Yoshiyasu Aizawa1, Seiji Takatsuki2, Takahiko Nishiyama2, Takehiro Kimura2, Shun Kohsaka2, Yoshiaki Kaneko2, Yasuya Inden2, Naohiko Takahashi2, Satoshi Nagase2, Yoshifusa Aizawa2, Keichi Fukuda2. 1. From the Department of Cardiology, Keio University School of Medicine, Tokyo, Japan (Y.A., S.T., T.N., T.K., S.K., K.F.); Department of Cardiovascular Medicine Gunma University Graduate School of Medicine, Japan (Y.K.); Department of Cardiology, Nagoya University Graduate School of Medicine, Japan (Y.I.); Department of Cardiology and Clinical Examination, Faculty of Medicine, Oita University, Japan (N.T.); Division of Arrhythmia and Electrophysiology, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Osaka, Japan (S.N.); and Division of Research and Development, Tachikawa Medical Center, Niigata, Japan (Y.A.). yoshiyaaizawa-circ@umin.ac.jp. 2. From the Department of Cardiology, Keio University School of Medicine, Tokyo, Japan (Y.A., S.T., T.N., T.K., S.K., K.F.); Department of Cardiovascular Medicine Gunma University Graduate School of Medicine, Japan (Y.K.); Department of Cardiology, Nagoya University Graduate School of Medicine, Japan (Y.I.); Department of Cardiology and Clinical Examination, Faculty of Medicine, Oita University, Japan (N.T.); Division of Arrhythmia and Electrophysiology, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Osaka, Japan (S.N.); and Division of Research and Development, Tachikawa Medical Center, Niigata, Japan (Y.A.).
Abstract
BACKGROUND: To know the underlying mechanisms of J waves, the response to atrial pacing was studied in patients with idiopathic ventricular fibrillation (IVF) and patients with non-IVF. METHODS AND RESULTS: In 8 patients with IVF, the J-wave amplitude was measured before, during, and after atrial pacing. All patients had episodes of ventricular fibrillation without structural heart disease. The responses of J waves were compared with those of the 17 non-IVF control subjects who revealed J waves but no history of cardiac arrest and underwent electrophysiological study. The IVF patients were younger than the non-IVF patients (28±10 versus 52±14 years, respectively; P=0.002) and had larger J waves with more extensive distribution. J waves decreased from 0.35±0.26 to 0.22±0.23 mV (P=0.025) when the RR intervals were shortened from 782±88 to 573±162 ms (P=0.001). A decrease (≥0.05 mV) in the J-wave amplitude was observed in 6 of the 8 patients. In addition, 1 patient showed a distinct reduction of J waves in the unipolar epicardial leads. In contrast, J waves were augmented in the 17 non-IVF subjects from 0.27±0.09 to 0.38±0.10 mV (P<0.001): augmented in 9 and unchanged in the 8 subjects. The different response patterns of J waves to rapid pacing suggest different mechanisms: early repolarization in IVF patients and conduction delay in non-IVF patients. CONCLUSIONS: The response to atrial pacing was different between the IVF and non-IVF patients, which suggests the presence of different mechanisms for the genesis of J waves.
BACKGROUND: To know the underlying mechanisms of J waves, the response to atrial pacing was studied in patients with idiopathic ventricular fibrillation (IVF) and patients with non-IVF. METHODS AND RESULTS: In 8 patients with IVF, the J-wave amplitude was measured before, during, and after atrial pacing. All patients had episodes of ventricular fibrillation without structural heart disease. The responses of J waves were compared with those of the 17 non-IVF control subjects who revealed J waves but no history of cardiac arrest and underwent electrophysiological study. The IVFpatients were younger than the non-IVFpatients (28±10 versus 52±14 years, respectively; P=0.002) and had larger J waves with more extensive distribution. J waves decreased from 0.35±0.26 to 0.22±0.23 mV (P=0.025) when the RR intervals were shortened from 782±88 to 573±162 ms (P=0.001). A decrease (≥0.05 mV) in the J-wave amplitude was observed in 6 of the 8 patients. In addition, 1 patient showed a distinct reduction of J waves in the unipolar epicardial leads. In contrast, J waves were augmented in the 17 non-IVF subjects from 0.27±0.09 to 0.38±0.10 mV (P<0.001): augmented in 9 and unchanged in the 8 subjects. The different response patterns of J waves to rapid pacing suggest different mechanisms: early repolarization in IVFpatients and conduction delay in non-IVFpatients. CONCLUSIONS: The response to atrial pacing was different between the IVF and non-IVFpatients, which suggests the presence of different mechanisms for the genesis of J waves.