Additive beneficial effects of beta blockers in the prevention of symptomatic heart failure

The prevention of symptomatic heart failure represents the treatment of patients in the A and B stages of AHA/ACC heart failure classification. Stage A refers to patients without structural heart disease but at risk to develop chronic heart failure. The major risk factors in stage A are hypertension, diabetes, atherosclerosis, family history of coronary artery disease and history of cardiotoxic drug use. In this stage, blockers hypertension is the primary area in which beta blockers may be useful. Beta blockers seem not to be superior to other medication in reducing the development of heart failure due to hypertension. Stage B heart failure refers to structural heart disease but without symptoms of heart failure. This includes patients with asymptomatic valvular disease, asymptomatic left ventricular (LV) dysfunction, previous myocardial infarction with or without LV dysfunction. In asymptomatic valvular disease no data are available on the efficacy of beta blockers to prevent heart failure. In asymptomatic LV dysfunction only few asymptomatic patients have been enrolled in the trials which tested beta blockers. NYHA I patients were barely 228 in the MDC, MERIT and ANZ trials altogether. The REVERT trial was the only trial focusing on NYHA I patients with LV ejection fraction less than 40%. Metoprolol extended release on top of ACE inhibitors ameliorated LV systolic volume and ejection fraction. A post hoc analysis of the SOLVD Prevention trial demonstrated that beta blockers reduced death and development of heart failure. Similar results were reported in post MI patients in a post hoc analysis of the SAVE trial (Asymptomatic LV failure post myocardial infarction). In the CAPRICORN trial about 65% of the patients were not taking diuretics and then could be considered asymptomatic. The study revealed a reduction in mortality and a non-significant trend toward reduction of death and hospital admission for heart failure. Conclusions: beta blockers are not specifically indicated in stage A heart failure. On the contrary, in most of the stage B patients, and particularly after MI, beta blockers are indicated to reduce mortality and, probably, also the progression toward symptomatic heart failure.