title: Clinical characteristics of massive air embolism complicating left atrial ablation of atrial fibrillation: lessons from five cases.
abstract: OBJECTIVE
  This study aimed to elucidate the clinical characteristics of massive air embolism occurring during atrial fibrillation (AF) ablation.
  
  
  RESULTS
  Of 2976 patients undergoing AF ablation, 5 patients complicated by serious air embolism were examined. Atrial fibrillation ablation was performed with the use of three long sheaths for circular mapping and ablation catheters under conscious sedation. Two patients had air spontaneously introduced through a haemostasis valve of the long sheaths, at the end of long apnoea caused by the sedation, even though the catheters were placed within the long sheaths. The remaining three patients, all of whom also exhibited long apnoea, had air entry at the circular mapping catheter exchanges. Air accumulated in the right and left ventricles, left atrial appendage, right coronary artery, and ascending aorta. Haemodynamic collapse and hypoxaemia occurred in all and two patients, respectively, and supportive treatment and the accumulated air were aspirated. ST elevation, haemodynamic collapse, and hypoxaemia persisted for 10-35 min; however, all patients recovered completely. After we changed the sedative to one with less respiratory depressive effects and the timing of the saline flush at the circular mapping catheter exchanges, we never experienced such serious complications any further.
  
  
  CONCLUSIONS
  Serious air embolism can occur in patients with long apnoea under sedation during AF ablation with the use of long sheaths. Supportive therapy and air aspiration were effective in resolving the complication. A sedative that causes less respiratory depression and the timing of the saline flush were important for preventing air embolism.
authors.affiliation: Cardiovascular Centre, Yokosuka Kyousai Hospital, 1-16, Yonegahama-dori, Yokosuka, Kanagawa, Japan. dr.kuwahara@gmail.com
authors.forename: Taishi
authors.initials: T
authors.lastname: Kuwahara
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takahashi
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kobori
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Miyazaki
authors.forename: Asumi
authors.initials: A
authors.lastname: Takei
authors.forename: Akira
authors.initials: A
authors.lastname: Fujii
authors.forename: Shigeki
authors.initials: S
authors.lastname: Kusa
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Yagishita
authors.forename: Kenji
authors.initials: K
authors.lastname: Okubo
authors.forename: Tadashi
authors.initials: T
authors.lastname: Fujino
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nozato
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hikita
authors.forename: Akira
authors.initials: A
authors.lastname: Sato
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Aonuma
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000150:complications* / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects* / Q000379:methods*; D004618:Embolism, Air / Q000209:etiology* / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome