Maximizing Lesion Depth With the Lattice-Tip Catheter: A Preclinical Comparison of Single, Double, and Mixed Pulsed-Field and Radiofrequency Applications

BACKGROUND: 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. METHODS: 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 (PF 1 -only), single RF (RF 1 -only), and 3 sequential settings: PF 1 -PF 2 (2 consecutive PF applications at the same location), PF 1 -RF 1 (PF followed by RF), and RF 1 -PF 1 (RF followed by PF). RESULTS: A total of 102 lesions (69 left and 33 right ventricles) were analyzed. Mean lesion depths were 6.8±0.3 mm (PF 1 -PF 2 ), 6.6±0.3 mm (RF 1 -PF 1 ), 5.7±0.2 mm (PF 1 -only), 5.0±0.3 mm (PF 1 -RF 1 ), and 5.1±0.2 mm (RF 1 -only). Mean lesion depths did not differ significantly between PF 1 -PF 2 and either PF 1 -only or RF 1 -PF 1 ( P =0.114 and P =0.986, respectively). However, the variability in depth was significantly smaller in the PF 1 -PF 2 group compared with both PF 1 -only and RF 1 -PF 1 ( P =0.017 and P =0.013, respectively). Only the PF 1 -PF 2 setting produced significantly deeper lesions compared with the RF 1 -only and PF 1 -RF 1 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. CONCLUSIONS: Repeating PF twice created the optimal combination of greatest depth and least variation compared with all other strategies. RF 1 -PF 1 resulted in similar depth, but required toggling between settings and risked thermal adverse events.