BACKGROUND: Although J-waves are seen in both patients with idiopathic ventricular fibrillation (IVF) and the general population, their genesis remains unclear. To assess the relationship between J-waves and autonomic tone we investigated the circadian variation of J-waves in individuals with and without IVF. METHODS AND RESULTS: In study 1, we obtained resting 12-lead ECG and Holter ECG recordings in 258 individuals undergoing screening for heart disease. In 60 of these subjects (23.3%), we detected J-waves on Holter ECGs; 40 of them (66.7%) had shown no J-waves on 12-lead ECGs. In study 2, we measured the J-wave amplitude, heart rate (HR), and HR variability [high frequency (HF) and the ratio of low- to high-frequency (LF/HF)] on Holter ECGs recorded in 5 patients with IVF and 20 control subjects who had manifested J-waves. The J-wave amplitude increased at night and decreased during the day in both groups; it was significantly higher in the IVF patients (P<0.0001). In both groups, the J-wave amplitude showed a significant negative correlation with HR and LF/HF and a significant positive correlation with HF. The slope of the J/HR and J/(LF/HF) relationship was significantly steeper in the IVF patients. CONCLUSIONS: The J-wave amplitude was more significantly influenced by the autonomic balance in IVF patients than in the controls. Autonomic J-wave modulation may yield important information on the genesis of J-waves.
BACKGROUND: Although J-waves are seen in both patients with idiopathic ventricular fibrillation (IVF) and the general population, their genesis remains unclear. To assess the relationship between J-waves and autonomic tone we investigated the circadian variation of J-waves in individuals with and without IVF. METHODS AND RESULTS: In study 1, we obtained resting 12-lead ECG and Holter ECG recordings in 258 individuals undergoing screening for heart disease. In 60 of these subjects (23.3%), we detected J-waves on Holter ECGs; 40 of them (66.7%) had shown no J-waves on 12-lead ECGs. In study 2, we measured the J-wave amplitude, heart rate (HR), and HR variability [high frequency (HF) and the ratio of low- to high-frequency (LF/HF)] on Holter ECGs recorded in 5 patients with IVF and 20 control subjects who had manifested J-waves. The J-wave amplitude increased at night and decreased during the day in both groups; it was significantly higher in the IVFpatients (P<0.0001). In both groups, the J-wave amplitude showed a significant negative correlation with HR and LF/HF and a significant positive correlation with HF. The slope of the J/HR and J/(LF/HF) relationship was significantly steeper in the IVFpatients. CONCLUSIONS: The J-wave amplitude was more significantly influenced by the autonomic balance in IVFpatients than in the controls. Autonomic J-wave modulation may yield important information on the genesis of J-waves.