Protective role of chronic beta-blocker intake against the appearance of complex ventricular arrhythmias in acute coronary syndrome

Type of funding sources: None.

Although the presence of ventricular arrhythmias (ventricular tachycardia and ventricular fibrillation) in the context of acute coronary syndromes (ACS) has decreased in the era of early reperfusion, their occurrence may lead to fatal consequences. However, clear predisposing or protective factors have not been identified yet.

Our purpose is to describe the prevalence of ventricular arrhythmias before reperfusion treatment in a population of patients hospitalized due to ACS, as well as the possible protective role of chronic intake of beta-blockers, among other factors.

Retrospective, single-center and observational registry of patients admitted to a Coronary Care Unit from July 2011 to September 2022 with a diagnosis of ACS. The baseline characteristics were described, as well as factors related to diagnosis and treatment. A multivariate analysis was performed to study possible predictors of arrhythmic events.

A total of 3123 patients diagnosed with ACS were included. 682 patients (21.8%) had beta- blockers as a chronic treatment and 201 patients (7.1%) presented ventricular arrhythmias. In Table 1 we can see the baseline characteristics of both groups, as well as the differences between them.

Previous intake of beta-blockers was associated with a lower incidence of ventricular arrhythmias in patients with ST-segment elevation myocardial infarction (STEMI) (11% vs 6%, p 0.002), while no differences were observed between patients without ST-segment elevation myocardial infarction (NSTEMI) (2.3% vs 1.6%, p = 0.435). As shown in the multivariate analysis (Table 2), prior intake of beta-blockers turned out to be a protective factor against the development of ventricular arrhythmias, while ST elevation and worse initial Killip were risk factors.

Chronic intake of beta-blockers could be a protective factor against the development of ventricular arrhythmias before revascularization in patients diagnosed with acute coronary syndrome, specially those with STEMI.