Betablockers After Heart Attack: New Study Questions Routine Use

For over four decades, beta-blockers have been a standard prescription following a myocardial infarction, commonly known as a heart attack. However, a comprehensive analysis of the REBOOT clinical trial, conducted by researchers at the National Center for Cardiovascular Research (CNIC), challenges this long-held practice. The study reveals that beta-blockers offer no significant clinical benefit, either in the immediate aftermath of a heart attack or during the longer-term recovery phase, for patients with normal heart function.

Challenging a Long-Standing Belief

Dr. Valentín Fuster, Director General of CNIC and a co-investigator in the study, stated that the findings, combined with evidence from REBOOT and related trials, “question a dogma rooted for a long time.” He emphasized that simplifying treatment when benefits aren’t demonstrated is just as crucial as introducing new therapies.

Historically, beta-blockers were considered essential after a heart attack due to their ability to lower heart rate, reduce the heart’s oxygen demand, and prevent irregular heartbeats. However, the evidence supporting this practice stemmed from trials conducted before the widespread adoption of modern treatments like coronary reperfusion, advanced antithrombotic therapy, and high-intensity statins.

The REBOOT Trial: A Modern Assessment

To address the gap in evidence with contemporary treatments, the REBOOT trial enrolled 8,438 patients who had experienced a heart attack and maintained a left ventricular ejection fraction (LVEF) above 40% – meaning their heart function was not significantly impaired. These patients, all receiving standard current care, were followed for nearly four years. Researchers compared outcomes between those prescribed beta-blockers and those who did not receive this additional medication.

No Detectable Clinical Benefit

The pre-specified analysis of the REBOOT trial, the largest randomized trial ever conducted on beta-blocker use after a heart attack, demonstrated that treatment with beta-blockers was not linked to a reduction in mortality, the risk of another heart attack, or hospitalizations for heart failure. This held true both during the initial phase following the heart attack (acute coronary syndrome) and throughout the subsequent follow-up period (chronic coronary syndrome).

Of the 623 events comprising the primary outcome – encompassing death from any cause, non-fatal reinfarction, or heart failure hospitalization – no statistically significant differences were observed between patients who received beta-blockers and those who did not. This reinforces the conclusion that routine use of these drugs in patients with preserved heart function does not improve overall clinical outcomes.

Further analysis even suggests that higher doses of beta-blockers during the chronic phase might be associated with worse results, highlighting the need for individualized treatment plans and a reassessment of long-term prescriptions in these patients.

Dr. Borja Ibáñez, CNIC’s Scientific Director, cardiologist at Hospital Universitario Fundación Jiménez Díaz, and principal investigator of the study, stated that the findings provide “definitive proof” that beta-blockers do not improve outcomes in patients with preserved left ventricular ejection fraction, regardless of whether they are in the acute or chronic phase after a heart attack. He added that this has “enormous clinical relevance” given that millions worldwide continue to take beta-blockers for years post-infarction without clear evidence of benefit.

Dr. Xavier Rosselló, the study’s first author and a researcher at CNIC and Hospital Universitari Son Espases, explained that by separating the acute and chronic phases, researchers could rigorously determine if the timing of administration mattered. The answer, he stated, is clear: beta-blockers do not offer protection in either context for patients with preserved ejection fraction.

In Spain alone, it is estimated that over 1.2 million people take beta-blockers daily, many following a heart attack without complications to heart function. This indicates that millions of prescriptions are maintained out of clinical habit, despite the lack of solid evidence of benefit in this population.

What’s Next?

Clinical guidelines are likely to be revised in light of this new evidence. Cardiologists and general practitioners may need to individually assess their post-infarction patients to determine whether to continue or discontinue beta-blocker therapy, always under medical supervision and with shared decision-making with the patient. A possible next step could involve developing more refined risk stratification tools to identify patients who might still benefit from beta-blockers based on individual characteristics.

Frequently Asked Questions

What did the REBOOT trial specifically investigate?

The REBOOT trial investigated whether beta-blockers provided a clinical benefit to patients who had experienced a heart attack but maintained normal heart function (left ventricular ejection fraction above 40%).

What were the key findings of the study?

The study found that beta-blockers were not associated with a reduction in mortality, risk of another heart attack, or hospitalizations for heart failure, in patients with preserved heart function, either in the immediate aftermath of a heart attack or during long-term recovery.

Will this change how heart attack patients are treated?

Clinical guidelines are expected to be reviewed, and doctors may begin to individually assess whether patients should continue taking beta-blockers after a heart attack, particularly those with normal heart function.

As medical understanding evolves, how might this new research influence your conversations with your healthcare provider about your heart health?