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 (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).

RESULTS

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.

CONCLUSIONS

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.