Elsevier

Heart Rhythm

Volume 1, Issue 2, July 2004, Pages 197-202
Heart Rhythm

Mechanisms of recurrent atrial fibrillation after pulmonary vein isolation by segmental ostial ablation

https://doi.org/10.1016/j.hrthm.2004.03.071Get rights and content

Abstract

Objectives

The aim of this study was to determine the mechanisms responsible for recurrent atrial fibrillation (AF) after pulmonary vein isolation (PV) by segmental ostial ablation.

Background

Recovery of conduction into a previously isolated PV is a common observation when there is recurrent AF soon after segmental ostial ablation. However, the mechanisms of recurrent AF have been unclear.

Methods

A repeat ablation procedure was performed in 50 patients who had recurrent paroxysmal AF at a mean of 7 ± 6 months after segmental ostial ablation to isolate the PVs. During the repeat procedure, a ring catheter was inserted into each PV during sinus rhythm and AF to determine whether the veins were still isolated and, if not, whether there were PV tachycardias with a cycle length shorter than in the adjacent left atrium during AF.

Results

There was recovery of conduction over a previously ablated muscle fascicle in ≥1 PV in 49 patients (98%). There were 10 ± 2 episodes of PV tachycardia per minute in 36 (72%) of the 50 patients during AF. Repeat ablation was performed by segmental ostial ablation (23 patients) or by left atrial catheter ablation to encircle the left- and right-sided PVs 1 to 2 cm from the ostia, with additional ablation lines in the posterior left atrium and mitral isthmus (27 patients). At 6-month follow-up, among 23 patients who underwent repeat ablation by segmental ostial ablation, AF recurred in 4 (21%) of the 19 patients who had PV tachycardias and in 3 (75%) of the 4 patients who did not (P = .03). Among the 27 patients who underwent left atrial ablation, AF recurred in 2 (12%) of the 17 patients who had PV tachycardias and in 1 (10%) of the 10 patients who did not (P = 0.7).

Conclusions

Recovery of conduction in previously ablated muscle fascicles is a common finding in patients with recurrent AF after segmental ostial ablation. The efficacy of repeat segmental ostial ablation depends on the presence of PV tachycardias, whereas left atrial ablation is effective regardless of whether PV tachycardias are present or not during AF.

Section snippets

Study subjects

A repeat ablation procedure was offered to 76 patients who had recurrent episodes of paroxysmal AF during a mean follow-up of 7 ± 6 months after PV isolation by segmental ostial ablation. The 76 patients were part of a pool of 208 patients who underwent segmental ostial ablation. The subjects of this study were 50 of the 76 patients with recurrent AF who agreed to a repeat ablation procedure. Among the remaining 26 patients, 15 either had improvement in the frequency of episodes of AF or were

Recovery of conduction in a previously isolated PV

Among the 50 patients who underwent a repeat ablation procedure, there was recovery of conduction into ≥1 PV in 49 patients (98%). Among the 164 previously isolated PVs, recovery of conduction into a PV was observed in 40 (80%) of the 50 left superior PVs, 38 (76%) of the 50 right superior PVs, 28 (56%) of the 50 left inferior PVs, and 15 (75%) of the 20 right inferior PVs.

PV tachycardia

A PV tachycardia was present in ≥1 PV in 36 (72%) of the 50 patients during AF (Figure 1). PV tachycardias were observed

Main findings

The results of this study demonstrate that recovery of conduction into a previously isolated PV occurred in >95% of patients with recurrent AF after segmental ostial ablation for paroxysmal AF. However, PV tachycardias, which may play a role in the maintenance of AF, were observed in only 70% of patients. Freedom from recurrent AF after repeat PV isolation by segmental ostial ablation was dependent on the presence of PV tachycardias, whereas left atrial catheter ablation was effective

Conclusion

The findings of this study provide insight into the mechanisms of AF and explain why PV isolation by segmental ostial ablation is not effective in 30% to 40% of patients with paroxysmal AF. AF is a multifactorial process, and the PVs do not play a critical role in generating AF in all patients with paroxysmal AF. The efficacy of PV isolation by segmental ostial ablation depends on the presence of PV tachycardias during episodes of paroxysmal AF. In contrast, the efficacy of left atrial ablation

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  • Cited by (84)

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    Supported by the Ellen and Robert Thompson Atrial Fibrillation Research Fund.

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