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Early repolarization (ER) is phenomenon of ECG is noted in 1% to 2% of the adult population. Experimental studies, case reports and clinical studies have shown ER potential arrhythmogenic effect as ventricular fibrillation and sudden cardiac death. ER in the inferior and/or lateral leads has also been shown to increase the risk of future arrhythmic death in subjects of general population without previously documented life-threatening arrhythmic even (ER ECG pattern). Recent studies supported an association between short QT syndrome and early repolarization. The aim of this study was to study the prevalence of ER and its relationship with the QTc interval in healthy subjects.
This study included 80 healthy participants with early repolarization ECG (n=40) and normal ECG (n=40) (82,5 % of whom were men; mean age, 38.9±8.5 years) Study population matched one-to-one according to age and gender. All patients underwent a 12-lead ECG after at least 10 min of resting by sitting. The ECG parameters such as QT, QTc, JT, JTc, QT-apex,JT-apex and T-peak to T-end were utilized in all derivations and mean values were calculated. All electrocardiograms (ECGs) were analyzed for the presence of J-point elevation in inferior (II,III and Avf) and lateral (I, aV L and V4-V6) leads.
There was no statistically significant difference about the demographic characteristics between the 2 groups. Mean heart rate was 69,87±14.89 in early repolarization group and 74,55±13.86 in normal group.There were statistically significant difference with QT,QTc,JT,JTc,QT-apex interval between early repolarization and normal group. Mean QT and QTc interval were 371,69±58,54 and 379,46±21,93 msn in ER, 357,29±28,77 and 410,20±22,50 msn in normal group (respectively p=0,027 and p<0,001). Mean JT and JTc interval were 290,56±28,26 and 331,13±24,59 msn in ER, 273±29,96 and 296,21±22,33 msn in normal group (respectively p=0,013 and p<0,001). Mean QT-apex was 303,13±29,49 in ER,286,99±28,23 msn in normal group (p=0,015).
In our study early repolarization group had shorter QT, QTc interval and JT, JTc, QT-apex interval than normal healthy population with similar heart rate. Future clinical and experimental studies should focus on the relationship between QT interval and increased risk for arrhythmic events in early repolarization.