Background
Radiofrequency (RF) catheter ablation is a well-developed treatment of
atrial fibrillation (AF) (1,2). AF frequently originates from atrial
muscular sleeves that extend into the thoracic veins such as the
pulmonary veins (PV) and superior vena cava (SVC) (1,3,4) and the
electrical isolation between the left atrium and these thoracic veins is
the cornerstone strategy of AF ablation (3). An insufficient
lesion-creation and conduction recurrence lead to the recurrence of
arrhythmias (5~7). Therefore, a durable lesion-formation
is a key factor for RF ablation. Lesion-formation depends on several
factors such as the catheter contact force (CF), RF delivery time, and
power (8). The ablation index (AI), a novel marker for incorporating the
CF, RF delivery time, and power in a weighted formula, has been reported
to be useful for a durable PVI (9~11). Several studies
have reported the optimal value of the AI for PV isolation (PVI) and
cavotricuspid isthmus line (CTI) ablation (12~14).
However, no study has reported the
optimal value of the AI for the SVC isolation (SVCI). In this study, we
aimed to investigate the optimal AI for the SVCI.