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Details of the Trials
Both new studies followed heart attack survivors whose left ventricles were pumping at least 40% of blood with each beat, considered normal contraction. Patients were monitored for approximately three and a half years.
In the BETAMI–DANBLOCK trial conducted in Norway and Denmark with 5,574 participants, beta-blockers provided a clear benefit. Patients taking the medication had a 15% lower risk of death or major cardiovascular events, especially repeat heart attacks, compared to those not on the drugs.
By contrast, the REBOOT trial in Italy and Spain included 8,438 patients and found no benefit. According to the findings, beta-blockers had no impact on death from any cause, repeat heart attacks, or hospitalizations for heart failure.
Possible Reasons for Differences
Dr. Dan Atar of the University of Oslo, who led one of the trials, suggested several factors might explain the differing outcomes. Not all patients received the same type of beta-blocker, and the Scandinavian group tended to be older and more likely to have mild heart dysfunction. In the REBOOT trial, women with strong heart function who received higher doses of beta-blockers actually had worse outcomes than women who were not prescribed the drugs, according to research published in the European Heart Journal.
Despite these results, the REBOOT team did observe benefits among patients with mildly reduced heart function, defined as a left ventricular ejection fraction between 40% and 49%. This subgroup experienced fewer cases of heart attacks, heart failure, or death when treated with beta-blockers. This effect was also confirmed in an analysis pooling data from REBOOT, BETAMI–DANBLOCK, and a Japanese study, published in The Lancet.
What This Means for Patients
According to Dr. Ibanez, “We can now state with confidence that beta-blockers are beneficial” in patients with mildly impaired heart function. However, he also emphasized that “there remains reasonable uncertainty about their benefit” in patients whose hearts function normally. Dr. Atar added that more research is underway, with a specific analysis of patients with normal heart function expected to be presented at a U.S. cardiology meeting in November.
Conclusion
The two new trials highlight both the continued importance and the uncertainty surrounding beta-blocker use after heart attacks. While evidence supports their effectiveness in patients with mildly impaired heart function, questions remain about their value for those with normal heart function. The coming months may bring more clarity, as additional research aims to determine whether this decades-old drug should remain a standard prescription for all patients recovering from a heart attack.
