title: Immediate balloon deflation for prevention of persistent phrenic nerve palsy during pulmonary vein isolation by balloon cryoablation.
abstract: BACKGROUND
  Persistent phrenic nerve palsy is the most frequent complication of cryoballoon ablation for atrial fibrillation and can be disabling.
  
  
  OBJECTIVE
  To describe a technique-immediate balloon deflation (IBD)-for the prevention of persistent phrenic nerve palsy, provide data for its use, and describe in vitro simulations performed to investigate the effect of IBD on the atrium and pulmonary vein.
  
  
  METHODS
  Cryoballoon procedures for atrial fibrillation were analyzed retrospectively (n = 130). IBD was performed in patients developing phrenic nerve dysfunction (n = 22). In vitro simulations were performed by using phantoms.
  
  
  RESULTS
  No adverse events occurred, and all patients recovered normal phrenic nerve function before leaving the procedure room. No patient developed persistent phrenic nerve palsy. The mean cryoablation time to onset of phrenic nerve dysfunction was 144 ± 64 seconds. Transient phrenic nerve dysfunction was seen more frequently with the 23-mm balloon than with the 28-mm balloon (11 of 39 cases vs 11 of 81 cases; P = .036). Balloon rewarming was faster following IBD. The time to return to 0 and 20° C was shorter in the IBD group (6.7 vs 8.9 seconds; P = .007 and 16.7 vs 37.6 seconds; P<.0001). In vitro simulations confirmed that IBD caused more rapid tissue warming (time to 0°C, 14.0 ± 3.4 seconds vs 46.0 ± 8.1; P = .0001) and is unlikely to damage the atrium or pulmonary vein.
  
  
  CONCLUSIONS
  IBD results in more rapid tissue rewarming, causes no adverse events, and appears to prevent persistent phrenic nerve palsy. Simulations suggest that IBD is unlikely to damage the atrium or pulmonary vein.
authors: Royal Prince Alfred Hospital, University of Sydney, Sydney, New South Wales, Australia.
authors: Justin
authors: J
authors: Ghosh
authors: Ali
authors: A
authors: Sepahpour
authors: Kim H
authors: KH
authors: Chan
authors: Suresh
authors: S
authors: Singarayar
authors: Mark A
authors: MA
authors: McGuire
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000601:surgery*; D003452:Cryosurgery / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006325:Heart Atria / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010243:Paralysis / Q000209:etiology / Q000517:prevention & control* / Q000601:surgery; D010791:Phrenic Nerve / Q000293:injuries* / Q000601:surgery; D011183:Postoperative Complications / Q000517:prevention & control*; D011667:Pulmonary Veins / Q000601:surgery*; D012189:Retrospective Studies; D016896:Treatment Outcome