Arrhythmia Termination Versus Elimination of Dormant Pulmonary Vein Conduction as a Procedural End Point of Catheter Ablation for Paroxysmal Atrial Fibrillation: A Prospective Randomized Trial

Abstract

Background: Pulmonary vein isolation (PVI) is still associated with a substantial number of arrhythmia recurrences in paroxysmal atrial fibrillation (AF). This prospective, randomized study aimed to compare 2 different procedural strategies.

Methods and results: A total of 152 patients undergoing de novo ablation for paroxysmal AF were randomized to 2 different treatment arms. The procedure in group A consisted of PVI exclusively. In this group, all isolated PVs were challenged with adenosine to reveal and ablate dormant conduction. In group B, PVI was performed with the patient either in spontaneous or in induced AF. If AF did not terminate with PVI, ablation was continued by targeting extra-PV AF sources with the desired procedural end point of termination to sinus rhythm. Primary study end point was freedom from arrhythmia during 1-year follow-up. In group A, adenosine provoked dormant conduction in 31 (41%) patients with a mean of 1.6±0.8 transiently recovered PVs per patient. Termination of AF during PVI was observed in 31 (65%) patients, whereas AF persisted afterward in 17 (35%) patients. AF termination occurred in 13 (76%) patients by AF source ablation. After 1-year follow-up, significantly more group B patients were free of arrhythmia recurrences (87 versus 68%; P=0.006). During redo ablation, the rate of PV reconduction did not differ between both groups (group A: 55% versus group B: 61%; P=0.25).

Conclusions: Elimination of extra-PV AF sources after PVI is superior to sole PV isolation with the adjunct of abolishing potential dormant conduction.

Clinical trial registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02238392.

Keywords: arrhythmias, cardiac; atrial fibrillation; catheter ablation; follow-up studies; pulmonary veins.

Figure 1.

A, Atrial fibrillation termination into sinus rhythm during ablation of an extra–pulmonary vein (PV) source at the anterior left atrium. The rapid local activity in the ablation catheter with complex fractionated electrogram configuration and activation gradient between distal and proximal bipoles. Immediately before atrial fibrillation terminates, the local fractionated electrograms convert into more discrete signals along with local cycle length slowing. B, Induction of dormant conduction induced by the application of 15-mg adenosine. C, Adenosine application after electric isolation of a left superior PV showing dissociated activity. With the occurrence of complete AV block, the dissociated rhythm disappeared and the PV remained isolated without the occurrence of dormant conduction. II, III, V₁, and V₄ are surface ECG leads; CS indicates coronary sinus; LS, Lasso catheter (placed in the left atrial appendage); and Map d and p, distal and proximal ablation catheter bipoles.

Figure 2.

Kaplan–Meier arrhythmia-free survival estimation during an overall mean follow-up of 18.7±4.5 mo after a single procedure. The vertical line indicates a follow-up duration of 1 y. Group B patients had a significantly better outcome than group A patients (P=0.006 based on 12 mo of follow-up; P=0.001 based on overall follow-up).

Figure 3.

Kaplan–Meier arrhythmia-free survival estimation after final procedure (mean of 1.3±0.7 procedures with an overall follow-up duration of 20.3±4.6 mo).