Electrophysiologic characteristics and catheter ablation of focal atrial tachycardia with more than one focus

Background: Information about the electrophysiologic characteristics and long-term outcome of catheter ablation in patients with multiple focal atrial tachycardia (AT) is limited. Objective: The purpose of this study was to investigate the electrophysiologic characteristics and long-term outcome of catheter ablation in patients with multiple focal AT. Methods: Two hundred fifty-one patients who were referred for radiofrequency catheter ablation of focal AT were included for analysis. Results: Forty-four patients who had focal AT with more than one focus were identified. Comparing focal AT with a single focus to that with more than one focus, the existence of a left atrial focus, cardiovascular comorbidity, nonparoxysmal tachycardia, shortest tachycardia cycle length, success rate of the ablation, and procedure time all differed. Multivariate logistic analysis revealed that a left atrial focus, cardiovascular comorbidity, and shortest tachycardia cycle length were independent predictors of focal AT with more than one focus. Noncontact mapping of the right atrium revealed larger low-voltage zone and longer total activation time for focal AT with more than one focus. Patients who had focal AT with more than one focus and a failed ablation had a greater number of focal ATs and mechanisms of nonparoxysmal tachycardia. Multivariate logistic analysis revealed that only the number of focal ATs predicted a failed ablation. Conclusion: Focal ATs with more than one focus have different electrophysiologic characteristics. This study provides new insight into the development and atrial remodeling of focal AT with multiple foci.