Operator-blinded contact force monitoring during pulmonary vein isolation using conventional and steerable sheaths

We performed contact force (CF) monitoring during pulmonary vein (PV) isolation to evaluate CF according to sheath type, catheter position, and inadequate ablation.

Thirty consecutive patients (paroxysmal atrial fibrillation, 23; CHADS2 score, 0.5 ± 0.7; age, 56 ± 10 years) who underwent PV isolation using a CF-sensing catheter were included. Data for operator-blinded CF, impedance, and duration of the "first touch" (first round of ablation in each PV) was collected. We compared the CF, maximum CF, force-time integral, average impedance, and impedance drop (Δ impedance) between different sheaths (Swartz™ vs. Agilis™) in 12 different catheter positions, and in inadequate first touches requiring additional ablation.

A total of 1283 ablation points (Swartz™, 620 points; Agilis™, 663 points) were evaluated. The average CF was significantly higher in the Agilis™ group (17.8 ± 13.0 g) than the Swartz™ group (15.0 ± 12.4 g; P < 0.001), especially in the anterior, inferior-anterior, and inferior-posterior sections of the right PV, and the top of the roof, and calina of the left PV. The Δ impedance showed a mildly significant negative relationship with the average CF (r=-0.206; P<0.001) and with the force-time integral (r = -0.279; P < 0.001). Compared to first touches, the average CF and Δ impedance were significantly smaller in inadequate first touches in the Swartz™ group, but not in the Agilis™ group.

CF for PV isolation was significantly different depending on the position of the catheter and the type of sheath.