Beta-blockers after Myocardial Infarction: Discontinuation May Be Considered for Patients with Normal Heart Function

Patients who have undergone stent procedures due to myocardial infarction often take beta-blockers for a long period to prevent recurrence. However, questions have consistently been raised about whether even patients whose heart function has recovered to a normal range must take this medication for life. According to a study recently published in the world-renowned medical journal The New England Journal of Medicine, the results showed that patients meeting certain conditions may safely discontinue beta-blocker use.

Targeting Patients with Ejection Fraction of 40% or Higher, Discontinuing Beta-blockers is 'Non-inferior'

According to a video from the medical channel After the Rain, Professor Joo-Yong Hahn of the Department of Cardiology at Samsung Medical Center explained that the important criterion for deciding whether to continue taking beta-blockers after myocardial infarction is 'heart function (ejection fraction)'. Patients whose ejection fraction has dropped to 40% or below or those with heart failure must continue taking the medication because the effects of beta-blockers are very distinct.

On the other hand, the results of a study targeting patients whose heart function is relatively well-preserved, namely those with an ejection fraction of 40% or higher, were different. This study, in which Professor Joo-Yong Hahn participated, was a randomized clinical trial conducted on 2,540 patients across 25 institutions in South Korea. The study results showed that the group that discontinued beta-blockers among the patient group with normal heart function demonstrated 'non-inferiority' (not falling behind existing treatment) in the incidence of major events such as death, recurrence of myocardial infarction, and rehospitalization due to heart failure, compared to the group that continued taking them as before.

As a result of following up for approximately 3.1 years, the incidence of events in the group that stopped the medication was actually slightly lower in numerical terms, but it concluded that the medication could be safely discontinued compared to the existing continuous use group in statistical terms. In particular, it was reported that the discontinuation group showed lower numerical results in the occurrence of stroke as well. These research results are expected to bring significant changes to future treatment guidelines for myocardial infarction patients.

The Role of Beta-blockers and Side Effects to Consider During Long-term Use

Beta-blockers are drugs that regulate the contractility and heart rate of the heart by inhibiting the activation of the sympathetic nervous system. The sympathetic nervous system in our body is divided into alpha and beta systems, and among them, the 'beta1' system is mainly distributed in the heart. When the sympathetic nervous system is activated, the heart beats strongly and fast; when myocardial infarction occurs and part of the heart muscle is damaged, if the heart beats excessively, the oxygen demand increases, which can cause greater damage to the heart. Beta-blockers play a role in making the heart 'calm,' reducing oxygen consumption and protecting the heart.

In the past, because vascular revascularization (such as stent procedures) was not as advanced as it is now, the role of beta-blockers was absolute, but in modern medicine, as stent procedures and various cardioprotective agents have advanced, the dependence on beta-blockers is on a downward trend. Additionally, beta-blockers can cause side effects such as weakness, fatigue, bradycardia (slow pulse), hypotension, and dizziness. In particular, caution is required for patients with COPD or asthma, patients with peripheral vascular disease, and some male patients who may experience sexual dysfunction.

Decisions to Discontinue Medication Must Be Consulted with a Specialist

The results of this study do not provide a 'license to stop medication' for all myocardial infarction patients. Professor Joo-Yong Hahn emphasized that patients with heart failure or patients with decreased heart function were strictly excluded from the study subjects. Since the effects of beta-blockers are proven even in modern treatment environments for patients with decreased heart function, they must maintain their medication.

Therefore, even for patients with normal heart function, medication should not be discontinued arbitrarily. The safest method is to decide whether to discontinue after sufficient consultation with the specialist who prescribed the medication, taking into account the patient's individual condition and comorbidities. The video warns of the danger of patients deciding to stop medication on their own and specifies that they must follow the judgment of medical staff.