The clinical significance of early repolarization: A meta-analysis of mortality risk

Background

Early repolarization (ER), historically regarded as benign, have emerged as potential markers for increased risk of cardiovascular (CV) events, including sudden cardiac arrest (SCA) and ventricular fibrillation (VF). This meta-analysis seeks to consolidate evidence from available studies to assess the mortality risks and clinical implications associated with ER.

Objectives

The aim of this meta-analysis is to evaluate the association between ER and various mortality outcomes, including all-cause mortality, CV mortality, and the incidence of VF and SCA in different patient populations.

Methods

A comprehensive literature search was performed across two major medical databases (EMBASE and PubMed) from inception to April 2024. After removing duplicates and screening, 36 studies were included in the final analysis. The studies included diverse populations, such as the general public, ICD patients, myocardial infarction (MI)/acute coronary syndrome (ACS) patients, and survivors of SCA. Odds Ratios (ORs) were calculated using a random-effects model to account for heterogeneity among studies. The I² statistic was employed to quantify heterogeneity, and publication bias was assessed using the Eggers regression and funnel plots.

Results

Out of 744 initially identified articles, 36 studies met the inclusion criteria for the meta-analysis, including general populations, ICD patients, MI/ ACS patients, and survivors of SCA. The analysis revealed that the presence of ER was not significantly associated with all-cause mortality (OR = 1.2, 95% CI 0.92–1.59, p = 0.18, I² = 96%) or CV mortality (OR = 1.3, 95% CI: 0.87–1.9, P = 0.19, I² = 94%) in the general population. However, ER was significantly associated with an increased risk of VF and SCA (OR = 3.57, 95% CI 1.2–10.7, p = 0.02, I² = 90%), and particularly with VF in ICD, SCA survivors and MI/ACS patients (OR = 4.01, 95% CI 2.5–6.4, p < 0.001, I² = 76%). These findings underscore the need to consider ER patterns in risk assessments, especially for patients with a history of MI or those at high risk for ventricular arrhythmias.

Conclusions

This meta-analysis confirms that while ER patterns do not significantly impact all-cause or CV mortality, they are strongly associated with an increased risk of VF and SCA, particularly in patients with a history of MI or ACS. These findings highlight the importance of considering ER patterns in clinical risk assessments, especially in high-risk populations.