New Findings: Beta Blockers May Not Benefit Heart Attack Patients, Worse Outcomes Seen in Women

Beta blockers—commonly prescribed drugs for heart conditions including myocardial infarctions—may not provide any clinical benefits to patients who have had uncomplicated heart attacks with preserved cardiac function. Despite being the standard treatment for over four decades.

The "REBOOT Trial," led by senior investigator Valentin Fuster, MD, PhD, President of Mount Sinai Fuster Heart Hospital and General Director of Spain's CNIC (Centro Nacional de Investigaciones Cardiovasculares), has produced these groundbreaking findings.

Results were revealed on August 30th during a "Hot Line" session at the European Society of Cardiology Congress in Madrid and simultaneously published in The New England Journal of Medicine.

A REBOOT substudy, published in the European Heart Journal, reveals that women treated with beta blockers were at a higher risk of death, heart attack, or hospitalization for heart failure compared to those not taking the drug. This increased risk was not observed in men.

"This trial will transform international clinical guidelines," says Dr. Fuster. "Alongside other landmark trials such as SECURE with the polypill and DapaTAVI, which have already altered global approaches to cardiovascular disease."

The SECURE trial demonstrated that a single pill combining aspirin, ramipril, and atorvastatin reduced cardiovascular events by 33% post-heart attack. The DapaTAVI study revealed improved prognosis for aortic stenosis patients treated with dapagliflozin or empagliflozin alongside transcatheter aortic valve implantation.

"The REBOOT findings are set to change clinical practice worldwide," states Principal Investigator Borja Ibáñez, MD, CNIC's Scientific Director. Currently, over 80% of patients with uncomplicated myocardial infarctions are discharged on beta blockers - a practice that the REBOOT results challenge.

Although believed to be safe, beta blockers can cause side effects like fatigue, low heart rate, and sexual dysfunction. Prescribed post-heart attack for over forty years, their efficacy had not been rigorously proven until now by the largest clinical trial on the subject, coordinated by CNIC in collaboration with Italy's Mario Negri Institute.

Researchers involved 8,505 patients from 109 hospitals across Spain and Italy. Patients were randomly assigned to receive or not receive beta blockers after discharge. Over a median follow-up period of nearly four years, no significant differences emerged between the groups regarding death rate, heart attack recurrence, or hospitalization for heart failure.

Further subgroup analysis in REBOOT found that women receiving beta blockers experienced more adverse events. The risk was 2.7% higher for mortality compared to non-treated counterparts over 3.7 years of follow-up. This elevated risk applied only to women with fully normal cardiac function post-heart attack (left ventricular ejection fraction ≥50%).

"Post-heart attack, patients receive multiple medications, complicating treatment adherence," explains Dr. Ibáñez. "Originally, beta blockers were added to standard therapy because they significantly reduced mortality by lowering cardiac oxygen demand and preventing arrhythmias.

However, therapies have evolved. Today, occluded coronary arteries are rapidly reopened, drastically reducing the risk of serious complications like arrhythmias. In this context - where heart damage is diminished - the need for beta blockers becomes questionable."

"The trial targeted treatment optimization based on solid scientific evidence and without commercial interests," Dr. Ibáñez added.