Effects of angiotensin-converting enzyme inhibition on exercise-induced angina and ST segment depression in patients with microvascular angina.

Abstract

OBJECTIVES:

This study was conducted to test the hypothesis that angiotensin-converting enzyme inhibition may lessen myocardial ischemia in patients with microvascular angina.

BACKGROUND:

Patients with syndrome X (angina pectoris, positive findings on exercise testing and normal coronary arteriogram) have a reduced coronary vasodilator reserve ("microvascular angina") and may show an increased sympathetic drive. Angiotensin-converting enzyme inhibition attenuates sympathetic coronary vasoconstriction in patients with coronary artery disease.

METHODS:

Ten patients (seven women and three men, mean age [+/- SD] 53 +/- 6 years) with syndrome X and a reduced coronary flow reserve underwent a randomized, single-blind, crossover, placebo-controlled study of the effects of the angiotensin-converting enzyme inhibitor enalapril on angina and exercise-induced ST segment depression. Assessment was by symptom-limited treadmill exercise testing after 2 weeks of treatment with 10 mg/day of enalapril and after 2 weeks of placebo administration.

RESULTS:

All patients had positive findings on exercise testing (> or = 1 mm ST segment depression and angina) while taking placebo, whereas six patients had a positive test result (four with angina) during enalapril therapy. Total exercise duration and time to 1 mm of ST segment depression were prolonged by enalapril over those obtained with placebo (mean 779 +/- 141 vs. 690 +/- 148 s, p = 0.006 and 690 +/- 204 vs. 485 +/- 241 s, p = 0.007, respectively). The magnitude of ST segment depression was also less with enalapril than with placebo (mean 1.1 +/- 0.4 vs. 1.5 +/- 0.2 mm, p = 0.004). Heart rate and blood pressure at peak exercise and at 1 mm of ST depression were not significantly different during placebo and enalapril treatment.

CONCLUSIONS:

Angiotensin-converting enzyme inhibition lessens exercise-induced ischemia in patients with syndrome X and microvascular angina, probably by a direct modulation of coronary microvascular tone, which results in an increased myocardial oxygen supply.

• Authors: J C Kaski, G Rosano, S Gavrielides, L Chen
• Journal: Journal of the American College of Cardiology (J Am Coll Cardiol) Vol. 23 Issue 3 Pg. 652-7 (Mar 01 1994) ISSN: 0735-1097 [Print] United States
• PMID: 8113548 (Publication Type: Clinical Trial, Comparative Study, Journal Article, Randomized Controlled Trial)

Chemical References

• Enalapril

Topics

• Coronary Circulation (drug effects)
• Electrocardiography (methods)
• Enalapril (therapeutic use)
• Exercise Test
• Exercise Tolerance (physiology)
• Female
• Hemodynamics (drug effects, physiology)
• Humans
• Male
• Microvascular Angina (diagnosis, drug therapy, physiopathology)
• Middle Aged
• Signal Processing, Computer-Assisted
• Single-Blind Method