For decades, almost every heart-attack survivor has left the hospital with a beta-blocker prescription. The pills slow the heart and lower blood pressure, and they clearly help people whose hearts have been weakened.
A trial published in The New England Journal of Medicine suggests that habit no longer fits a large group of survivors whose hearts still pump normally.
The REBOOT trial followed 8,505 heart-attack survivors at 109 hospitals in Spain and Italy. Every patient had an ejection fraction above 40 percent. None had signs of heart failure.
That number means the heart's main pumping chamber was still pushing out a normal or near-normal share of blood with each beat. The trial ran for a median of almost four years.
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Half of the group was randomly assigned to take a beta-blocker. The other half was not. After follow-up, the two groups looked the same.
The pill did not reduce death from any cause. It did not reduce second heart attacks or hospitalization for heart failure.
What ejection fraction actually means
Ejection fraction is the share of blood the left ventricle squeezes out with each beat. A normal reading sits between roughly 50 and 70 percent.
Modern care protects the pumping chamber so well that about 70 percent of heart-attack survivors now leave the hospital with an ejection fraction above 50.
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The figure comes from the CNIC research center in Madrid that coordinated the trial.
That is a very different population from the one that shaped current prescribing habits. The trials that made beta-blockers standard care were run in the 1980s, before stents, statins and modern clot-busting drugs.
Women fared worse on the pill
A separate analysis of the REBOOT data, published in the European Heart Journal, looked at the results by sex. In women with an ejection fraction of 50 percent or higher, the beta-blocker group fared worse than the control group.
They had higher rates of death, a second heart attack, and heart failure hospitalization.
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The absolute risk of death was about 2.7 percent higher in women who took the drug than in those who did not, over the 3.7 years of follow-up.
The signal was strongest at higher doses. Men in the same trial showed no effect either way.
The authors described the therapy as associated with harm in women, particularly those with preserved ejection fraction on higher doses. No such effect appeared in men.
They stressed that more research is needed to confirm the finding.
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A wider look agrees
A pooled analysis of five major trials, also published in NEJM, combined data on 17,801 heart-attack survivors with an ejection fraction of 50 percent or higher.
Beta-blockers still showed no benefit on death, repeat heart attack, or heart failure.
Patients with mildly reduced pumping sit in a different category. An ejection fraction between 40 and 49 percent means the heart is still weaker than normal.
For that group, a separate meta-analysis in The Lancet found beta-blockers cut the risk of death, heart attack or heart failure hospitalization by 25 percent. So the drugs may still matter in that middle band.
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What to ask your cardiologist
If you take a beta-blocker after a heart attack, do not stop on your own. These drugs are also used for high blood pressure, irregular heartbeats and heart failure.
Stopping abruptly can cause a rebound rise in heart rate and blood pressure.
The practical question to bring to your next appointment is what your most recent ejection fraction is, and whether the beta-blocker is still needed given that number.
This article is made and published by Mie Hermansen, who may have used AI in the preparation.