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.