Copyright © 2017 International Anesthesia Research Society. Unauthorized reproduction of this article is prohibited. July 2017 • Volume 125 • Number 1 www.anesthesia-analgesia.org 1 Copyright © 2017 International Anesthesia Research Society DOI: 10.1213/ANE.0000000000002111 W orldwide, about 200 million adults undergo major noncardiac surgery annually. 1 New atrial fbrilla- tion (AF) is the most common cardiac arrhythmia after noncardiac surgery. 2 However, its pathophysiology is not well understood, with several perioperative factors likely involved, including increased sympathetic outfow, metabolic alterations (eg, hypoglycemia/hyperglycemia and electrolyte disturbances), and infammation. 3 A large prospective cohort study (4181 patients) including consecu- tive patients undergoing noncardiac surgery suggested that BACKGROUND: Despite the frequency of new clinically important atrial fbrillation (AF) after non- cardiac surgery and its increased association with the risk of stroke at 30 days, there are limited data informing their prediction, association with outcomes, and management. METHODS: We used the data from the PeriOperative ISchemic Evaluation trial to determine, in patients undergoing noncardiac surgery, the association of new clinically important AF with 30-day outcomes, and to assess management of these patients. We also aimed to derive a clinical prediction rule for new clinically important AF in this population. We defned new clinically important AF as new AF that resulted in symptoms or required treatment. We recorded an elec- trocardiogram 6 to 12 hours postoperatively and on the 1st, 2nd, and 30th days after surgery. RESULTS: A total of 211 (2.5% [8351 patients]; 95% confdence interval, 2.2%–2.9%) patients developed new clinically important AF within 30 days of randomization (8140 did not develop new AF). AF was independently associated with an increased length of hospital stay by 6.0 days (95% confdence interval, 3.5–8.5 days) and vascular complications (eg, stroke or conges- tive heart failure). The usage of an oral anticoagulant at the time of hospital discharge among patients with new AF and a CHADS 2 score of 0, 1, 2, 3, and ≥4 was 6.9%, 10.2%, 23.0%, 9.4%, and 33.3%, respectively. Two independent predictors of patients developing new clinically impor- tant AF were identifed (ie, age and surgery). The prediction rule included the following factors and assigned weights: age ≥85 years (4 points), age 75 to 84 years (3 points), age 65 to 74 years (2 points), intrathoracic surgery (3 points), major vascular surgery (2 points), and intra- abdominal surgery (1 point). The incidence of new AF based on scores of 0 to 1, 2, 3 to 4, and 5 to 6 was 0.5%, 1.0%, 3.1%, and 5.3%, respectively. CONCLUSIONS: Age and surgery are independent predictors of new clinically important AF in the perioperative setting. A minority of patients developing new clinically important AF with high CHADS 2 scores are discharged on an oral anticoagulant. There is a need to develop effective and safe interventions to prevent this outcome and to optimize the management of this event when it occurs. (Anesth Analg 2017;125:00–00) Predictors, Prognosis, and Management of New Clinically Important Atrial Fibrillation After Noncardiac Surgery: A Prospective Cohort Study Pablo Alonso-Coello, MD, PhD,* Deborah Cook, MD, MSc,†‡ Shou Chun Xu, MD,§ Alben Sigamani, MD,‖ Otavio Berwanger, MD,¶ Soori Sivakumaran, MD,# Homer Yang, MD,** Denis Xavier, MD, MSc,†† Luz Ximena Martinez, MD,‡‡ Pedro Ibarra, MD,§§ Purnima Rao-Melacini, MSc,‖‖ Janice Pogue, PhD,‖‖ Kelly Zarnke, MD, MSc,¶¶ Pilar Paniagua, MD, PhD,## Jack Ostrander, MD,*** Salim Yusuf, MBBS, PhD,†‡††† and P. J. Devereaux MD, PhD,†‡††† on behalf of the POISE Investigators From the *Biomedical Research Institute Sant Pau (IIB Sant Pau), CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain; Departments of †Medicine and Clinical Epidemiology and ‡Biostatistics, McMaster University, Hamilton, Ontario, Canada; §Hypertension League Institute, Beijing, China; ‖Department of Clinical Research, Narayana Hrudyalaya Limited, Bangalore, India; ¶Research Institute HCor (Heart Hospital- Hospital do Coracao), Sao Paulo, Brazil; #Department of Medicine, University of Alberta, Edmonton, Alberta, Canada; **Department of Anaesthesia, University of Ottawa, Ontario, Canada; ††St John’s Medical College and St John’s Research Institute, Bangalore, India; ‡‡Department of Medicine, Universidad Autónoma de Bucaramanga, Bucaramanga, Colombia; §§Department of Anaesthesia, Clinica Reina Sofa, Bogota, Colombia; ‖‖Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada; ¶¶Department of Medicine, University of Calgary, Alberta, Canada; ##Department of Anesthesiology, Hospital de la Sta Creu i Sant Pau, Barcelona, Spain; ***Department of Medicine, Grey Bruce Health Sciences, Owen Sound, Ontario, Canada; and †††Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada. Accepted for publication March 7, 2017. Funding: Funding for this study was received from the Canadian Institutes of Health Research, the National Health and Medical Research Council of the Commonwealth Government of Australia, the Instituto de Salud Carlos III (Ministerio de Sanidad y Consumo) in Spain, the British Heart Foundation, and AstraZeneca, which provided the study drug and funding for drug label- ing, packaging, and shipping, and helped support the cost of some national POISE investigator meetings. Conficts of Interest: See Disclosures at the end of the article. This report describes human research. All participating sites obtained ethi- cal approval from institution ethics review boards before recruiting patients. This report describes cohort observational clinical study. The authors state that the report includes every item in the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist for cohort obser- vational clinical studies. This manuscript was screened for plagiarism using CrossRefMe. Reprints will not be available from the authors. Address correspondence to Pablo Alonso-Coello, MD, PhD, Biomedical Research Institute Sant Pau (IIB Sant Pau), CIBER Epidemiología y Salud Pública (CIBERESP), Hospital de la Santa Creu i Sant Pau, Pavellón 18, planta baja, c/ Sant Antoni M. Claret, 167, 08025 Barcelona, Spain. Address e-mail to palonso@santpau.cat.