In Vivo Tissue Temperature Characteristics of Contact Force Catheter With a Mesh-Shaped Irrigation Tip: A Porcine Study.

Abstract

<h4>Background</h4>Neither the actual in vivo tissue temperatures reached with a novel contact force sensing catheter with a mesh-shaped irrigation tip (TactiFlex SE, Abbott) nor the safety profile has been elucidated.<h4>Methods</h4>In a porcine model (n = 8), thermocouples were implanted epicardially in the superior vena cava, right pulmonary vein, and esophagus close to the inferior vena cava following a right thoracotomy. After chest closure, endocardial ablation was conducted near the thermocouples under fluoroscopic guidance. We compared tissue temperatures during 50 W/13-s high-power short-duration (HPSD) and 30 W/30-s standard ablation.<h4>Results</h4>No steam pops were observed in 34 HPSD and 35 standard ablation applications. Tmax (maximum tissue temperature when the thermocouple was located ≤5 mm from the catheter tip) was modestly higher in HPSD compared to standard ablation (60.1°C ± 12.4°C vs. 57.8°C ± 12.9°C; p = 0.46). The peak tissue temperature correlated inversely with the catheter tip-to-thermocouple distance (HPSD: r = -0.40; standard: r = -0.57). Lethal temperatures (≥50°C) were reached faster with HPSD (6.5 ± 3.2 s vs. 10.3 ± 8.6 s; p = 0.04) and the distance from the catheter tip achieving a lethal tissue temperature ≥50°C (indicative of the lesion depth) was slightly shallower with HPSD (4.2 and 4.8 mm, respectively). The esophageal injury occurred superficially in both settings (0.98 ± 0.22 mm vs. 1.16 ± 0.18 mm; p = 0.29).<h4>Conclusions</h4>HPSD ablation produced a modestly higher and more rapid increase in the tissue temperature around the veno-atrial junction with a shorter catheter tip-to-thermocouple distance required to reach lethal temperatures. This data contributes to understanding effective lesion creation and collateral injury prevention with the TactiFlex catheter.