Electrophysiological Findings in Idiopathic Recurrent Ventricular Fibrillation: Special Reference to Mode of Induction, Drug Testing, and Long‐Term Outcomes

Abstract

Electrophysiological studies can be useful in the presence of idiopathic ventricular fibrillation (VF) and may be used when selecting antiarrhythmic drugs. However, the yield, the mode, and the long-term reproducibility of the induction of VF have not yet been fully elucidated. Eight patients with idiopathic VF underwent electrophysiological study. The mean age (+/- SD) was 45 +/- 17 years. Six were males and two were females. Diagnosis was done by exclusion. VF was induced in 6 (75%) of 8 patients using double extra stimuli at coupling intervals of 233 +/- 39 and 191 +/- 20 ms for the first and second extra stimuli, respectively. Of note, VF was induced by stimulation exclusively at the origin of the premature ventricular beat, which was the first complex of VF in two patients. In another patient, VF was initiated by two premature stimuli and also by a pause produced by rapid pacing. The inducibility of VF was reproduced 9-18 months after the first induction in all of the four patients studied. When the ability of antiarrhythmic drugs to suppress VF inducibility was confirmed, no recurrence was observed during the follow-up period of 40-160 months, but a recurrence of VF was observed in one of two nonresponders. In one patient, amiodarone administration failed in preventing VF induction 9 months after initiation of therapy, and reassessment of long-term drug-efficacy might be indicated in some patients. In conclusion, idiopathic VF was highly inducible (75%) with double extra stimuli. In this study, it was induced from a specific site (2/8) or by a pause (1/8). Induction of VF seemed to be reproduced 9-18 months after the first study. The outcome was considered favorable when the inducibility of VF was suppressed by antiarrhythmic drugs.

Inferior and Lateral Electrocardiographic Repolarization Abnormalities in Brugada Syndrome

“…Aizawa et al 11 reported several cases of idiopathic ventricular fibrillation in Japanese men that were associated with a notch in the late part of the QRS complex in the inferior leads.…”

“…8 -11 In 4 patients, the administration of a class I AAD augmented the J wave and ST segment elevation (8.9), but it failed to do so in 4 other patients. 10,11 Very recently, Haissaguerre et al 12 reported a multicenter study of 206 patients with idiopathic ventricular fibrillation. They found that early repolarization pattern in the inferior or lateral leads was more frequent among patients with idiopathic ventricular fibrillation as in a healthy control group (31% versus 5%, PϽ0.001).…”

Dynamicity of the J-Wave in Idiopathic Ventricular Fibrillation With a Special Reference to Pause-Dependent Augmentation of the J-Wave

“…Since our first reports of the association of the J-wave with idiopathic VF (6,7,15), we have studied pausedependent augmentation of the J-wave and have been collecting case data regarding idiopathic VF. In this study, we analyzed the pause-induced dynamicity of the J-wave in patients with J-wave-associated idiopathic VF and compared this with control subjects to propose another characteristic of J waves in idiopathic VF.…”

Significance of Early Onset and Progressive Increase of Activation Delay During Premature Stimulation in Brugada Syndrome

“…In BS, VF is more easily induced by programmed electrical stimulation during an EPS, 1,7,8 especially from the RVOT. 9,10 We often observed marked prolongation of St-QRS at a short coupling interval of extrastimulus preceding VF induction ( Figure 5).…”

“…On the other hand, the His-ventricular (HV) interval in BS is often prolonged, and VF can be induced by programmed electrical stimulation during an electrophysiologic study (EPS), 1,7,8 especially from the right ventricular outflow tract (RVOT). 9,10 This suggests that a depolarization abnormality (conduction disturbance) contributes to the arrhythmogenesis of BS.…”