Silent ischemic interval on exercise test is a predictor of response to drug therapy: A randomized crossover trial of metoprolol versus diltiazem in stable angina

Background and hypothesis: There is no method available to predict the relative antianginal efficacy of beta blockers and calcium‐channel antagonists. The present study was undertaken to assess the role of silent ischemic interval (SII) on exercise treadmill test (ETT) as a predictor of response to therapy with metoprolol and diltiazem in patients with stable angina. Methods: Thirty‐four patients with stable angina were divided into two groups depending upon the presence or absence of an SII gap of at least 1 min between onset of ST depression and appearance of angina on ETT. Metoprolol (50–100 mg twice daily) and diltiazem (60–120 mg three times daily) were randomly assigned for 6 weeks to patients in each group, and then patients were crossed over for further 6 weeks after a washout period of 2 weeks. Antianginal efficacy was assessed by clinical and exercise parameters. Results: In patients with SII, the clinical responder rate was better with metoprolol than with diltiazem (90 vs. 60%, respectively), and on ETT, metoprolol produced significant improvement in the total exercise time (p