Experimental Study Of Cardiac Ultrasound Ablation In Canine Heart

Background: Ultrasound is considered as an alternative energy for cardiac arrhythmias ablation due to its good penetration through tissues. This study was designed to observe the effects of acoustic power, duration, repetitive ablations, tissue-transducer interface temperature and different sites on the ultrasound ablation in vitro. We also compared the histological and electrical damages of ultrasound ablation and evaluated the feasibility of using ultrasound energy for chronic myocardial infarction scar ablation in vivo. Methods: in vitro: 1,Ultrasound ablation were conducted with different acoustic powers (3.0W/cm2 ~ 9.67W/cm2), durations (20sec ~ 90sec) and repetitive times(l~4) to observe the relationships between lesion size and those physical factors; 2, Lesion volume and depth were compared between right and left ventricular muscles to observe the effect of myocardial architecture on ultrasound ablation; 3, Two different types of transducers with(model A) and without(model B) direct tissue contact were used to observe the ablative effects of tissue-transducer contact condition. In vivo: 1, Ultrasound ablation was applied on the epicardium in vivo to compare the histological and electrophysiological damages in ten canines in vivo; 2, After chronic myocardial infarction, ultrasound ablation was applied on the scar regions in 5 canines.Results: in vitro: 1,While the acoustic power increased from 3.0W/cm~2 to 9.67w/cm~2, the lesion depth and volume increased from 1.96 ± 0.18mm and 64 ± 11.40mm~3 to 6.31±0.58mm and 538.51 ±82.63mm~3,...