From the Electrophysiology Service, Montreal Heart Institute, and the Department of Medicine, Université de Montréal, Montreal, Canada.
Circ Arrhythm Electrophysiol. 2014 Aug;7(4):605-11. doi: 10.1161/CIRCEP.113.001238. Epub 2014 Jul 13.
Phrenic nerve palsy remains the most frequent complication associated with cryoballoon-based pulmonary vein (PV) isolation. We sought to characterize our experience using a novel monitoring technique for the prevention of phrenic nerve palsy.
Two hundred consecutive cryoballoon-based PV isolation procedures between October 2010 and October 2013 were studied. In addition to standard abdominal palpation during right phrenic nerve pacing from the superior vena cava, all patients underwent diaphragmatic electromyographic monitoring using surface electrodes. Cryoablation was terminated on any perceived reduction in diaphragmatic motion or a 30% decrease in the compound motor action potential (CMAP). During right-sided ablation, a ≥30% reduction in CMAP amplitude occurred in 49 patients (24.5%). Diaphragmatic motion decreased in 30 of 49 patients and was preceded by a 30% reduction in CMAP amplitude in all. In 82% of cases, this reduction in CMAP amplitude occurred during right superior PV isolation. The baseline CMAP amplitude was 946.5±609.2 mV and decreased by 13.8±13.8% at the end of application. This decrease was more marked in the 33 PVs with a reduction in diaphragmatic motion than in those without (40.9±15.3% versus 11.3±10.5%; P<0.001). In 3 cases, phrenic nerve palsy persisted beyond the end of the procedure, with all cases recovering within 6 months. Despite the shortened application all veins were isolated. At repeat procedure the right-sided PVs reconnected less frequently than the left-sided PVs in those with phrenic nerve palsy.
Electromyographic phrenic nerve monitoring using the surface CMAP is reliable, easy to perform, and offers an early warning to impending phrenic nerve injury.
膈神经麻痹仍然是与冷冻球囊肺静脉（PV）隔离相关的最常见并发症。我们试图通过一种新的监测技术来预防膈神经麻痹，从而描述我们的经验。
2010 年 10 月至 2013 年 10 月，连续进行了 200 例冷冻球囊肺静脉隔离术。除了在右侧膈神经起搏时从上腔静脉进行标准的腹部触诊外，所有患者均使用表面电极进行膈神经肌电图监测。一旦发现膈运动减少或复合运动动作电位（CMAP）减少 30%，即终止冷冻消融。在右侧消融过程中，49 例患者（24.5%）的 CMAP 幅度减少≥30%。30 例患者的膈运动减少，所有患者的膈运动减少均先于 CMAP 幅度减少 30%。在 82%的病例中，这种 CMAP 幅度的减少发生在右侧上肺静脉隔离过程中。基础 CMAP 幅度为 946.5±609.2 mV，应用结束时降低 13.8±13.8%。膈运动减少的 33 个 PV 中，CMAP 幅度降低更为明显（40.9±15.3%比 11.3±10.5%；P<0.001）。3 例患者在手术结束后膈神经麻痹持续存在，所有患者均在 6 个月内恢复。尽管应用时间缩短，所有静脉均被隔离。在重复手术中，有膈神经麻痹的患者中右侧 PV 再连接的频率低于左侧 PV。
使用表面 CMAP 的肌电图膈神经监测可靠、易于操作，并能提供即将发生膈神经损伤的早期预警。
