Patients
This study protocol consisted of two parts: the first study measured average LA WT (mm) in each anatomical segment for PVI by intra-cardiac echocardiography (ICE) and calculated optimal AI for creating 1-mm transmural lesion (AI/mm). The second study was a prospective randomized study to compare the procedure characteristics of PVI between a force-time integral protocol and a tailored-AI protocol, following the first study (Figure 1).
From May 2018 to September 2019, 100 paroxysmal AF patients undergoing PVI in Fujita Health University were eligible. The review board of Fujita Health University School of Medicine approved the protocol and all patients gave written informed consent. Baseline demographics and clinical information were obtained, and laboratory examinations were performed before the PVI. Left-atrial diameter (LAD), left-ventricular systolic/diastolic dimensions, and left-ventricular ejection fraction (LVEF) were assessed by transthoracic echocardiography. A 3-dimensional image of the LA/PV geometry was reconstructed by cardiac computed tomography (CT) imaging.
All patients received oral anticoagulation therapy with vitamin K antagonist (VKA) or non-vitamin K antagonist oral anticoagulant (NOAC) for ≥4 weeks prior to the catheter ablation. In patients taking VKA, an international normalized ratio was controlled between 2.0 and 3.0. VKA and NOAC were used without interruption during the procedure. Transesophageal echocardiography was performed one day before catheter ablation to detect LA thrombus.
Exclusion criteria were as follows: patients aged under 18 years old, previous ablation procedure for AF, prior prosthetic mitral valve replacement, severe structural cardiac abnormality (e.g., congenital heart disease), severe left ventricular systolic dysfunction (LVEF<35%), severe renal dysfunction (creatinine clearance <15 ml/min)/hemodialysis, LA thrombus detected by TEE, and pregnancy.
All anti-arrhythmic drugs were stopped 5 days prior to the procedure. No patient was being treated with amiodarone.