Radiofrequency Catheter Ablation of Chronic Atrial Fibrillation Guided by Complex Electrograms

Abstract

Background-Radiofrequency catheter ablation of atrial fibrillation (AF) guided by complex fractionated atrial electrograms has been reported to eliminate AF in a large proportion of patients. However, only a small number of patients with chronic AF have been included in previous studies. Methods and Results-In 100 patients (mean age, 57Ϯ11 years) with chronic AF, radiofrequency ablation was performed to target complex fractionated atrial electrograms at the pulmonary vein ostial and antral areas, various regions of the left atrium, and the coronary sinus until AF terminated or all identified complex fractionated atrial electrograms were eliminated. Ablation sites consisted of Ն1 pulmonary vein in 46% of patients; the left atrial septum, roof, or anterior wall in all; and the coronary sinus in 55%. During 14Ϯ7 months of follow-up after a single ablation procedure, 33% of patients were in sinus rhythm without antiarrhythmic drugs, 38% had AF, 17% had both AF and atrial flutter, 9% had persistent atrial flutter, and 3% had paroxysmal AF on antiarrhythmic drugs. A second ablation procedure was performed in 44% of patients. Pulmonary vein tachycardia was found in all patients in both previously targeted and nontargeted pulmonary veins. There were multiple macroreentrant circuits in the majority of patients with atrial flutter. At 13Ϯ7 months after the last ablation procedure, 57% of patients were in sinus rhythm without antiarrhythmic drugs, 32% had persistent AF, 6% had paroxysmal AF, and 5% had atrial flutter. Conclusions-Modest short-term efficacy is achievable with radiofrequency ablation of chronic AF guided by complex fractionated atrial electrograms, but only after a second ablation procedure in Ͼ40% of patients. Rapid activity in the pulmonary veins and multiple macroreentrant circuits are common mechanisms of recurrent atrial arrhythmias. (Circulation.

Mechanisms of Atrial Fibrillation – Reentry, Rotors and Reality

“…In a subsequent study of 100 patients with chronic AF who underwent CFAE ablation alone, after an average follow-up of 14 months, only 33 % of patients remained free of arrhythmia without antiarrhythmic medications; 55 % of patients developed recurrence of AF; and 44 % of patients required a repeat ablation procedure. 61 In another study of 77 patients with persistent AF comparing CFAE ablation alone with CFAE ablation with PVI, over an average follow-up period of 13 months, 41 % of patients who had CFAE ablation alone had recurrence of AF compared with 9 % of patients who had CFAE ablation with PVI (p=0.008). 62 Di Biase et al randomised 103 patients with paroxysmal AF to CFAE ablation, PVI, or the combination of CFAE ablation and PVI and found that freedom from atrial tachyarrhythmia at one year was present in only 23 % of patients who underwent CFAE ablation alone compared with 89 % in the PVI group, and 91 % in the CFAE plus PVI group (p<0.001 for a three-way comparison).…”

“…Observations that CFAE ablation without PVI results in very high rates of AF recurrence 54,[61][62][63]65 suggest that CFAEs are not drivers of AF. In fact, the vast majority of areas of observed fractionation are actually functional and passive electrophysiological manifestations.…”

Outcomes of long-standing persistent atrial fibrillation ablation: A systematic review

“…Four studies have utilized CFAE ablation alone in persistent/long-standing persistent AF in a total of 270 patients 4,6,27,28 . It is important to note that signals were not objectively characterized using 3D mapping and signal detection algorithms, but instead subjectively assessed by the respective operators.…”

“…It is important to note that signals were not objectively characterized using 3D mapping and signal detection algorithms, but instead subjectively assessed by the respective operators. Nademanee et al 28 were the first to purport the success of pure CFAE ablation but their results have not been reproduced 4,6,27 . Reasons for this may include: operator experience, total ablation time differences, the subjectivity of what represented an 'important' electrogram and finally, the severity of disease in the cohort.…”

Ablation of Atrial Fibrillation

“…Until recent advances in mapping, ablation of AF "substrate" was synonymous with extensive lesions, with variable results 19,[60][61][62] and damage to atrial function 63 . One perceptible trend is to perform less extensive AF ablation, because widespread ablation may increase complications and reduce atrial function 63 , from the disappointing efficacy of extensive ablation of complex fractionated electrograms 19,61,62 and from mechanistic trends to identify targets amenable to localized ablation lesions.…”