Taking beta blockers after a heart attack did not significantly reduce the risk of death or a second heart attack in people with normal heart pumping capacity, as indicated by an ejection fraction of 50% or greater , according to a study presented at the American College of Cardiology Annual Scientific Session.
The findings call into question the routine use of beta blockers for all heart attack patients, which have been the mainstay of care for decades. About 50% of heart attack survivors do not suffer from heart failure. Among these patients, the study found no difference in the primary composite endpoint of death from any cause or new nonfatal heart attack between those who were prescribed beta blockers and those who were not. had not prescribed any.
I think that following this study, many doctors will not find an indication to systematically treat all their patients with beta-blockers following a heart attack. We believe the evidence still supports beta blockers for patients with significant myocardial infarction and heart failure, but for patients with no signs of heart failure and a normal ejection fraction, this trial establishes that there is no indication that routine use of beta-blockers is beneficial.”
Troels Yndigegn, MD, interventional cardiologist at Lund University in Sweden and lead author of the study
Heart failure occurs when the heart muscle becomes too weak or too stiff to pump blood effectively. It is primarily assessed in terms of left ventricular ejection fraction, which is the proportion of blood expelled from the left ventricle of the heart with each heartbeat. An ejection fraction above 40 – 50% is considered normal.
Beta blockers lower blood pressure by inhibiting certain hormones, such as adrenaline, that make the heart race. Many clinicians prescribe beta blockers to all patients after a heart attack, usually for at least a year or often for the rest of the patient’s life, based on evidence showing that they can help prevent a second attack. cardiac. However, researchers said the clinical trials that led to this routine use of beta blockers were conducted before the advent of many newer procedures that are now widely used to open blocked arteries.
“At that time, the damage to the heart muscle was greater than today and we did not have the ability to revascularize patients with percutaneous coronary intervention and stents as we do today,” said Yndigegn. “What we’re seeing today is more myocardial infarctions, which are smaller in magnitude and don’t damage the heart muscle to the same extent.”
To elucidate the potential benefits of beta blockers given this new landscape, the REDUCE-AMI study enrolled 5,020 patients treated for acute heart attack at 45 centers in Sweden, Estonia, and New Zealand who participated in the SWEDEHEART registry . All patients had an ejection fraction of 50% or more, assessed by an echocardiogram performed within a week of their heart attack. Half were randomly assigned to receive long-term beta-blocker medications and the rest did not take beta-blockers.
Over a median follow-up period of 3.5 years, there was no significant difference between groups in the rate of the primary composite endpoint or in secondary clinical endpoints such as heart failure, atrial fibrillation, or symptoms. such as chest pain and shortness of breath. There were also no differences in safety parameters such as stroke, abnormally low blood pressure or fainting.
Researchers said the lack of benefit associated with beta blockers seen in this patient group could potentially free many patients from the burden of taking these medications, allowing them to avoid side effects such as impaired speech. mood, fatigue and sexual dysfunction.
“Many patients report side effects or suspect side effects with these medications, so I think this finding will impact thousands of patients,” Yndigegn said.
The study did not involve a placebo control and participants knew which group they were assigned to. Although this open approach could potentially introduce bias, the researchers said it would likely not have an effect on outcomes such as deaths and heart attacks. Yndigegn said the findings should be generalizable beyond the population in which the study was conducted and added that other observational studies are underway and may help shed light on the routine use of beta- blockers in various populations.
The researchers plan to analyze outcomes related to quality of life and sexual health separately.
The study was funded by the Swedish Research Council, the Swedish Heart and Lung Foundation and Stockholm County Council.
This study was simultaneously published online in the New England Journal of Medicine at the time of presentation.
Yndigegn will be available to the media at a press conference on Sunday, April 7, 2024 at 11:15 a.m. ET / 3:15 p.m. UTC in Room B203.
Yndigegn will present the study, “Long-Term Beta-Blocker Treatment After Acute Myocardial Infarction and Preserved Left Ventricular Ejection Fraction – The REDUCE-AMI Trial,” on Sunday, April 7, 2024, at 9:45 a.m. ET/1 p.m. 45 a.m. UTC in the main tent of Hall B-1.
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