What is the role of beta blockers in the treatment of dilated cardiomyopathy?

Updated: Nov 28, 2018
  • Author: Vinh Q Nguyen, MD, FACC; Chief Editor: Gyanendra K Sharma, MD, FACC, FASE  more...
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Answer

Previously believed to be contraindicated in patients with left ventricular dysfunction, this class of medications has moved to the forefront of heart failure treatment. Several trials have shown that beta-blockers are both safe and effective in the treatment persons with any class of heart failure and that adding beta-blockers to outpatient management of chronic heart failure (CHF) yields great reductions in mortality rates.

Carvedilol, bisoprolol, and metoprolol CR/XL are the only agents currently approved by the US Food and Drug Administration (FDA) for use in patients with heart failure. Head-to-head studies (Carvedilol or Metoprolol European Trial [COMET], carvedilol vs metoprolol) indicated that carvedilol (a beta-1, alpha, and beta-2 receptor blocker), improved survival and cardiovascular hospitalizations more than the beta-1 selective beta-blocker metoprolol tartrate. [96]

The SENIORS trial (Study of Effects of Nebivolol Intervention on Outcomes and Rehospitalization in Seniors With Heart Failure) showed that patients older than 70 years regardless of LVEF, nebivolol, a beta blocker with vasodilating properties, reduced the primary outcome of all-cause mortality or hospitalization for cardiovascular events. [97] However, the seconday outcome of all-cause mortality was not significant reduced.

The 1993 Metoprolol in Dilated Cardiomyopathy (MDC) study reported a 34% reduction in primary endpoints (ie, need for heart transplant, death) in heart failure patients who were treated with metoprolol in addition to conventional therapies. [98] In 1996, the US Carvedilol Study showed a 65% reduction in mortality in patients with predominantly mild symptoms of heart failure (New York Heart Association [NYHA] class II) treated with carvedilol. [99]

The international Metoprolol CR/XL Randomized Intervention Trial in CHF (MERIT-HF), the largest trial ever completed using a beta-blocker in heart failure, closed prematurely following an interim analysis that identified a highly positive effect of metoprolol-XL on all causes of mortality. [100] MERIT-HF was a randomized, double-blind trial that compared the effects of extended-release metoprolol (metoprolol-XL) with the effects of a placebo on survival and other outcome measures (eg, sudden death, hospitalization for heart failure, quality of life) in patients with mostly mild symptoms (NYHA class II).

A statistically significant 34% reduction in relative risk for total mortality at 1 year was observed; mortality rates were 7.2% in the metoprolol-XL group and 11% in the placebo group. Results at the time of study termination also revealed a 38% reduction in cardiovascular mortality, a 41% reduction in sudden death, and a 49% reduction in CHF mortality. [100, 101]

Beta-blocker trials include the following (all trials used beta-blockers in addition to standard therapy for heart failure):

  • US Carvedilol Heart Failure Study Group from 1996

  • Cardiac Insufficiency Bisoprolol Study II (CIBIS II) from 1999 (bisoprolol vs placebo), NYHA class III-IV: Showed reduced mortality and hospitalization rates [102]

  • Carvedilol Prospective Randomized Cumulative Survival (COPERNICUS) from 2000 (carvedilol vs placebo): Demonstrated reduction in mortality by 35% in a population of patients with severe symptoms of heart failure (NYHA class IV) [103]


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