Effects of metoprolol on effort angina during the postprandial state

To determine whether beta blockers prevent the more rapid onset of effort angina during the postprandial state, metoprolol 100 mg was given before and after an 800-calorie meal in 12 male patients with stable angina and coronary artery disease. Three graded treadmill exercise tests were done daily on 2 days. After an overnight fast the first test on each day was done after a placebo to detect day-to-day variations. The second test was done 90 min after metoprolol or placebo given orally in a double-blind randomized fashion. Immediately thereafter the patients ate their meal and did their third test 30 min later. There was no significant difference between the first test on each day. After placebo the postprandial state was associated with an earlier onset of effort angina (310 and 370 sec, p less than 0.01) and with greater heart rate and systolic blood pressure rises for any work load. After metoprolol, however, there was no significant difference between the pre- and postprandial findings. During the postprandial state metoprolol delayed the onset of angina more than placebo (385 and 310 sec) and positive electrocardiogram (310 and 228 sec) and induced lowering of maximal heart rate (120 and 144 bpm) and systolic blood pressure (157 and 187 mm Hg) (p less than 0.01). Metoprolol slowed the rapid onset of effort agina during the postprandial state.