Effect of Anterior vs Posterior Dispersive Patch Placement on Radiofrequency Ablation Lesion Size in Swine

Ablation of ventricular tachycardia using radiofrequency (RF) energy can be challenging for deep circuits. Standard RF ablation is monopolar, with energy delivered between the catheter and a dispersive patch (DP). Aligning the DP with the direction of RF application may shift the RF field to create deeper lesions.

The authors sought to compare left ventricular lesion size with concordant (patch oriented in the direction of ablation) versus discordant DP placement in swine.

An irrigated, contact force sensing RF catheter was used to apply lesions to the anterior and posterior left ventricles in swine. Two DPs were attached, and the ground was randomly chosen so that one-half of the lesions were concordant (eg, anterior RF/anterior DP) and one-half were discordant (eg, anterior RF/posterior DP). Ablation parameters otherwise remained constant.

A total of 77 lesions (38 concordant, 39 discordant) in 10 swine were analyzed. Contact force (18.0 ± 3.2 g vs 17.6 ± 3.5 g; P = 0.606) and baseline impedance (111.3 ± 7.5 Ω vs 110.9 ± 7.3 Ω; P = 0.782) were similar between groups. Lesions with concordant compared with discordant DP had greater lesion depth (7.4 ± 1.8 vs 6.1 ± 1.6 mm; P = 0.001) and area (72.5 ± 22.2 mm² vs 59.6 ± 17.5 mm²; P = 0.006).

Placing the DP on the body surface concordant with the direction of RF ablation results in ∼20% increase in lesion depth. This simple modification can be used to enhance RF lesion size.