. At the end of each week, Holter monitoring was repeated and showed reductions of episodes by 67% and 67% after weeks of IS-5-MN therapy and 56% and 58% after weeks of nifedipine therapy (all p less than 0.05). Painful and painless episodes were reduced to a similar extent. Individual responses showed great variability, and in all treatment periods not more than half of the patients were completely free of ischemic episodes. One of the 12 patients did not respond to either way of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)