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Early repolarization (ER) has been linked to the risk of sudden cardiac death (SCD) in the general population, although controversy remains regarding risks across various subgroups.The purpose of this study was to investigate whether age and sex influence the prognostic significance of ER.We evaluated the 12-lead electrocardiograms of 6631 Finnish general population subjects age ≥30 years (mean age 50.1 ± 13.9 years; 44.5% men) for the presence of ER (J-point elevation ≥0.1 mV in ≥2 inferior/lateral leads) and followed them for 24.4 ± 10.3 years. We analyzed the association between ER and the risk of SCD, cardiac death, and all-cause mortality in subgroups according to age (50 or ≥50 years) and sex.ER was present in 367 of the 3305 subjects age50 years and in 426 of 3326 subjects ≥50 years. ER was not associated with any of the endpoints in the entire study population. After adjusting for clinical factors, ER was associated with SCD (hazard ratio [HR] 1.88; 95% confidence interval [CI] 1.16-3.07) in subjects50 but not in older subjects (interaction between ER and age group, P = .048). In the younger subgroup, women with ER had a high risk of SCD (HR 4.11; 95% CI 1.41-12.03), whereas among men ER was not associated with SCD. Finally, ER was not associated with cardiac mortality or all-cause mortality in either age group.ER is associated with SCD in subjects younger than 50 years, particularly in women, but not in subjects 50 years and older.

Background QRS transition zone is related to the electrical axis of the heart in the horizontal plane and is easily determined from the precordial leads of a standard 12-lead ECG. However, whether delayed QRS transition, or clockwise rotation of the heart, carries prognostic implications and predicts sudden cardiac death (SCD) is unclear. Objective The purpose of this study was to study whether delayed transition is associated with mortality and SCD. Methods We evaluated 12-lead ECGs of 10,815 Finnish middle-aged subjects from the general population (52% men, mean age 44 ± 8.5 years) and followed them for 30 ± 11 years. Main end-points were mortality and SCD. Results Delayed QRS transition at lead V 4 or later occurred in 1770 subjects (16.4%) and markedly delayed transition at lead V 5 or later in 146 subjects (1.3%). Delayed transition zone was associated with older age, male gender, higher body mass index, hypertension, baseline cardiovascular disease, leftward shift of the frontal QRS axis, wider QRS-T angle, and ECG left ventricular hypertrophy. After adjusting for several clinical and ECG variables, delayed transition was associated with overall mortality (hazard ratio [HR] 1.15, 95% confidence interval [CI] 1.07–1.22, P P = .029). Markedly delayed transition at V 5 or later predicted significantly SCD (HR 1.89, 95% CI 1.18–3.03, P = .008) and all-cause mortality (HR 1.30, 95% CI 1.07–1.58, P = .01). However, further adjustments for repolarization abnormalities attenuated this effect. Conclusion Delayed QRS transition in the precordial leads of an ECG seems to be a novel ECG risk marker for SCD. In particular, markedly delayed transition was associated with significantly increased risk of SCD, independent of confounding factors.

Background Early repolarization (ER) in the inferior/lateral leads predicts mortality, but whether ER is a specific sign of increased risk for arrhythmic events is not known. Objective The purpose of this study was to study the association of ER and arrhythmic events and nonarrhythmic morbidity and mortality. Methods We assessed the prognostic significance of ER in a community-based general population of 10,846 middle-aged subjects (mean age 44 ± 8 years). The end-points were sustained ventricular tachycardia or resuscitated ventricular fibrillation (VT-VF), arrhythmic death, nonarrhythmic cardiac death, new-onset atrial fibrillation (AF), hospitalization for congestive heart failure, or coronary artery disease during mean follow-up of 30 ± 11 years. ER was defined as ≥0.1-mV elevation of J point in either inferior or lateral leads. Results After including all risk factors of cardiac mortality and morbidity in Cox regression analysis, inferior ER (prevalence 3.5%) predicted VF-VT events (n = 108 [1.0%]) with a hazard ratio (HR) of 2.2 (95% confidence interval [CI] 1.1–4.5, P = .03) but not nonarrhythmic cardiac death (n = 1235 [12.2%]), AF (n = 1659 [15.2%]), congestive heart failure (n = 1752 [16.1%]), or coronary artery disease (n = 3592 [32.9%]) ( P = NS for all). Inferior ER predicted arrhythmic death in cases without other QRS complex abnormalities (multivariate HR 1.68, 95 % CI 1.10–2.58, P = .02) but not in those with ER and other coexisting abnormalities in QRS morphology (HR 1.30, 95% CI 0.86–1.96, P = .22). Conclusion ER in the inferior leads, especially in cases without other QRS complex abnormalities, predicts the occurrence of VT-VF but not nonarrhythmic cardiac events, suggesting that ER is a specific sign of increased vulnerability to ventricular tachyarrhythmias.

Background Prolongation of initial ventricular depolarization on the 12-lead electrocardiogram (ECG), or delayed intrinsicoid deflection (DID), can indicate left ventricular hypertrophy (LVH). The possibility that this marker could convey distinct risk of sudden cardiac arrest (SCA) has not been evaluated. Objective To evaluate the association of DID and SCA in the community. Methods In the ongoing prospective, population-based Oregon Sudden Unexpected Death Study (Oregon SUDS; catchment area approximately 1 million), SCA cases were compared to geographic controls with no SCA. Archived ECGs (closest and unrelated to SCA event for cases) were evaluated for the presence of DID, defined as ≥0.05 second in leads V 5 or V 6 . Left ventricular (LV) mass and function were evaluated from archived echocardiograms. Results SCA cases (n = 272, 68.7 ± 14.6 years, 63.6% male) as compared to controls (n = 351, 67.6 ± 11.4 years, 63.3% male) were more likely to have DID on ECG (28.3% vs 17.1%, P = .001). DID was associated with increased SCA odds (odds ratio [OR] 1.92; 95% confidence interval [CI] 1.31–2.81; P = .001), but showed poor correlation with LV mass and echocardiographic LVH (kappa 0.13). In multivariate analysis adjusted for clinical and ECG markers, reduced LV ejection fraction, and echocardiographic LVH, DID remained an independent predictor of SCA (OR 1.82; 95% CI 1.12–2.97; P = .016). Additionally, in a sensitivity analysis restricted to narrow QRS, DID and ECG LVH by voltage were each independently associated with SCA risk. Conclusion DID was associated with increased SCA risk independent of echocardiographic LVH, ECG LVH, and reduced LV ejection fraction, potentially reflecting unique electrical remodeling that warrants further investigation.