Focal Atrial Tachycardia Originating from the Left Atrial Appendage: Electrocardiographic and Electrophysiologic Characterization and Long‐Term Outcomes of Radiofrequency Ablation

Abstract

Introduction: This study sought to investigate electrophysiologic characteristics and radiofrequency ablation (RFA) in patients with focal atrial tachycardia (AT) arising from the left atrial appendage (LAA). Methods: This study included seven patients undergoing RFA with focal AT. Activation mapping was performed during tachycardia to identify an earlier activation in the left atria and the LAA. The atrial appendage angiography was performed to identify the origin in the LAA before and after RFA. Results: AT occurred spontaneously or was induced by isoproterenol infusion rather than programmed extrastimulation and burst atrial pacing in any patient. The tachycardia demonstrated a characteristic P‐wave morphology and endocardial activation pattern. The P wave was highly positive in inferior leads in all patients. Lead V₁ showed upright or biphasic (±) component in all patients. Lead V₂–V₆ showed an isoelectric component in five patients or an upright component with low amplitude (Conclusions: The LAA is an uncommon site of origin for focal AT (3%). There were consistent P‐wave morphology and endocardial activation associated with this type of AT. The LAA focal ablation is safe and effective. Long‐term success was achieved with focal ablation in all patients.