Nazer Babak, Salgaonkar Vasant, Diederich Chris J, Jones Peter D, Duggirala Srikant, Tanaka Yasuaki, Ng Bennett, Sievers Richard, Gerstenfeld Edward P
From the Electrophysiology Section, Division of Cardiology, Department of Medicine (B.N., S.D., Y.T., R.S., E.P.G.), and Thermal Therapy Research Group, Department of Radiation Oncology (V.S., C.J.D., P.D.J., B.N.), University of California San Francisco.
Circ Arrhythm Electrophysiol. 2015 Dec;8(6):1491-7. doi: 10.1161/CIRCEP.115.003547. Epub 2015 Nov 6.
Epicardial radiofrequency catheter ablation of ventricular tachycardia remains challenging because of the presence of deep myocardial scar and adjacent cardiac structures, such as the coronary arteries, phrenic nerve, and epicardial fat that limit delivery of radiofrequency energy. High-intensity ultrasound (HIU) is an acoustic energy source able to deliver deep lesions through fat, while sparing superficial structures. We developed and tested an epicardial HIU ablation catheter in a closed chest, in vivo swine model.
The HIU catheter is an internally cooled, 14-French, side-facing catheter, integrated with A-mode ultrasound guidance. Swine underwent percutaneous subxyphoid epicardial access and ablation with HIU (n=10 swine) at 15, 20, and 30 W. Compared with irrigated radiofrequency lesions in control swine (n = 5), HIU demonstrated increased lesion depth (HIU 11.6±3.2 mm versus radiofrequency 4.7±1.6 mm; mean±SD) and epicardial sparing (HIU 2.9±2.1 mm versus radiofrequency 0.1±0.2 mm) at all HIU powers, and increased lesion volume at HIU 20 and 30 W (P<0.0001 for all comparisons). HIU ablation over coronary arteries and surrounding epicardial fat resulted in deep lesions with normal angiographic flow. Histological disruption of coronary adventitia, but not media or intima, was noted in 44% of lesions.
Compared with radiofrequency, HIU ablation in vivo demonstrates significantly deeper and larger lesions with greater epicardial sparing in a dose-dependent manner. Further development of this catheter may lead to a promising alternative to epicardial radiofrequency ablation.
由于存在深层心肌瘢痕以及诸如冠状动脉、膈神经和心外膜脂肪等相邻心脏结构限制了射频能量的传递，心外膜射频导管消融室性心动过速仍然具有挑战性。高强度超声（HIU）是一种能够通过脂肪传递深部损伤同时保护浅表结构的声能来源。我们在封闭胸腔的体内猪模型中研发并测试了一种心外膜HIU消融导管。
HIU导管是一种内部冷却的14法式侧面开口导管，集成了A型超声引导。猪经皮剑突下心外膜穿刺并接受HIU消融（n = 10头猪），功率分别为15、20和30瓦。与对照猪（n = 5）的灌注射频损伤相比，在所有HIU功率下，HIU均显示出损伤深度增加（HIU为11.6±3.2毫米，而射频为4.7±1.6毫米；均值±标准差）以及心外膜保留更好（HIU为2.9±2.1毫米，而射频为0.1±0.2毫米），并且在HIU 20和30瓦时损伤体积增加（所有比较P<0.0001）。在冠状动脉及其周围心外膜脂肪上进行HIU消融导致深部损伤且血管造影血流正常。在44%的损伤中观察到冠状动脉外膜的组织学破坏，但中膜或内膜未受影响。
与射频相比，体内HIU消融显示出明显更深、更大的损伤，且以剂量依赖方式更好地保留心外膜。该导管的进一步研发可能会成为心外膜射频消融的一种有前景的替代方法。
