Inadvertent electrical isolation of the left atrial appendage during catheter ablation of persistent atrial fibrillation
Received 10 August 2009; accepted 26 October 2009. published online 09 November 2009.
Background
Left atrial appendage (LAA) isolation is rare and may be associated with impaired transport function and thromboembolism.
Objective
The purpose of this study was to determine the mechanisms of inadvertent isolation of the LAA during atrial fibrillation (AF) ablation.
Methods
This study consisted of 11 patients (ejection fraction 0.43 ± 0.18, left atrial diameter 51 ± 8 mm) with persistent AF who had LAA conduction block during a procedure for AF (n = 8) or atrial tachycardia (AT) (n = 3).
Results
LAA conduction block occurred during ablation at the Bachmann bundle region in 6 patients, mitral isthmus in 3, LAA base in 2, and coronary sinus in 1. The mean distance from the ablation site to the LAA base was 5.0 ± 1.9 cm. LAA isolation was transient in all 6 patients in whom LAA conduction was monitored and was permanent in the 4 patients in whom conduction was not monitored during energy delivery. The remaining patient was noted to have LAA isolation during a redo procedure before any ablation. Nine of (82%) the 11 patients have remained arrhythmia-free without antiarrhythmic drugs at mean follow-up of 6 ± 7 months, and all have continued taking warfarin.
Conclusion
Electrical isolation of the LAA may occur during ablation of persistent AF and AT even when the ablation site is remote from the LAA. This likely is due to disruption of the Bachmann bundle and its leftward extension, which courses along the anterior left atrium and bifurcates to surround the LAA. Monitoring of LAA conduction during ablation of persistent AF or AT is important in avoiding permanent LAA isolation.
Division of Cardiovascular Medicine, Cardiovascular Center, University of Michigan, Ann Arbor, Michigan
Address reprint requests and correspondence: Dr. Aman Chugh, Division of Cardiovascular Medicine, University of Michigan Hospital, Cardiovascular Center, SPC 5853, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109-5853
Drs. Oral and Morady are co-founders of Ablation Frontiers.
ABSTRACT