title: Obesity is a major determinant of radiation dose in patients undergoing pulmonary vein isolation for atrial fibrillation.
abstract: OBJECTIVE
  This study sought to evaluate the impact of obesity on patient radiation dose during atrial fibrillation (AF) ablation procedures under fluoroscopic guidance.
  
  
  BACKGROUND
  Obesity is a risk factor for AF and its recurrence after ablation. It increases patient radiation dose during fluoroscopic imaging, but this effect has not been quantified for AF ablation procedures.
  
  
  METHODS
  Effective radiation dose and lifetime attributable cancer risk were calculated from dose-area product (DAP) measurements in 85 patients undergoing AF ablation guided by biplane low-frequency pulsed fluoroscopy (3 frames/s). Three dose calculation methods were used (Monte Carlo simulation, dose conversion coefficients, and depth-profile dose curves).
  
  
  RESULTS
  Median DAP for all patients was 119.6 Gy x cm2 (range 13.9 to 446.3 Gy x cm2) for procedures with a median duration of 4 h and 83 +/- 26 min of fluoroscopy. Body mass index was a more important determinant of DAP than total fluoroscopy time (r = 0.74 vs. 0.37, p < 0.001), with mean DAP values per hour of fluoroscopy of 58 +/- 40 Gy x cm2, 110 +/- 43 Gy x cm2, and 184 +/- 79 Gy x cm2 in normal, overweight, and obese patients, respectively. The corresponding effective radiation doses for AF ablation procedures were 15.2 +/- 7.8 mSv, 26.7 +/- 11.6 mSv, and 39.0 +/- 15.2 mSv, respectively (Monte Carlo). Use of conversion coefficients resulted in higher effective dose estimates than other methods, particularly in obese patients. Mean attributable lifetime risk of all-cancer mortality was 0.060%, 0.100%, and 0.149%, depending on weight class.
  
  
  CONCLUSIONS
  Obese patients receive more than twice the effective radiation dose of normal-weight patients during AF ablation procedures. Obesity needs to be considered in the risk-benefit ratio of AF ablation and should prompt further measures to reduce radiation exposure.
authors.affiliation: Department of Cardiology, University Hospital Gasthuisberg, University of Leuven, Leuven, Belgium. Joris.Ector@uz.kuleuven.ac.be
authors.forename: Joris
authors.initials: J
authors.lastname: Ector
authors.forename: Octavian
authors.initials: O
authors.lastname: Dragusin
authors.forename: Bert
authors.initials: B
authors.lastname: Adriaenssens
authors.forename: Wim
authors.initials: W
authors.lastname: Huybrechts
authors.forename: Rik
authors.initials: R
authors.lastname: Willems
authors.forename: Hugo
authors.initials: H
authors.lastname: Ector
authors.forename: Hein
authors.initials: H
authors.lastname: Heidbüchel
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D015992:Body Mass Index; D017115:Catheter Ablation / Q000379:methods*; D015331:Cohort Studies; D004307:Dose-Response Relationship, Radiation; D004562:Electrocardiography; D005260:Female; D005471:Fluoroscopy; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D011336:Probability; D011667:Pulmonary Veins / Q000601:surgery*; D011829:Radiation Dosage; D015641:Radiography, Interventional; D018570:Risk Assessment; D012720:Severity of Illness Index; D016019:Survival Analysis; D016896:Treatment Outcome