A decades-old pill remains helpful for heart attack patients even with modern treatments that can prevent lasting damage to heart muscle, two large trials have shown.

Still unclear is whether all patients, or only some, benefit from so-called beta-blocker drugs, which are typically prescribed to everyone after a heart attack.

Two sharply contradictory reports were presented on Saturday at a large cardiology meeting in Madrid and published in The New England Journal of Medicine.

It is not unusual for trials to yield different results, said Dr Borja Ibanez of Centro Nac­­io­nal de Investigaciones Cardiov­a­sc­ul­ares Carlos III in Madrid, who led one of the trials.

Somewhat uncommon is to see two trials with apparently divergent findings presented on the same day.

Most important, Ibanez said, is the finding both teams agree on, which is that beta-blockers reduce the combined risk of another heart attack, heart failure, or death in patients without heart failure but with mildly impaired heart function.

The question is whether the pills are beneficial or useless for those with normally functioning hearts, who account for about 80pc of patients after a first heart attack.

Beta-blocker manufacturers include My­­lan, Novartis, Pfizer, Abbott, Teva Pharmac­e­utical Industries, Amneal Pharmac­eu­tic­als, Sun Pharmaceutical Industries, Lupin, ANI Pharmaceuticals, and Eagle Pharmace­u­ticals. The drugs work by inhibiting the hormones epinephrine and norepinephrine, thereby lowering heart rate and blood pressure, decreasing the workload on the heart and reducing its oxygen demand.

Both new trials involved heart attack survivors whose hearts were still contracting normally, that is, the left ventricle was pumping out at least 40pc of its blood with each beat. Both trials followed patients for roughly 3.5 years.

Among 5,574 volunteers in the BETAM­I­D­­AN­­BLOCK study from Norway and Denm­ark, the drugs showed a clear benefit. Patie­n­ts randomly assigned to receive beta-blockers had a 15pc lower risk of death or major adverse cardiovascular event, partic­ularly a repeat heart attack, compared to patients not taking these pills, investigators found.

But among the 8,438 participants in the REBOOT trial conducted in Italy and Spain, beta-blockers had no effect on the incidence of death from any cause, a repeat heart attack, or hospitalisation for heart failure, according to a separate report.

Some of the difference may be due to the fact that patients didn’t all receive the same beta-blockers, and the Scandinavian pat­i­e­nts might have been more prone to adverse events because they were slightly older than patients in Spain and Italy and more of them had mild heart dysfunction, said Dr Dan Atar of the University of Oslo, who led one of the trials.

Among female participants in REBOOT, those taking beta-blockers — particularly those with good heart function receiving higher doses had more adverse outcomes than women not taking the drugs, researchers reported in the European Heart Journal.

In REBOOT, researchers did see a lower rate of new heart attacks, heart failure, or death with beta-blocker use by patients with mildly reduced heart function, as indicated by a left ventricular ejection fraction between 40pc and 49pc.

Published in Dawn, August 31st, 2025