Paced P-wave morphology templates to guide atrial tachycardia localization: A derivation and validation study.

Background: Surface ECG is a useful tool to guide mapping of focal atrial tachycardia (AT).

Objectives: We aimed to construct 12-lead ECG templates for P-wave morphology (PWM) during endocardial pacing from different sites in both atria in patients with no apparent structural heart disease (derivation cohort), with the goal of creating a localization algorithm, which could subsequently be validated in a cohort of patients undergoing catheter ablation of focal AT (validation cohort).

Methods: We prospectively enrolled consecutive patients who underwent electrophysiology study, had no structural heart disease and no atrial enlargement.

High-density electroanatomic activation mapping to guide slow pathway modification in patients with persistent left superior vena cava.

Background: Slow pathway (SP) mapping and modification can be challenging in patients with persistent left superior vena cava (PLSVC) due to anatomic variance of the Koch triangle (KT) and coronary sinus (CS) dilation. Studies using detailed 3-dimensional (3D) electroanatomic mapping (EAM) to investigate conduction characteristics and guide ablation targets in this condition are lacking.

Objectives: The purpose of this study was to describe a novel technique of SP mapping and ablation in sinus rhythm using 3D EAM in patients with PLSVC after validation in a cohort with normal CS anatomy.