Evaluation of Ablation Catheter Technology: Comparison between Thigh Preparation Model and an In-Vivo Beating Heart

• Published in: Heart rhythm Vol. 14; no. 8; pp. 1234 - 1240
• Main Authors: Leshem, Eran, MD, MHA, Tschabrunn, Cory M., PhD, Contreras-Valdes, Fernando M., MD, Zilberman, Israel, DVM, Anter, Elad, MD
• Format: Journal Article
• Language: English
• Published: United States 01.08.2017
• Subjects: Animals; Arrhythmias, Cardiac - diagnosis; Arrhythmias, Cardiac - physiopathology; Arrhythmias, Cardiac - surgery; Cardiac Catheters; Cardiovascular; Catheter Ablation - methods; Cross-Sectional Studies; Disease Models, Animal; Electric Impedance; Equipment Design; Heart Ventricles - pathology; Heart Ventricles - physiopathology; Materials Testing; Muscle, Skeletal - physiopathology; Swine; Therapeutic Irrigation - methods; Thigh muscle; Animal models; Radiofrequency; Lesion assessment; Ablation; Ablation biophysics
• ISSN: 1547-5271; 1556-3871
• DOI: 10.1016/j.hrthm.2017.04.035

Abstract Background An in-vivo animal thigh model is the standard technique for evaluation of ablation catheter technologies, including efficacy and safety of ablation. However, the biophysics of ablation in a thigh model may not be similar to a beating heart. Objective The aim of this study was to compare efficacy and safety of ablation between a thigh preparation model and a beating heart. Methods In 7 swine, radiofrequency (RF) ablation using a 3.5mm open irrigated catheter (Thermocool Smart Touch®) was performed sequentially in a thigh muscle and in-vivo beating ventricles. Ablation was performed at low (30W for 40Ssec) and high (40W for 60Sec) energy settings and at similar contact force. Ablation lesions were scanned in high-resolution and measured using electronic calipers. Results A total of 152 RF ablation lesions were measured (86 thigh and 66 heart). At low-energy, lesion width was greater in the thigh model (12.19±1.8mm vs. 8.99±2.1mm; p<0.001) while lesion depth was similar between the thigh and heart (5.71±0.8mm vs. 5.95±1.3mm, respectively; p=0.18). The planar cross-sectional lesion area was greater in the thigh model (thigh 54.8±10.8mm2 vs. heart 43.1±16.1mm2 ; p<0.001). At high-energy setting, lesion depth, width, and area were all greater in the thigh model (thigh 91.5±16.8mm2 vs. heart 56.0±15.5mm2 ; p<0.001). The incidence of steam pop and char formation was similar between the models. Conclusion The thigh preparation model is a reasonable technique for evaluation of ablation catheter technology, however it often results in overestimation of lesion size, especially at higher energy settings.