Multicatheter Comparison of Very High-Power Short-Duration Radiofrequency Ablation Lesions

Very high-power short-duration (vHPSD) radiofrequency ablation (RFA) is an alternative strategy for pulmonary vein isolation. However, rapid temperature rises may cause complications. The QDOT Micro is designed to detect temperature rises for automatic power and irrigation flow adjustments. We compared how differences in ablation electrode design between three RFA catheters impact vHPSD lesions.

vHPSD RFA was performed within a validated gel tank model. Four-second ablations were delivered with stable contact force using the QDOT, SmartTouch, and TactiFlex SE at 60, 70, 80, and 90 watts, positioned perpendicular (90°), oblique (45°), and parallel (0°) to the ablation target, utilizing 0.9% and 0.45% "half-normal" saline (HNS) irrigation. The SmartTouch and TactiFlex were operated in power-controlled mode, and each configuration was repeated three times, with images captured every second to characterize lesions.

In total, 216 vHPSD lesions were delivered. At 90 W, 90°, and 0.9% saline, the QDOT produced lesions with a mean depth of 1.93 mm. The TactiFlex produced shallower lesions, with a mean depth of 1.88 mm (p = 0.02), and the SmartTouch produced the deepest, with a mean depth of 2.37 mm (p < 0.001). The mean diameter of QDOT lesions, at 4.63 mm, was comparable to TactiFlex lesions (4.58 mm, p = 0.8), whilst the SmartTouch lesions were significantly wider than both the QDOT and TactiFlex (6.04 mm, p < 0.001). Steam-pop risk, based on lesion temperature, was lowest for the TactiFlex.

vHPSD lesions produced with the QDOT achieved greater dimensions and temperatures than those with the TactiFlex under controlled conditions, suggesting a difference in the cooling profile of the ablation electrodes. vHPSD with the SmartTouch or 0.45% HNS are likely to increase the risk of steam pops.