Ivabradine vs metoprolol in patients with acute inferior wall myocardial infarction—“Expanding arena for ivabradine”

Abstract

Summary Background Atrioventricular ( AV ) blocks are of concern with the use of beta blockers in inferior wall myocardial infarction ( MI ). Ivabradine lowers heart rate with a lesser risk of AV blocks. Objectives To compare ivabradine with metoprolol in acute inferior wall MI in terms of feasibility, tolerability, and efficacy. Methods It was a prospective double‐blind single‐center randomized controlled study. Of 1032 patients with acute inferior wall MI , 468 eligible patients were randomized in 1:1 manner to ivabradine (group A) and metoprolol (group B). Intention to treat analysis of 426 patients (group A‐232 and group B‐232) was performed. The primary endpoint was 30‐day incidence of major adverse cardiovascular events including death, reinfarction, complete heart block ( CHB ), and heart failure. Secondary endpoints included 30 days incidence of recurrent angina, readmission, first‐ or second‐degree AV block, and tachyarrhythmias. Results Both the drugs decreased the mean heart rate to 62.22±2.95 (group A) vs 62.53±3.59 (group B) beats per minute ( P =0.33). Ejection fraction improved in both the groups (5.15±1.93% in group A vs 5.52±2.18% in group B, P =0.065). The two groups did not differ significantly in their primary endpoints in terms of death (group A=1.72% vs group B=1.72%, OR =1.00, 95% CI =0.25‐4.05, P =1.00), reinfarction (group A=0.86% vs group B=0.86%, OR =1.00, 95% CI =0.14‐7.16, P =1.00), heart failure (group A=4.31% vs group B=2.59%, OR =1.70, 95% CI =0.61‐4.75, P =0.31), or CHB (0% vs 2.59%, OR =0.07, 95% CI =0.00‐1.34, P =0.08). There were no significant differences in the secondary endpoints of recurrent angina, readmission, and tachyarrhythmias except for more first‐ and second‐degree AV blocks with metoprolol (12.93% vs 2.59%, OR =5.59, 95% CI =2.28‐13.72, P =0.0002). Conclusions Ivabradine is well tolerated and equally effective as metoprolol in acute inferior wall ST elevation myocardial infarction patients for lowering the heart rate with lesser risk of AV blocks.