Mapping and Ablation of Idiopathic Ventricular Fibrillation

Abstract

Background-Ventricular fibrillation is the main mechanism of sudden cardiac death. The feasibility of eliminating recurrent episodes by catheter ablation has not been reported. Methods and Results-Twenty-seven patients without known heart disease (13 men, 14 women, 41Ϯ14 years of age) were studied after being resuscitated from recurrent (10Ϯ12) episodes of primary idiopathic ventricular fibrillation; 23 had received a defibrillator. The first initiating beat of ventricular fibrillation had an identical electrocardiographic morphology and coupling interval (297Ϯ41 ms) to preceding isolated premature beats typically noted in the aftermath of resuscitation. These triggers were localized by mapping the earliest electrical activity and ablated by local radiofrequency delivery. Outcome was assessed by Holter and defibrillator memory interrogation. Premature beats were elicited from the Purkinje conducting system in 23 patients: from the left ventricular septum in 10, from the anterior right ventricle in 9, and from both in 4. The interval from the Purkinje potential to the following myocardial activation varied from 10 to 150 ms during premature beat but was 11Ϯ5 ms during sinus rhythm, indicating location at peripheral Purkinje arborization. The premature beats originated from the right ventricular outflow tract muscle in 4 patients. The accuracy of mapping was confirmed by acute elimination of premature beats during local radiofrequency delivery. During a follow-up of 24Ϯ28 months, 24 patients (89%) had no recurrence of ventricular fibrillation without drug. Conclusions-Primary idiopathic ventricular fibrillation is a syndrome characterized by dominant triggers from the distal Purkinje system. These sources can be eliminated by focal energy delivery.

Elimination of Purkinje Fibers by Electroporation Reduces Ventricular Fibrillation Vulnerability

“…Currently, there is no cure for VF, with only rudimentary treatment options available; thus, sudden cardiac death from VF remains a major worldwide health problem 3, 4. The Purkinje system is implicated in the genesis of primary VF,5, 6, 7 with radiofrequency ablation successfully treating this lethal arrhythmia by targeting triggers, such as a premature ventricular beat emanating from Purkinje tissue 7, 8, 9, 10. However, current radiofrequency ablation approaches to the Purkinje fibers have limitations, particularly because they can only be applied in a point‐to‐point manner, which is tedious and time‐consuming.…”

Successful catheter ablation of focal ventricular fibrillation originating from the right ventricle

“…Haissaguerre et al reported 27 patients who had idiopathic VF, 23 of which had VF arising from the Purkinje conducting system. They reported an 89% success rate for RFA (mean follow-up of 24 months) [4]. These studies support the rationale of pursuing RFA in treating idiopathic VF that is refractory to medical therapy.…”

“…Over the past 6 to 8 years, there has also been the description and growing recognition of patients with VF that has a focal origin. The majority of these seem to originate from the right ventricular outflow tract (RVOT) [3][4][5]. Other foci include sites in the right ventricle (RV) outside the RVOT and sites in the left ventricle (LV).…”

The cardiac IP3 receptor: Uncovering the role of “the other” calcium-release channel

“…This special role played by Purkinje fibers in heart combined with their spatially intermittent isolation from the ventricular mass make them potential arrhythmogenic sources as illustrated by mapping studies in idiopathic ventricular fibrillation, long-QT and Brugada syndromes, and following myocardial infarction [33][34][35]. Several groups have explored the link between Ca 2+ waves and afterdepolarizations in Purkinje fiber cells as a possible mechanism for triggered arrhythmias [36][37][38].…”