Electrocardiographic early repolarization is associated with future ventricular arrhythmia after acute myocardial infarction—Systematic Review and Meta-Analysis

Background: Early repolarization (ER) has been linked to ventricular arrhythmia (VA) and sudden cardiac death in patients without structural heart disease. We aimed to assess the latest evidence on whether ER is associated with future VA after acute myocardial infarction (AMI). Methods: We performed a comprehensive search on the topic that assesses ER and VA/adverse cardiovascular events in AMI. We included studies with sufficient details on ER and VA, we also performed a meta-analysis on their morphology. Results: A total of 3350 subjects from 9 studies were included. Five hundred and twenty-one (15.55%) had ER and 2829 (84.45%) did not. On meta-analysis, ER (+) in AMI was associated with VA with a pooled odds ratio (OR) of 3.58 (2.70-4.73), P < 0.001; heterogeneity I² 34%. Subgroup analysis of patients with ST-segment elevation myocardial infarction (STEMI) showed an OR of 2.79 [1.98-3.93], P < 0.001; heterogeneity I² 0%. Inferior location of ER (+) was associated with VA OR 3.98 [1.86-8.53], P = 0.008; I² 67%. Notching had a 5.41 [3.52-8.32], P < 0.001; low heterogeneity I² 0% of having VA. Pooled OR for J-point elevation was 4.72 [2.63-8.46], P < 0.001; I² 25%. Horizontal ST-segment was associated with VA with an OR of 4.30 [1.89-975], P < 0.001; I² 59%. Lateral location and slurred morphology were not associated with VA. Upon sensitivity analysis for inferior location and horizontal ST-segment, removal of a study reduces heterogeneity significantly. Conclusion: Early repolarization especially those with the inferior location, notching morphology, an elevated J-point and horizontal ST-segment had a higher likelihood of VA in AMI including STEMI patients.