Characteristic of the prevalence of J wave in apparently healthy Chinese adults.

Background: The J wave has been seen in idiopathic ventricular fibrillation, Brugada syndrome, and early repolarization syndrome. Although these conditions share some ECG features, the clinical consequences are markedly different. J wave presentation in healthy subjects is not a rare phenomenon, although its characteristics are poorly understood. The aim of this study was to investigate the prevalence and the characteristics of the J wave in apparently healthy Chinese adults.

Methods: The study was comprised of 1817 consecutive healthy Chinese subjects undergoing annual routine medical examination from April 2006 to July 2006, including 1131 men and 686 women. Routine medical examination including ECG was performed. J wave was defined as a wave on the ECG that followed the QRS complex with amplitude of at least 0.05 mV for 0.03 sec.

Results: The prevalence of the J wave in all subjects was 7.26%. The prevalence of the J wave in males was significantly higher than in females (10.52 vs. 1.89%, p<0.01). The incidence of the J wave in the inferior leads (II, III, avF), right precordial leads (V1-V3), and left precordial leads (V4-V6) was 4.57, 0.50, and 2.20%, respectively. The J wave prevalence in the inferior leads was significantly higher than in the left and right precordial leads (both p<0.05). Moreover, the prevalence of the J wave had a positive correlation with age in all subjects (r=0.78, p<0.01).

Conclusions: J wave presentation on the ECG of apparently healthy people is not a rare phenomenon and is more likely to be found in the elderly, in males, and more frequently occurs in the inferior leads than in left and right precordial leads.