Focal atrial tachycardia originating from the distal portion of the left atrial appendage: characteristics and long-term outcomes of radiofrequency ablation.

Aims: The characteristics and response to ablation therapy of focal atrial tachycardia (AT) originating from the distal portion of left atrial appendage (LAAd) are still not quite clear up to now. The goal of this study is to characterize electrocardiographic and electrophysiological features and radiofrequency ablation (RFA) outcomes in patients with focal AT originating from the LAAd.

Methods And Results: Fourteen patients (2.1%) (mean age, 25 ± 10 years; nine women; mean symptom duration, 5 ± 5 years) undergoing RFA of focal AT originating from the LAAd were included out of 668 RFA patients. Activation mapping was performed. P waves were classified as negative, positive, isoelectric, or biphasic. Tachycardia that was incessant in all, demonstrated a characteristic P-wave morphology and endocardial activation pattern: P wave was negative in leads I and aVL, highly positive in the inferior leads, and broad and positive in lead V₁. Radiofrequency ablation was acutely successful in 13 of 14 patients. The endocardial activation time of the successful RFA sites was 47.1 ± 4.3 ms before the onset of P wave. There were no complications in any of the 14 patients and long-term success was achieved in 13 of 13 successful RFA patients during follow-up (5 ± 2 years).

Conclusion: The LAAd is an uncommon site of origin for focal AT (2.1% incidence). In this case series, focal ATs originating from the LAAd had typical electrophysiological and electrocardiographic characteristics. Focal ablation yielded high acute success rate with low rate of recurrence during follow-up.