title: Phrenic nerve injury: An underrecognized and potentially preventable complication of pulmonary vein isolation using a wide-area circumferential ablation approach.
abstract: BACKGROUND
  Phrenic nerve injury (PNI) is a well-known, although uncommon, complication of pulmonary vein isolation (PVI) using radiofrequency energy. Currently, there is no consensus about how to avoid or minimize this injury. The purpose of this study was to determine how often the phrenic nerve, as identified using a high-output pacing, lies along the ablation trajectory of a wide-area circumferential lesion set. We also sought to determine if PVI can be achieved without phrenic nerve injury by modifying the ablation lesion set so as to avoid those areas where phrenic nerve capture (PNC) is observed.
  
  
  RESULTS
  We prospectively enrolled 100 consecutive patients (age 61.7 ± 9.2 years old, 75 men) who underwent RF PVI using a wide-area circumferential ablation approach. A high-output (20 mA at 2 milliseconds) endocardial pacing protocol was performed around the right pulmonary veins and the carina where a usual ablation lesion set would be made. A total of 30% of patients had PNC and required modification of ablation lines. In the group of patients with PNC, the carina was the most common site of capture (85%) followed by anterior right superior pulmonary vein (RSPV) (70%) and anterior right inferior pulmonary vein (RIPV) (30%). A total of 25% of PNC group had capture in all 3 (RSPV, RIPV, and carina) regions. There was no difference in the clinical characteristics between the groups with and without PNC. RF PVI caused no PNI in either group.
  
  
  CONCLUSIONS
  High output pacing around the right pulmonary veins and the carina reveals that the phrenic nerve lies along a wide-area circumferential ablation trajectory in 30% of patients. Modification of ablation lines to avoid these sites may prevent phrenic nerve injury during RF PVI.
authors.affiliation: Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Sang
authors.initials: S
authors.lastname: Yong Ji
authors.forename: Jane
authors.initials: J
authors.lastname: Dewire
authors.forename: Bernadette
authors.initials: B
authors.lastname: Barcelon
authors.forename: Binu
authors.initials: B
authors.lastname: Philips
authors.forename: John
authors.initials: J
authors.lastname: Catanzaro
authors.forename: Saman
authors.initials: S
authors.lastname: Nazarian
authors.forename: Alan
authors.initials: A
authors.lastname: Cheng
authors.forename: David
authors.initials: D
authors.lastname: Spragg
authors.forename: Harikrishna
authors.initials: H
authors.lastname: Tandri
authors.forename: Sandeep
authors.initials: S
authors.lastname: Bansal
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ashikaga
authors.forename: Jack
authors.initials: J
authors.lastname: Rickard
authors.forename: Aravindan
authors.initials: A
authors.lastname: Kolandaivelu
authors.forename: Sunil
authors.initials: S
authors.lastname: Sinha
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Marine
authors.forename: Hugh
authors.initials: H
authors.lastname: Calkins
authors.forename: Ronald
authors.initials: R
authors.lastname: Berger
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation / Q000009:adverse effects* / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D059348:Peripheral Nerve Injuries / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D010791:Phrenic Nerve / Q000293:injuries*; D011446:Prospective Studies; D011667:Pulmonary Veins / Q000503:physiopathology / Q000601:surgery*; D012307:Risk Factors; D016896:Treatment Outcome
keywords: atrial fibrillation; phrenic nerve capture; phrenic nerve injury; pulmonary vein isolation; radiofrequency ablation; wide-area circumferential ablation