Ultra-Low Temperature Cryoablation Combined With Pulsed Field Ablation in a Swine Ventricular Infarct Model.

BACKGROUND

Treatment of ventricular arrhythmias with radiofrequency catheter ablation can be challenging due to insufficient ablation efficacy in scar. The performance of ultra-low temperature cryoablation (ULTC) and combined ULTC + pulsed field ablation (PFA) has not been studied in ventricular tissue.

OBJECTIVES

This study sought to compare ventricular lesion size between ULTC alone and combined ULTC+PFA.

METHODS

A total of 5 swine underwent chronic infarction via 120-minute balloon occlusion of the left anterior descending coronary artery. Three ablation approaches were tested: single 2-minute freeze (ULTC-1), 2 sequential 2-minute freezes delivered in a freeze-thaw-freeze cycle (ULTC-2), and a single 2-minute freeze with 8 PFA trains (ULTC-1+PFA).

RESULTS

A total of 36 lesions (7 ULTC-1, 14 ULTC-2, 15 ULTC-1+PFA lesions) were applied to the left ventricular endocardium in 5 swine. Median (Q1-Q3) width was 9 (7-13) mm in healthy tissue and 11 (9-14) mm in scar (P = 0.18). In both healthy and scar tissue, lesion width was larger with ULTC-2 and with ULTC-1+PFA when compared with ULTC-1 alone. Lesion depth was 11 (9-15) mm in healthy tissue and 11 (8-13) mm in scar (P = 0.57). Lesion depth trended deeper with ULTC-2 and with ULTC-1+PFA. Within scar, zero of the ULTC-1, 13% of the ULTC-2 lesions, and 67% of the ULTC-1+PFA lesions were transmural.

CONCLUSIONS

ULTC resulted in clinically substantial lesions in healthy and infarcted ventricular myocardium. The addition of PFA to ULTC allowed for larger and more transmural lesions compared with a single ULTC ablation alone while avoiding the longer ablation times associated with 2 successive freezes.