In an in vitro contractile model, the contact force-time integral correlated linearly with radiofrequency lesion volume (P<0.0001 for 20 and 40 W).
Does contact force-time integral (FTI) predict radiofrequency lesion size in an in vitro contractile model?
In an in vitro contractile model, radiofrequency lesion size correlates linearly with the contact force-time integral, demonstrating that constant contact produces larger lesions than intermittent contact despite identical peak forces.
p-value: p=<0.0001
FTI Predicts RF Lesion Size in Contractile Model. Introduction: Electrode tissue contact, radiofrequency (RF) power and duration are major determinants of RF lesion size. Since contact forces (CF) vary in the beating heart, we evaluated contact force–time integral (FTI) as a predictor of lesion size at constant RF power in a contractile bench model simulating the beating heart. Methods and Results: An open‐tip irrigated catheter was attached to a movable mount incorporating a dynamic force sensor allowing closed loop control to achieve desired force variations between the catheter tip and bovine skeletal muscle placed on a ground plate. RF energy (20 and 40 W for 60 seconds, 17 cc/min irrigation) was delivered during (1) constant contact (C) at 20 g, (2) variable contact (V) with a 20 g peak and 10 g nadir, and (3) intermittent contact (I) with a 20 g peak and 0 g nadir with loss of contact. V and I protocols were performed at 50 and 100 catheter movements/min and 2 systole:diastole time ratios (50:50 and 30:70). The area under the CF curve was calculated as the FTI. Measured FTI was highest in C, intermediate during V and lowest during I and correlated linearly with lesion volume (P < 0.0001 for 20 and 40 W). Lesion volume was highest in group C, intermediate in V and lowest in group I (P < 0.05 for C vs V, V vs I, and C vs I). Conclusions: Lesion size correlates linearly with measured contact FTI. Constant contact produces the largest and intermittent contact the smallest lesions despite constant RF power and identical peak contact forces. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1038‐1043, September 2010)
Shah et al. (Fri,) conducted a other in Radiofrequency ablation (in vitro model). Radiofrequency energy delivery with variable contact force vs. Constant contact vs variable vs intermittent contact was evaluated on Lesion volume and its correlation with contact force-time integral (FTI) (p=<0.0001). In an in vitro contractile model, the contact force-time integral correlated linearly with radiofrequency lesion volume (P<0.0001 for 20 and 40 W).