title: Imaging before cryoablation of atrial fibrillation: is phrenic nerve palsy predictable?
abstract: OBJECTIVE
  Multidetector computerized tomography (MDCT) with improved temporal and spatial resolution is one of the most commonly used non-invasive tests for evaluation of pulmonary veins (PVs) and adjacent structures before cryoablation of atrial fibrillation (AF). Identification of spatial neighbouring of phrenic nerves is important to decrease likelihood of phrenic nerve palsy (PNP). The purpose of our study is to clarify the course of right phrenic nerve, its relations to PVs using 64-slice MDCT, and effect on occurrence of PNP.
  
  
  RESULTS
  A total of 162 patients underwent MDCT with 3D reconstruction of left atrium prior to cryoablation for AF. The location of the right pericardiophrenic artery (RPA) was identified on axial images and artery distance to the right upper PV (RUPV) ostium was measured in 3D image. Right pericardiophrenic artery was detectable in 145 of 162 (89.5%) patients (52.4% male, age 54.5 ± 10.1 years, and 80.7% paroxysmal AF). Acute procedural success rate was 96.2%. Mean procedural and fluoroscopy times were 74.4 ± 6.2 and 15.7 ± 4.3 min. Transient right PNP was developed in four (2.75%) patients. RUPV ostium to RPA distance was lower in patients with PNP (P = 0.033). In multivariate regression analysis, only RUPV ostium to RPA distance (odds ratio: 2.95; 95% confidence interval: 1.76-4.66, P = 0.001) was the independent predictor of PNP occurrence during cryoablation.
  
  
  CONCLUSIONS
  Our results revealed that pre-ablation cardiac imaging with 64-slice MDCT adequately detected RPA bordering the phrenic nerve, which was an important determinant of PNP development during cryoballoon-based AF ablation.
authors.affiliation: Department of Cardiology, Hacettepe University Faculty of Medicine, Ankara 06100, Turkey.
authors.forename: Uğur
authors.initials: U
authors.lastname: Canpolat
authors.forename: Kudret
authors.initials: K
authors.lastname: Aytemir
authors.forename: Mustafa
authors.initials: M
authors.lastname: Hızal
authors.forename: Tuncay
authors.initials: T
authors.lastname: Hazırolan
authors.forename: Hikmet
authors.initials: H
authors.lastname: Yorgun
authors.forename: Levent
authors.initials: L
authors.lastname: Sahiner
authors.forename: Ergun Barış
authors.initials: EB
authors.lastname: Kaya
authors.forename: Ali
authors.initials: A
authors.lastname: Oto
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D016009:Chi-Square Distribution; D003452:Cryosurgery / Q000009:adverse effects*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D015999:Multivariate Analysis; D016017:Odds Ratio; D010243:Paralysis / Q000209:etiology* / Q000503:physiopathology; D059348:Peripheral Nerve Injuries / Q000209:etiology* / Q000503:physiopathology; D010791:Phrenic Nerve / Q000293:injuries* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011300:Preoperative Care; D011667:Pulmonary Veins / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome
keywords: Atrial fibrillation; Computerized tomography; Cryoballoon; Phrenic nerve palsy