Background: Electrical isolation of the left atrial appendage (LAA) improves outcomes of patients with persistent atrial fibrillation (AF) but may increase the risk of thromboembolism.
Objective: The purpose of this study was to describe a method to map and ablate appendage drivers without complete electrical isolation.
Methods: One hundred thirteen patients underwent an ablation procedure for persistent AF. The procedure was performed during AF and consisted of pulmonary vein and posterior LA isolation as well as ablation of the LAA. The right atrium (RA) was targeted in patients with a right-to-left gradient in cycle length (CL). The end point of appendage ablation was CL slowing or AF termination but not complete isolation.
Results: Among the 113 patients (mean age 64.6 ± 8.6 years; ejection fraction 54% ± 13%; LA diameter 46 ± 6.5 mm), radiofrequency ablation terminated AF in 51 patients (45%). RA ablation was performed in 41 patients (36%) at the index or repeat procedure. The mean AF CL in the RA appendage (RAA) was shorter than that in the LAA (160 ± 32 ms vs 186 ± 29 ms; P < .01) in these patients. The most frequent target in the RA was the RAA (CLs approaching 50-60 ms). Discontinuing radiofrequency ablation upon AF termination or conduction slowing prevented LAA isolation. After a mean follow-up of 24 ± 15 months, 89 patients (78%) remained arrhythmia-free without antiarrhythmic medications.
Conclusion: An ablation strategy guided by the AF CL addresses LAA drivers without complete electrical isolation and also helps identify the RAA as a source of persistent AF.
Keywords: Atrial fibrillation; Catheter ablation; Electrical isolation; Left atrial appendage; Persistent atrial fibrillation; Right atrial appendage.
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