Long-term beta-blockers after heart attack offer no cardiovascular benefits
Beta-blockers are prescribed as a matter of course to people following a heart attack, but a new study, the largest of its kind, has found that for people who have not experienced cardiac complications, taking beta-blockers for more than a year after a heart attack does not improve cardiovascular outcomes. The results may lead to a reassessment of the use of this commonly prescribed class of drugs.
Beta-blockers – which have been around for more than 50 years – stop the release of the stress hormone epinephrine (adrenaline), causing the heart to beat more slowly and with less force and lowering blood pressure.
In 2022, approximately 30 million Americans were taking beta-blockers. They’re regularly prescribed after a heart attack (myocardial infarction) to reduce the risk of further heart attacks, but they have downsides. Common side effects of beta-blockers include feeling lightheaded, cold fingers and toes, fatigue, and weight gain. Less commonly, they can cause depression and difficulty sleeping.
A recent study investigated 43,618 adult patients who’d had a heart attack but did not have subsequent heart failure or other cardiac complications to see whether taking beta-blockers in the long term provided any benefit. It’s the largest study to do so.
Many studies into the use of beta-blockers following a heart attack date back 25 years or more, so the researchers wanted to look at whether their use should be reconsidered in light of how medical treatments have changed. For example, it’s now common to use drugs that prevent clots from forming and growing in the heart’s blood vessels as a first-line treatment.
“Recommendations on the duration of beta-blocker therapy are variable or absent because this question was not specifically evaluated in clinical trials,” said Tom Evans and Ralph Stewart from Te Whatu Ora Health in Auckland, New Zealand, in an opinion piece about the study. “Most patients take daily medications for many years after a myocardial infarction because they believe they are beneficial.”
The researchers obtained data from the Swedish Web-system for Enhancement and Development of Evidence-based Care in Heart Disease Evaluated According to Recommended Therapies (SWEDEHEART), Sweden’s national register for coronary heart disease.
The study’s participants had had a heart attack requiring hospital treatment between 2005 and 2016 but none of them had heart failure or left ventricular systolic dysfunction (LVSD), a serious complication of heart attack that causes the heart's left lower chamber (ventricle) to pump less effectively a year after the heart attack.
Comparing those who’d been treated with beta-blockers to those who hadn’t, the researchers found that after an average monitoring period of four-and-a-half years, treatment with beta-blockers beyond one year wasn’t associated with improved cardiovascular outcomes.
The researchers say that the study’s findings should lead to rethinking the use of beta-blockers to treat patients with no complications following a heart attack, particularly given the risk of side effects such as fatigue and depression. For them, it becomes a question of quality of life.
They recommend further research to confirm the relationship between beta-blocker use and cardiac outcomes in these patients.
The study was published in the journal Heart.