Miyazaki Shinsuke, Ichihara Noboru, Nakamura Hiroaki, Taniguchi Hiroshi, Hachiya Hitoshi, Araki Makoto, Takagi Takamitsu, Iwasawa Jin, Kuroi Akio, Hirao Kenzo, Iesaka Yoshito
Cardiovascular Center, Tsuchiura Kyodo Hospital, Tsuchiura, Ibaraki, Japan.
Heart Rhythm Center, Tokyo Medical and Dental University, Tokyo, Japan.
J Cardiovasc Electrophysiol. 2016 Apr;27(4):390-5. doi: 10.1111/jce.12912. Epub 2016 Feb 8.
Right phrenic nerve injury (PNI) is a major concern during superior vena cava (SVC) isolation due to the anatomical close proximity. The functional and histological severity of PNI parallels the degree of the reduction in the compound motor action potential (CMAP) amplitude. This study aimed to evaluate the feasibility of monitoring CMAPs during SVC isolation to anticipate PNI during atrial fibrillation (AF) ablation.
Thirty-nine paroxysmal AF patients were prospectively enrolled. Radiofrequency energy was delivered point-by-point for 30 seconds with 20 W until eliminating all SVC potentials after the pulmonary vein isolation. Right diaphragmatic CMAPs were obtained from modified surface electrodes by pacing from the right subclavian vein. Radiofrequency applications were applied without fluoroscopy under CMAP monitoring at sites with phrenic nerve capture by high output pacing.
Electrical SVC isolation was successfully achieved with a mean of 9.4 ± 3.3 applications in all patients. In 3 (7.5%) patients, the SVC was isolated without radiofrequency delivery at phrenic nerve capture sites. Among a total of 346 applications in the remaining 36 patients, 71 (20.5%) were delivered while monitoring CMAPs. In 1 (1.4%) application, the RF application was interrupted due to a decrease in the CMAP amplitude. However, no PNI was detected on fluoroscopy, and the decreased amplitude recovered spontaneously. The remaining 70 (98.6%) applications exhibited no significant changes in the CMAP amplitude throughout the applications (from 1.01 ± 0.47 to 0.98 ± 0.45 mV, P = 0.383).
Stable right diaphragmatic CMAPs could be obtained, and monitoring CMAPs might be useful for anticipating right PNI during SVC isolation.
由于解剖位置相邻，右膈神经损伤（PNI）是上腔静脉（SVC）隔离期间的一个主要问题。PNI的功能和组织学严重程度与复合运动动作电位（CMAP）幅度降低的程度平行。本研究旨在评估在SVC隔离期间监测CMAP以预测心房颤动（AF）消融期间PNI的可行性。
前瞻性纳入39例阵发性AF患者。在肺静脉隔离后，以20W逐点施加射频能量30秒，直至消除所有SVC电位。通过从右锁骨下静脉起搏，从改良的表面电极获取右膈CMAP。在CMAP监测下，在高输出起搏捕获膈神经的部位，无需透视即可应用射频。
所有患者平均进行9.4±3.3次应用成功实现了电SVC隔离。3例（7.5%）患者在膈神经捕获部位未进行射频传递即实现了SVC隔离。在其余36例患者的总共346次应用中，71次（20.5%）是在监测CMAP时进行的。在1次（1.4%）应用中，由于CMAP幅度降低，射频应用中断。然而，透视未检测到PNI，幅度降低自发恢复。其余70次（98.6%）应用在整个应用过程中CMAP幅度无显著变化（从1.01±0.47mV降至0.98±0.45mV，P=0.383）。
可以获得稳定的右膈CMAP，监测CMAP可能有助于预测SVC隔离期间的右PNI。
