Department of Medical Ultrasonics, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510080, Guangdong, China.
Department of Medical Ultrasonics, Division of Interventional Ultrasound, Institute of Diagnostic and Interventional Ultrasound, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510080, Guangdong, China.
BMC Cardiovasc Disord. 2020 Oct 20;20(1):454. doi: 10.1186/s12872-020-01735-3.
To explore the lesion outline and thermal field distribution of radiofrequency ablation (RFA) and laser ablation (LA) in myocardial ablation in vitro.
Twenty-four fresh porcine hearts were ablated with RFA or LA in vitro. The radiofrequency electrode or laser fiber and two parallel thermocouple probes were inserted into the myocardium under ultrasound guidance. The output power for RFA was 20 W/s and for LA was 5 W/s, and the total thermal energies were 1200 J, 2400 J, 3600 J, and 4800 J. The range of ablation lesions was measured, and temperature data were recorded simultaneously.
All coagulation zones were ellipsoidal with clear boundaries. The center of LA was carbonized more obviously than that of RFA. With the accumulation of thermal energy and the extended time, all the ablation lesions induced by both RFA and LA were enlarged. By comparing the increase in thermal energy between the two groups, both the short-axis diameter and the volume change showed significant differences between the 1200 J and 3600 J groups and between the 2400 J and 4800 J groups (all P < 0.05). Both the short-axis diameter and the volume of the coagulation necrosis zone formed by LA were always larger than those of RFA at the same accumulated thermal energy. The temperatures of the two thermocouple probes increased with each energy increment. At the same accumulated energy, the temperature of LA was much higher than that of RFA at the same point. The initial temperature increase at 0.5 cm of LA was rapid. The temperature reached 43 °C and the accumulated energy reached 1200 J after approximately 4 min. After that the temperature increased at a slower rate to 70 C. For the RFA at the point of 0.5 cm, the initial temperature increased rapidly to 30 °C with the same accumulated energy of 1200 J after only 1 min. In the range of 4800 J of accumulated thermal energy, only the temperature of LA at the point of 0.5 cm exceeded 60 °C when the energy reached approximately 3000 J.
Both RFA and LA were shown to be reliable methods for myocardial ablation. The lesion outline and thermal field distribution of RFA and LA should be considered when performing thermal ablation in the intramyocardial septum during hypertrophic obstructive cardiomyopathy.
探讨射频消融（RFA）和激光消融（LA）在心肌消融中的病灶轮廓和热场分布。
在体外对 24 只新鲜猪心进行 RFA 或 LA 消融。在超声引导下将射频电极或激光纤维和两个平行热电偶探头插入心肌。RFA 的输出功率为 20 W/s，LA 的输出功率为 5 W/s，总热能分别为 1200 J、2400 J、3600 J 和 4800 J。测量消融病灶范围，同时记录温度数据。
所有凝固区均呈椭圆形，边界清晰。LA 的中心碳化比 RFA 更明显。随着热能的积累和时间的延长，RFA 和 LA 引起的所有消融病灶均增大。通过比较两组之间热能的增加，无论是短轴直径还是体积变化，在 1200 J 和 3600 J 组以及 2400 J 和 4800 J 组之间均有显著差异（均 P<0.05）。在相同的累积热能下，LA 形成的凝固坏死区的短轴直径和体积始终大于 RFA。两个热电偶探头的温度随每个能量增量而升高。在相同的累积能量下，同一部位的 LA 温度远高于 RFA。LA 初始升温在 0.5 cm 处迅速，约 4 分钟后达到 43°C，累积能量达到 1200 J。之后，温度以较慢的速度升高至 70°C。对于 RFA 在 0.5 cm 处的点，相同的累积能量为 1200 J，仅 1 分钟后初始温度迅速升高至 30°C。在累积热能 4800 J 的范围内，只有当能量达到约 3000 J 时，LA 在 0.5 cm 处的温度才超过 60°C。
RFA 和 LA 均为可靠的心肌消融方法。在肥厚型梗阻性心肌病行心肌间隔内热消融时，应考虑 RFA 和 LA 的病灶轮廓和热场分布。
