Early Repolarization Pattern Is Associated with Increased Risk of Early Ventricular Arrhythmias during Acute ST Segment Elevation Myocardial Infarction.

BACKGROUND: Early repolarization (ER) and acute ST segment elevation myocardial infarction (STEMI) are sharing the pathophysiology of J wave syndromes. It is speculated that early ventricular arrhythmias (VAs) during STEMI may be predisposed by ER. Our aim was to study the association between ER pattern and risk of VAs during acute STEMI.

METHODS: The study included 102 male patients with acute STEMI who were divided into two groups: cases and controls. Cases included 52 patients with sustained VAs during the first 48 hours from the onset of STEMI, while controls included 50 patients with no VAs. On 12-lead surface electrocardiogram, ER was defined as ≥ 1 mm elevation of J point in at least two inferior or lateral leads with or without ST segment elevation.

RESULTS: Mean age was 48.44 ± 10.08 years and mean left ventricular ejection fraction (LVEF) was 42.25 ± 11.1%. ER pattern was more frequent in cases than controls (29 vs 14 patients, P = 0.008). Notched J wave (P = 0.0007) and horizontal ST segment (P = 0.033) were more frequent in cases than controls. On adjusted regression model, LVEF (OR: 0.95, 95% CI: 0.91-0.99, P = 0.015) and ER (OR: 3.39, 95% CI: 1.41-8.12, P = 0.006) could predict VAs, while QTc interval (P = 0.24) and QTd (P = 0.86) did not have predictive effect. Inferior/inferolateral and global ER pattern (P = 0.044 and 0.031 respectively), notched J wave (P = 0.001), increasing J wave amplitude (P = 0.042), and ST segment elevation (P = 0.001) were associated with a higher risk of VAs.

CONCLUSIONS: ER is associated with increased risk of VAs in the setting of acute STEMI.