Ablation protocol
RF lesions were created on the LV epicardium with a Rhythmia HDx™
Mapping System (Boston Scientific, Maple Grove, MN, USA). The RF
application was delivered with a constant power of 30 watts and a
duration of 30 seconds. CF (0, 5, 10, 20, and 30 g) and the catheter
contact angle (30°, 45°, and 90°) were changed in each set (total 120
lesions, n=8 each, Figure 2). The same experiment was performed with 2
different ablation catheters. The LI increases as the catheter contacts
the tissue, and the LI decreases with the RF application. We defined the
value of the LI increase above the baseline LI by the catheter contact
as the LI rose and the absolute decrease in LI by the RF application as
the LI dropped. The proportional values of the LI parameters were also
evaluated to compare the 2 different catheters. The %LI rise was
calculated as the LI rise divided by the baseline LI, and the %LI drop
was calculated as the LI drop divided by the baseline LI.