β-Blocker in Post-Myocardial Infarct Survivors with Preserved Left Ventricular Systolic Function

BACKGROUND: Long-term beta-blockade therapy is beneficial in post-myocardial infarct (MI) patients with left ventricular (LV) dysfunction; nevertheless, its benefit in post-MI patients with preserved LV function remains unclear. The objective of this study is to investigate the effects of long-term beta-blockade therapy on the clinical outcomes in post-MI patients with preserved LV function. HYPOTHESIS: The beneficial effects of long-term beta-blockade therapy in post-MI patients with impaired LV function may extend to those with preserved LV function. METHODS: Of 617 consecutive post-MI patients referred for cardiac rehabilitation program, 208 patients (age: 62.7 +/- 0.8 years; male: 76%) with preserved LV function (ejection fraction >or= 50%), negative exercise stress test, and on angiotensin-converting enzyme inhibition were studied. RESULTS: Baseline characteristics were comparable between patients on beta-blocker (n = 154) and not on beta-blocker (n = 54). After a mean follow-up of 58.5 +/- 2.7 months, 14 patients not on beta-blocker (26%) and 14 patients on beta-blocker (9%) died with hazard ratio (HR) of 2.5 (95% confidence interval CI: 1.25-6.42, P = 0.01). Likewise, patients not on beta-blocker had a higher incidence of cardiac death (HR: 3.0, 95% CI: 1.07-12.10, P = 0.04), and non-sudden cardiac death (HR: 10.1, 95% CI: 1.82-89.65, P = 0.01), but not sudden cardiac death compared with patients on beta-blocker (HR: 1.6, 95% CI: 0.34-7.61, P = 0.54). A Cox regression analysis revealed that only advanced age (>or=75 years; HR: 2.55, 95% CI: 1.18-5.49, P = 0.02) and the absence of beta-blocker (HR: 2.41, 95% CI: 1.14-5.09, P = 0.02) were independent predictors for mortality. CONCLUSION: beta-blocker use was associated with a decrease in overall mortality and cardiac death in post-MI patients with preserved LV function.