Maximizing Lesion Depth With the Lattice-Tip Catheter: A Preclinical Comparison of Single, Double, and Mixed...

Combining radiofrequency (RF) and pulsed-field (PF) applications in various combinations, or repeating PF applications, has been reported to augment lesion size and depth. We compared lesion dimensions using single, double, and combined applications of PF and RF for the large-footprint lattice-tip catheter.

Sixteen swine underwent endocardial ablation using the lattice-tip catheter. Four-second PF and 5-second, saline-irrigated, temperature-controlled RF energy were delivered in the ventricles using 1 of 5 different settings: single applications of PF (PF¹-only), single RF (RF¹-only), and 3 sequential settings: PF¹-PF² (2 consecutive PF applications at the same location), PF¹-RF¹ (PF followed by RF), and RF¹-PF¹ (RF followed by PF).

A total of 102 lesions (69 left and 33 right ventricles) were analyzed. Mean lesion depths were 6.8±0.3 mm (PF¹-PF²), 6.6±0.3 mm (RF¹-PF¹), 5.7±0.2 mm (PF¹-only), 5.0±0.3 mm (PF¹-RF¹), and 5.1±0.2 mm (RF¹-only). Mean lesion depths did not differ significantly between PF¹-PF² and either PF¹-only or RF¹-PF¹ (P=0.114 and P=0.986, respectively). However, the variability in depth was significantly smaller in the PF¹-PF² group compared with both PF¹-only and RF¹-PF¹ (P=0.017 and P=0.013, respectively). Only the PF¹-PF² setting produced significantly deeper lesions compared with the RF¹-only and PF¹-RF¹ settings (P=0.015 and P=0.012, respectively). RF lesions exhibited a prominent dark hemorrhagic core and a thin pale rim; PF lesions appeared uniformly pale; and combination lesions demonstrated a central dark zone surrounded by a pale rim of variable thickness.

Repeating PF twice created the optimal combination of greatest depth and least variation compared with all other strategies. RF¹-PF¹ resulted in similar depth, but required toggling between settings and risked thermal adverse events.