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.

Anteroseptal basal right ventricular entrainment is simple and superior to apical entrainment in identifying mechanism of supraventricular tachycardia.

Background: Differentiation between atrioventricular nodal reentry tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) can be sometimes challenging. Apical right ventricular (RV) entrainment can help in differentiation; however, it has some fallacies. We thought to compare the accuracy of anteroseptal basal RV entrainment to RV apical entrainment in identifying the mechanism of supraventricular tachycardia (SVT).