Introduction
Pulmonary vein isolation (PVI) has become the practical standard for catheter ablation of atrial fibrillation (AF). Transmural ablation lesion is crucial for durable PVI. Insufficient radiofrequency (RF) current delivery may result in incomplete lesion formation and thus require repeat procedures; in contrast, excessive RF current may contribute to serious complications such as steam pop formation, cardiac tamponade, and esophageal injury.
Previous histological studies demonstrated that the left-atrium (LA) and the area surrounding the pulmonary vein (PV) are anatomically heterogenous. Wall thickness (WT) also varies among patients.1,2 Understanding the precise ablation target in each patient will improve the ablation procedure and reduce the risk of adverse events.
Ablation index (AI) is a marker incorporating contact force (CF), time, and power. It is linearly correlated with lesion depth.3 Therefore, the adjustment of AI according to the WT in the area surrounding the PV in each patient seems to yield better therapeutic performance in PVI. Intracardiac echocardiography (ICE) is utilized to visualize the cardiac anatomy during the ablation procedure. We assumed that the WT in the area surrounding the PV could be measured by ICE in a real-time manner and the AI-adjustment based on each patient’s WT would improve the procedure of PVI.
The aims of this study are to measure the WT in the area surrounding the PV using ICE and to assess whether or not WT-based AI-adjustment improves the procedure of PVI.