Chik William W B, Barry Michael Anthony Tony, Thavapalachandran Sujitha, Midekin Christine, Pouliopoulos Jim, Lim Toon Wei, Sivagangabalan Gopal, Thomas Stuart P, Ross David L, McEwan Alistair L, Kovoor Pramesh, Thiagalingam Aravinda
Cardiology Department, Westmead Hospital, Sydney, Australia; Sydney Medical School, University of Sydney, Australia.
J Cardiovasc Electrophysiol. 2013 Nov;24(11):1278-86. doi: 10.1111/jce.12209. Epub 2013 Jul 11.
Radiofrequency (RF) ablation causes thermal mediated irreversible myocardial necrosis. This study aimed to (i) characterize the thermal characteristics of RF ablation lesions with high spatial resolution using a thermochromic liquid crystal (TLC) myocardial phantom; and (ii) compare the thermochromic lesions with in vivo and in vitro ablation lesions.
The myocardial phantom was constructed from a vertical sheet of TLC film, with color change between 50 °C (red) to 78 °C (black), embedded within a gel matrix, with impedance titrated to equal that of myocardium. Saline, with impedance titrated to blood values at 37 °C, was used as supernatant. A total of 51 RF ablations were performed. This comprised 17 ablations in the thermochromic gel phantom, bovine myocardial in vitro targets and ovine in vivo ablations, respectively. There was no difference in lesion dimensions between the thermochromic gel and in vivo ablations (lesion width 10.2 ± 0.2 vs 10.2 ± 2.4, P = 0.93; and depth 6.3 ± 0.1 vs 6.5 ± 1.7, P = 0.74). The spatial resolution of the thermochromic film was tested using 2 thermal point-sources that were progressively opposed and was demonstrated to be <300 μm.
High spatial resolution thermal mapping of in vitro RF lesions with spatial resolution of at least 300 μm is possible using a thermochromic liquid crystal myocardial phantom model, with a good correlation to in vivo RF ablations. This model may be useful for assessing the thermal characteristics of RF lesions created using different ablation parameters and catheter technologies.
射频（RF）消融会导致热介导的不可逆心肌坏死。本研究旨在：（i）使用热致变色液晶（TLC）心肌模型，以高空间分辨率表征RF消融损伤的热特性；（ii）将热致变色损伤与体内和体外消融损伤进行比较。
心肌模型由一片垂直的TLC膜构建而成，颜色变化范围为50°C（红色）至78°C（黑色），嵌入凝胶基质中，阻抗经滴定后与心肌相等。将37°C时阻抗经滴定至血液值的盐水用作上清液。共进行了51次RF消融。其中分别在热致变色凝胶模型、牛心肌体外靶点和绵羊体内进行了17次消融。热致变色凝胶消融与体内消融的损伤尺寸无差异（损伤宽度10.2±0.2对10.2±2.4，P = 0.93；深度6.3±0.1对6.5±1.7，P = 0.74）。使用两个逐渐相对的热点源测试了热致变色膜的空间分辨率，结果显示其小于300μm。
使用热致变色液晶心肌模型可以对体外RF损伤进行高空间分辨率的热成像，空间分辨率至少为300μm，与体内RF消融具有良好的相关性。该模型可能有助于评估使用不同消融参数和导管技术产生的RF损伤的热特性。
