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

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 (