New Research Shows Beta-Blockers Might Not Always Be Helpful After a Heart Attack

Fact checked by Nick Blackmer

• The use of beta-blockers have been a gold standard treatment for heart attack patients for decades
• Beta-blockers work by blocking the effect of adrenaline on the heart muscle, and slow down the heart rate 
• New research suggests that the use of beta-blockers to treat small heart attacks has little benefit

Doctors commonly prescribe beta-blockers to prevent recurrent heart attacks. But new research calls this practice into question, suggesting that the drugs don’t significantly reduce the risk of a second heart attack for people with normal heart function.

The study, published in the New England Journal of Medicine, also revealed little difference in death rates between heart attack survivors without heart failure who did and didn’t take beta-blockers.

Beta-blockers work by inhibiting the release of certain hormones, such as adrenaline, that speed up the heart. While they’re generally considered safe, they can cause side effects such as wheezing, erectile dysfunction, and fatigue.

Doctors typically prescribe beta-blockers for all heart attack patients, but the researchers noted that the protocol stems from studies conducted before the emergence of newer treatments improving heart attack outcomes.

The trial “tells us that beta-blocker therapy shouldn’t be universally prescribed to people who’ve had heart attacks,” Bashar Al-Hemyari, MD, assistant professor in the Division of Cardiovascular Medicine at the University of Texas Medical Branch, who wasn’t involved in the study, told Health. “Instead, it should be reserved individually after weighing the benefits versus risks.”

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Taking Beta-Blockers Didn’t Benefit Heart Attack Patients

The researchers wanted to see whether beta-blockers would benefit people with “small” heart attacks who’d received modern treatment, according to senior author Tomas Jernberg, MD, PhD, professor of cardiology at Karolinska Institutet in Stockholm, Sweden.

To do this, they recruited 5,020 people who’d had an acute heart attack, 95% of whom were being treated at healthcare facilities in Sweden (the rest received treatment in Estonia and New Zealand). All of the patients had a normal ejection fraction, a test that shows how well the heart pumps blood to the body.

Scientists randomly assigned half the participants to take the beta-blockers metoprolol and bisoprolol, while the other half didn’t take the medications. Participants knew if they were taking a beta blocker, and doctors also knew which patients were taking them.

The study occurred between 2017 and 2023, and researchers followed up with participants after an average of 3.5 years. They found that participants who took beta-blockers didn’t fare much better than those who didn’t, with 3.9% of the beta-blocker group dying from any cause vs. 4.1% of the other group. The percentage of these two groups that had another heart attack were 4.5% and 4.7%.

Researchers also found little difference between the two groups in terms of rates of death due to cardiovascular problems, such as myocardial infarction, atrial fibrillation, and heart failure.

Researchers concluded that taking beta-blockers had no significant benefit for these patients.

“Many patients report side effects or suspected side effects with [beta-blockers], so I think this finding will have an impact for thousands of patients,” lead author Troels Yndigegn, MD, an interventional cardiologist at Lund University, said in a statement.

The Study’s Potential Limitations

Jernberg noted that the results apply only to heart attack patients “with preserved heart function” and that researchers “still think beta-blockers are important in patients with larger heart attacks, in which the heart function has been affected.”

He also pointed out that the study wasn’t placebo-controlled, though he doesn’t think this would have introduced bias that could’ve influenced results.

There’s also a question of whether the results would apply outside of Sweden, where most participants received treatment.

While some experts agree that more research is needed to determine the effects of beta-blockers on heart attack patients, they think the study’s results are promising.

“This study is a good example of how a level of knowledge at one stage in our medical, scientific journey may not be relevant or even contrary to what may be beneficial later as we learn more and develop innovative therapies,” Jonathan Fialkow, MD, deputy director of clinical cardiology at Baptist Health Miami Cardiac & Vascular Institute, told Health.

Read the original article on Health.com.