Dual cryo-radiofrequency ablation enhances lesion depth in beating human left ventricular preparations

Thermally-mediated ablation has utilized various energy sources, including cryothermal, radiofrequency (RF), microwave, laser, and high-frequency ultrasound with the goal of creating lesions to terminate focal sources or block reentrant wavefronts. RF- and cryo-ablation (CR) cause cell death through different mechanisms, and leave behind tissue with altered thermal-electric properties. We aimed to assess the effect of sequential RF and CR combinations on lesion size. Left ventricular (LV) wedge preparations (n=17) were dissected from ten donated human hearts and four epicardial ablation protocols were compared: 1) RF-RF (n=7); 2) CR-CR (n=7); 3) RF-CR (n=7); and 4) CR-RF (n=7). Preparations were continuously paced and perfused with oxygenated Tyrode solution. Ablated tissue was perfused for 3 hours, sectioned, and stained with 2,3,5-triphenyltetrazolium chloride to delineate necrosis. The effect of initial thermal-electric tissue properties on lesion depth during RF application was determined using a finite element method (FEM). CR-RF generated the deepest lesion (p