title: Recordings of diaphragmatic electromyograms during cryoballoon ablation for atrial fibrillation accurately predict phrenic nerve injury.
abstract: BACKGROUND
  Cryoballoon ablation has been associated with a significant incidence of phrenic nerve injury (PNI).
  
  
  OBJECTIVE
  The purpose of this study was to evaluate whether recordings of diaphragmatic compound motor action potentials (CMAP) on a modified lead I during cryoballoon ablation can predict PNI.
  
  
  METHODS
  Cryoballoon ablation was performed in 109 patients with atrial fibrillation (AF). During ablation of the right-sided pulmonary veins, the phrenic nerve was paced from the superior vena cava. The right and left arm electrodes from a 12-lead ECG were positioned 5 cm above the xiphoid process and 16 cm along the right costal margin. The amplitude of CMAP was recorded on lead I during ablation.
  
  
  RESULTS
  Cryoballoon was applied 424 times in 211 right-sided veins. PNI occurred in 7 (6.4%) patients. The average CMAP amplitude did not significantly change in patients without PNI from the initial average CMAP amplitude of 0.34 ± 0.18 mV to 0.32 ± 0.17 mV (P = .58). In patients who developed PNI, there was a significant decrease in the initial average CMAP amplitude during the ablation from 0.33 ± 0.14 mV to 0.09 ± 0.05 mV (P <.001). The maximal percent change in the average CMAP amplitude in patients with PNI was higher (70% ± 10%) than in patients without PNI (7.6% ± 7%; P <.001). In any patient without PNI, the CMAP amplitude did not decrease more than 35% from baseline.
  
  
  CONCLUSIONS
  Recording of CMAP amplitude on a modified lead I is reliable and could be early and sensitive method for predicting PNI in patients undergoing cryoballoon ablation for AF.
authors.affiliation: Electrophysiology Department, Staten Island University Hospital, Staten Island, New York.
authors.forename: Mayur
authors.initials: M
authors.lastname: Lakhani
authors.affiliation: Electrophysiology Department, Staten Island University Hospital, Staten Island, New York.
authors.forename: Faisul
authors.initials: F
authors.lastname: Saiful
authors.affiliation: Electrophysiology Department, Staten Island University Hospital, Staten Island, New York.
authors.forename: Valay
authors.initials: V
authors.lastname: Parikh
authors.affiliation: Electrophysiology Department, Staten Island University Hospital, Staten Island, New York.
authors.forename: Nikhil
authors.initials: N
authors.lastname: Goyal
authors.affiliation: Electrophysiology Department, Staten Island University Hospital, Staten Island, New York.
authors.forename: Soad
authors.initials: S
authors.lastname: Bekheit
authors.affiliation: Electrophysiology Department, Staten Island University Hospital, Staten Island, New York. Electronic address: Marcin212@gmail.com.
authors.forename: Marcin
authors.initials: M
authors.lastname: Kowalski
mesh_terms: D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D021721:Balloon Occlusion / Q000379:methods*; D015897:Comorbidity; D003452:Cryosurgery / Q000379:methods*; D003964:Diaphragm / Q000503:physiopathology*; D004452:Echocardiography; D004562:Electrocardiography; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010791:Phrenic Nerve / Q000293:injuries*; D011237:Predictive Value of Tests; D012307:Risk Factors; D016896:Treatment Outcome
keywords: Atrial fibrillation; Cryoablation; Phrenic nerve injury