Detailed analysis of the lesion formation using a diamond tip catheter in an ex vivo experimental model

Abstract

Background: A novel Diamond Temp™ (DT; Medtronic, Minneapolis, MN, USA) catheter has enabled performing a surface temperature-controlled ablation. The chemical vapor deposition diamond of the ablation catheter acts as a thermal radiator and is useful for effective cooling of the ablation catheter tip. However, a detailed analysis of the lesion formation with this catheter remains unknown.

Methods: DT catheters were used in an excised swine heart experimental model. A cross-sectional analysis of 60-s lesions [a combination of various energy power settings (30, 40, and 50 W), and various contact forces (CF) (10, 30, and 50 g)] and a longitudinal analysis [a combination of various powers (40 W or 50 W), various CFs (10, 30, and 50 g), and various ablation times (5 s, 10 s, 15 s, 20 s, 25 s, 30 s, and 60 s)] of the DT catheter were analyzed.

Results: The maximum lesion depth, maximum diameter, and lesion volume with a 10 g ablation were significantly lower than those with a 30 g or 50 g ablation. There were no significant differences in the lesion formation between the 30 g ablation and 50 g ablation under each radiofrequency (RF) power setting. The impedance drops with steam pops were significantly greater than those without steam pops (pop (+) vs. pop (-), 26.2 ± 6.6 Ohm vs. 18.4 ± 7.1 Ohm, p = 0.0001). A non-linear, time-dependent increase in the lesion depth and diameter was observed for all power and CF settings. Comparing the lesion depth and diameter between 40 W and 50 W under the same CF setting and same ablation time, most of the settings had no significant difference.

Conclusion: Ablation lesions created with the DT catheter were similar to other catheters. Similar ablation lesions were created with the 40 W or 50 W ablation under the same CF setting and same ablation time. Regardless of the ablation power, monitoring the general impedance during the RF application was indispensable for a safe procedure.

Keywords: Diamond temp catheter; Ex vivo experimental model; Lesion size; Radiofrequency ablation.