Mizukami Kazuya, Homma Tsuneaki, Natsui Hiroyuki, Kato Mizuki, Otsu Keisuke, Takenaka Takashi, Sato Minoru
Department of Cardiovascular Medicine National Hospital Organization Hokkaido Medical Center Sapporo Japan.
J Arrhythm. 2020 Feb 13;36(2):328-334. doi: 10.1002/joa3.12314. eCollection 2020 Apr.
Phrenic nerve injury (PNI) is one of the important complications during cryoballoon (CB) ablation. Recording diaphragmatic compound motor action potentials (CMAPs) during CB ablation can predict PNI. CMAP monitoring may be inaccurate when CMAP amplitudes are low. We examined the effect of positioning an electrocardiography (ECG) electrode at the dorsal side.
We retrospectively analyzed the cases of 197 consecutive patients who underwent CB ablation for pulmonary vein isolation (PVI) (April 2016 to December 2018) at our institution. CMAP amplitudes were monitored using two recording methods just before cryoapplication. (a) Conventional method: right-arm ECG electrode positioned 5 cm above the xiphoid on the ventral side; left-arm ECG electrode positioned along the costal margin. (b) Our original method: right-arm electrode positioned 5 cm above the xiphoid on the dorsal side; left-arm electrode positioned along the costal margin.
The CMAP amplitude during right phrenic nerve pacing was significantly higher at the dorsal side than the ventral side (0.80 ± 0.31 mV vs 0.66 ± 0.29 mV, < .01). Similarly, the CMAP amplitude during left phrenic nerve pacing was significantly higher at the dorsal side than the ventral side (0.92 ± 0.39 mV, 0.73 ± 0.37 mV, < .01). PNI occurred in six patients (3.0%); three patients experienced transient PNI, another three patients experienced persistent PNI, and none developed permanent PNI.
CMAP amplitudes were significantly high at the dorsal side compared to the ventral side. Monitoring phrenic nerve function using an ECG electrode at the dorsal side is a simple and easy procedure.
膈神经损伤（PNI）是冷冻球囊（CB）消融过程中的重要并发症之一。在CB消融期间记录膈神经复合运动动作电位（CMAP）可预测PNI。当CMAP波幅较低时，CMAP监测可能不准确。我们研究了将心电图（ECG）电极置于背侧的效果。
我们回顾性分析了在我院连续197例接受CB消融治疗肺静脉隔离（PVI）（2016年4月至2018年12月）患者的病例。在冷冻应用前，使用两种记录方法监测CMAP波幅。（a）传统方法：右臂ECG电极置于剑突上方腹侧5 cm处；左臂ECG电极沿肋缘放置。（b）我们的原始方法：右臂电极置于剑突上方背侧5 cm处；左臂电极沿肋缘放置。
右侧膈神经起搏时，背侧的CMAP波幅明显高于腹侧（0.80±0.31 mV对0.66±0.29 mV，<0.01）。同样，左侧膈神经起搏时，背侧的CMAP波幅明显高于腹侧（0.92±0.39 mV，0.73±0.37 mV，<0.01）。6例患者（3.0%）发生PNI；3例患者出现短暂性PNI，另外3例患者出现持续性PNI，无一例发生永久性PNI。
与腹侧相比，背侧的CMAP波幅明显更高。使用背侧的ECG电极监测膈神经功能是一种简单易行的方法。
