Beta blockers—drugs commonly prescribed for a range of cardiac conditions, including heart attacks—provide no clinical benefit for patients who have had an uncomplicated myocardial infarction with preserved heart function. Beta blockers have been the standard treatment for these patients for 40 years.
This is a breakthrough discovery from the "REBOOT Trial" with senior investigator Valentin Fuster, MD, PhD, President of Mount Sinai Fuster Heart Hospital and General Director of Spain's Centro Nacional de Investigaciones Cardiovasculares (CNIC). The study results, which could overturn a standard treatment paradigm, were presented on Saturday, August 30, during a "Hot Line" session at the European Society of Cardiology Congress in Madrid, and simultaneously published in The New England Journal of Medicine.
Additionally, a REBOOT substudy, published Saturday, August 30, in the European Heart Journal, shows that women treated with beta blockers had a higher risk of death, heart attack, or hospitalization for heart failure compared to women not receiving the drug. Men did not have this increased risk.
"This trial will reshape all international clinical guidelines. It joins other previous landmark trials led by CNIC and Mount Sinai—such as SECURE with the polypill and DapaTAVI, with SLT2 inhibition associated to TAVI—that have already transformed some global approaches to cardiovascular disease," says Dr. Fuster.
The SECURE trial showed a polypill, a single pill that that combines three medications - which contains aspirin, ramipril, and atorvastatin – reduces cardiovascular events by 33 percent in patients treated with this after a heart attack. The DapaTAVI trial showed both dapagliflozin and the related medication empagliflozin - drugs used to treat diabetes- improves the prognosis of patients with aortic stenosis treated by transcatheter aortic valve implantation.
"REBOOT will change clinical practice worldwide," says Principal Investigator Borja Ibáñez, MD, CNIC's Scientific Director, who presented the results. "Currently, more than 80 percent of patients with uncomplicated myocardial infarction are discharged on beta blockers. The REBOOT findings represent one of the most significant advances in heart attack treatment in decades."
Although generally considered safe, beta blockers can cause side effects such as fatigue, bradycardia (low heart rate), and sexual dysfunction. For more than 40 years, beta blockers have been prescribed as a standard treatment after a heart attack, but their benefit in the context of modern treatments was unproven. The REBOOT trial, is the largest clinical trial on this subject. The international study was coordinated by CNIC in collaboration with the Mario Negri Institute for Pharmacological Research in Milan.
Researchers enrolled 8,505 patients across 109 hospitals in Spain and Italy. Participants were randomly assigned to receive or not receive beta blockers after hospital discharge. All patients otherwise received the current standard of care and were followed for a median of nearly four years. The results showed no significant differences between the two groups in rates of death, recurrent heart attack, or hospitalization for heart failure.
A REBOOT subgroup analysis found that women treated with beta blockers experienced more adverse events. Results show women treated with beta-blockers had a 2.7 percent higher absolute risk of mortality compared to those not treated with beta-blockers during the 3.7 years of follow-up of the study. The elevated risk when treated with beta-blockers was restricted to women with a complete normal cardiac function after a heart attack (left ventricular ejection fraction of 50 percent or higher). Those with a mild deterioration in cardiac function did not have an excess risk of adverse outcomes when treated with beta-blockers.
"After a heart attack, patients are typically prescribed multiple medications, which can make adherence difficult," explains Dr. Ibáñez. "Beta blockers were added to standard treatment early on because they significantly reduced mortality at the time. Their benefits were linked to reduced cardiac oxygen demand and arrhythmia prevention. But therapies have evolved. Today, occluded coronary arteries are reopened rapidly and systematically, drastically lowering the risk of serious complications such as arrhythmias. In this new context—where the extent of heart damage is smaller—the need for beta blockers is unclear. While we often test new drugs, it's much less common to rigorously question the continued need for older treatments."
That was the motivation behind REBOOT.
"The trial was designed to optimize heart attack care based on solid scientific evidence and without commercial interests. These results will help streamline treatment, reduce side effects, and improve quality of life for thousands of patients every year," Dr. Ibanez adds.
REBOOT was conducted without pharmaceutical industry funding.
Mount Sinai Is a World Leader in Cardiology and Heart Surgery
Mount Sinai Fuster Heart Hospital at The Mount Sinai Hospital ranks No. 2 nationally for cardiology, heart, and vascular surgery, according to U.S. News & World Report®. It also ranks No. 1 in New York and No. 6 globally according to Newsweek's "The World's Best Specialized Hospitals."
It is part of Mount Sinai Health System, which is New York City's largest academic medical system, encompassing seven hospitals, a leading medical school, and a vast network of ambulatory practices throughout the greater New York region. We advance medicine and health through unrivaled education and translational research and discovery to deliver care that is the safest, highest-quality, most accessible and equitable, and the best value of any health system in the nation. The Health System includes approximately 9,000 primary and specialty care physicians; 10 free-standing joint-venture centers throughout the five boroughs of New York City, Westchester, Long Island, and Florida; and 48 multidisciplinary research, educational, and clinical institutes. Hospitals within the Health System are consistently ranked by Newsweek's® "The World's Best Smart Hospitals" and by U.S. News & World Report's® "Best Hospitals" and "Best Children's Hospitals." The Mount Sinai Hospital is on the U.S. News & World Report's® "Best Hospitals" Honor Roll for 2025-2026.
