• Yoshifusa Aizawa, Akinori Sato, Hiroshi Watanabe, Masaomi Chinushi, Hiroshi Furushima, Minoru Horie, Yoshiaki Kaneko, Tsutomu Imaizumi, Kimie Okubo, Ichiro Watanabe, Tsuyoshi Shinozaki, Yoshiyasu Aizawa, Keiichi Fukuda, Kunitake Joo, and Michel Haissaguerre.
• Niigata University Graduate School of Medical and Dental Science, Niigata, Japan. aizaways@med.niigata-u.ac.jp
• J. Am. Coll. Cardiol. 2012 May 29; 59 (22): 1948-53.

ObjectivesThis study evaluated the pause-dependency of the J-wave to characterize this phenomenon in idiopathic ventricular fibrillation (VF).BackgroundThe J-wave can be found in apparently healthy subjects and in patients at risk for sudden cardiac death, and risk stratification is therefore needed.MethodsForty patients with J-wave-associated idiopathic VF were studied for J waves with special reference concerning pause-dependent augmentation. J waves were defined as those ≥0.1 mV above the isoelectric line and were compared with 76 non-VF patients of comparable age and sex.ResultsThe J-wave was larger in patients with idiopathic VF than in the controls: 0.360 ± 0.181 mV versus 0.192 ± 0.064 mV (p = 0.0011). J waves were augmented during storms of VF (n = 9 [22.5%]), which was controlled by isoproterenol; they disappeared within weeks in 5 patients. In addition, sudden prolongation of the R-R interval was observed in 27 patients induced by benign arrhythmia, and 15 patients (55.6%) demonstrated pause-dependent augmentation (from 0.391 ± 0.126 mV to 0.549 ± 0.220 mV; p < 0.0001). In the other 12 experimental subjects and in the 76 control subjects, J waves remained unchanged. Pause-dependent augmentation of J waves was detected in 55.6% (sensitivity) but was specific (100%) in the patients with idiopathic VF with high positive (100%) and negative (86.4%) predictive values.ConclusionsPause-dependent augmentation of J waves was confirmed in about one-half of the patients with idiopathic VF after sudden R-R prolongation. Such dynamicity of J waves was specific to idiopathic VF and may be used for risk stratification.Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

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