Selective beta‐1 blockade improves left ventricular energy status, systolic and diastolic function in the rats with postinfarct heart failure

Background: The mechanisms for the beneficial effects of beta-blockade in heart failure are incompletely understood. The aim of this study was to investigate the effects of betal-blockade on cardiac bioenergetics and function in rats during early postinfarct remodeling phase. Methods: Large myocardial infarction (MI) was induced in male Sprague-Dawley rats. Two different groups were studied: rats with MI treated with metoprolol (5 mg!kg/b; n = 9) during 4 weeks and rats with MI placebo treated (n = 9). All rats were investigated with 31P MRS and transthoracic echocardiography (ECHO) 3 days after induction of MI and 4 weeks later. Volume-selective 31P MRS was performed on 2.35 T Bruker Biospec magnet. Results: Trentrnent with metoprolol increased myocardial PCr/ATP ratio indicating improved myocardial energy reserve which was associated with improvement in systolic and diastolic function.