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Impact of atrial fibrillation on in-hospital outcomes among hospitalizations for cardiac surgery: an analysis of the National Inpatient Sample
  1. Kanishk Agnihotri1,
  2. Paris Charilaou2,
  3. Dinesh Voruganti3,
  4. Kulothungan Gunasekaran4,
  5. Jawahar Mehta3,
  6. Hakan Paydak3,
  7. Alexandros Briasoulis5
  1. 1 Electrophysiology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
  2. 2 Division of Gastroenterology and Hepatology, Saint Peter's University Hospital, New Brunswick, New Jersey, USA
  3. 3 Division of Cardiology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
  4. 4 Yuma Regional Medical Center, Yuma, Arizona, USA
  5. 5 Division of Cardiology, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
  1. Correspondence to Dr Kulothungan Gunasekaran, Yuma Regional Medical Center, Yuma, Arizona, USA; stankuloth{at}


The short-term impact of atrial fibrillation (AF) on cardiac surgery hospitalizations has been previously reported in cohorts of various sizes, but results have been variable. Using the 2005–2014 National Inpatient Sample, we identified all adult hospitalizations for cardiac surgery using the International Classification of Diseases, Ninth Revision, Clinical Modification as any procedure code and AF as any diagnosis code. We estimated the impact of AF on inpatient mortality, length of stay (LOS), and cost of hospitalization using survey-weighted, multivariable logistic, accelerated failure-time log-normal, and log-transformed linear regressions, respectively. Additionally, we exact-matched AF to non-AF hospitalizations on various confounders for the same outcomes. A total of 1,269,414 hospitalizations were noted for cardiac surgery during the study period. Coexistent AF was found in 44.9% of these hospitalizations. Overall mean age was 65.6 years, 40.9% were female, mean LOS was 11.6 days, and inpatient mortality was 4.5%. Stroke rate was lower in AF hospitalizations (1.8% vs 2.1%, p<0.001). Mortality was lower in the AF (3.9%) versus the non-AF (5%) group (exact-matched OR or emOR=0.48, 95% CI 0.29 to 0.80, p<0.001; 987 matched pairs, n=2423), with similar results after procedural stratification: isolated valve replacement/repair (emOR=0.38, p<0.001), isolated coronary artery bypass graft (CABG) (emOR=0.33, p<0.001), and CABG with valve replacement/repair (emOR=0.55, p<0.001). A 12% increase was seen in LOS in the AF subgroup (exact-matched time ratio=1.12, 95% CI 1.10 to 1.14, p<0.001) among hospitalizations which underwent valve replacement/repair with or without CABG. Hospitalizations for cardiac surgery which had coexistent AF were found to have lower inpatient mortality risk and stroke prevalence but higher LOS and hospitalization costs compared with hospitalizations without AF.

  • atrial fibrillation
  • arrhythmias
  • cardiac
  • heart valve diseases

Data availability statement

Data are available in a public, open access repository. Data were obtained from the National Inpatient Sample.

Statistics from

Data availability statement

Data are available in a public, open access repository. Data were obtained from the National Inpatient Sample.

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  • Contributors KA, PC, DV, KG, JM, HP, and AB contributed individually and as a group to the writing of this research with regard to the planning, conduct, reporting, conception and design, acquisition of data, or analysis and interpretation of data. DV is responsible for the overall content as the guarantor.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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