Patients will receive general endotracheal anesthesia or conscious sedation provided by cardiac anesthesiology and usual vascular access for their clinically indicated catheter ablation for AT. Usual diagnostic methods including programmed electrical stimulation for arrhythmia induction and electroanatomic activation and voltage mapping will be performed followed by RFA (using standard-of-care, commercially-available RFA catheters) of any observed AT. After conclusion of AT ablation, transseptal or transbaffle puncture will be performed under fluoroscopic and intracardiac echocardiography guidance to access the left atrium (LA) or pulmonary venous atrium (PVA) if not already done so. PFA will be performed using a pentaspline catheter (Farawave, Boston Scientific) and a steerable sheath to achieve PVI of all veins draining to the LA/PVA with entrance and exit block confirmed at each vein. In patients where PFA is unable to achieve PVI, touch-up RFA will be performed.

After conclusion of AT ablation, transseptal or transbaffle puncture will be performed under fluoroscopic and intracardiac echocardiography guidance to access the left atrium (LA) or pulmonary venous atrium (PVA) if not already done so. PFA will be performed using a pentaspline catheter (Farawave, Boston Scientific) and a steerable sheath to achieve PVI of all veins draining to the LA/PVA with entrance and exit block confirmed at each vein. In patients where PFA is unable to achieve PVI, touch-up RFA will be performed. Programmed atrial stimulation will be performed to investigate for inducible atrial tachycardias. An implantable loop recorder will be placed at the conclusion of the procedure.

Achievement of entrance and exit block to and from all pulmonary veins draining to the left or pulmonary venous atrium.

Time to sustained atrial tachycardia (AT) or atrial fibrillation (AF) lasting 30 seconds or more after a 2 month blanking period.

Composite of stroke, transient ischemic attack, cardiac tamponade requiring percutaneous drainage, phrenic nerve injury >24 hours, atrioesophageal fistula, pulmonary vein stenosis, and/or any bleeding complication requiring blood transfusion.

Daily burden (measured in hours) of AT/AF as measured on an implantable loop recorder after a 2 month blanking period.

Time with sheath/catheter in left atrium or pulmonary venous atrium.