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Prospective Evaluation of Electromyography‐Guided Phrenic Nerve Monitoring During Superior Vena Cava Isolation to Anticipate Phrenic Nerve Injury
Author(s) -
MIYAZAKI SHINSUKE,
ICHIHARA NOBORU,
NAKAMURA HIROAKI,
TANIGUCHI HIROSHI,
HACHIYA HITOSHI,
ARAKI MAKOTO,
TAKAGI TAKAMITSU,
IWASAWA JIN,
KUROI AKIO,
HIRAO KENZO,
IESAKA YOSHITO
Publication year - 2016
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/jce.12912
Subject(s) - medicine , phrenic nerve , electromyography , superior vena cava , anesthesia , nerve injury , surgery , physical medicine and rehabilitation , respiratory system
Right Diaphragmatic CMAP During SVC Isolation Background 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. Methods 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. Results 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). Conclusions Stable right diaphragmatic CMAPs could be obtained, and monitoring CMAPs might be useful for anticipating right PNI during SVC isolation.