title: Atrial premature beats predict atrial fibrillation in cryptogenic stroke: results from the EMBRACE trial.
abstract: OBJECTIVE
  Many ischemic strokes or transient ischemic attacks are labeled cryptogenic but may have undetected atrial fibrillation (AF). We sought to identify those most likely to have subclinical AF.
  
  
  METHODS
  We prospectively studied patients with cryptogenic stroke or transient ischemic attack aged ≥55 years in sinus rhythm, without known AF, enrolled in the intervention arm of the 30 Day Event Monitoring Belt for Recording Atrial Fibrillation After a Cerebral Ischemic Event (EMBRACE) trial. Participants underwent baseline 24-hour Holter ECG poststroke; if AF was not detected, they were randomly assigned to 30-day ECG monitoring with an AF auto-detect external loop recorder. Multivariable logistic regression assessed the association between baseline variables (Holter-detected atrial premature beats [APBs], runs of atrial tachycardia, age, and left atrial enlargement) and subsequent AF detection.
  
  
  RESULTS
  Among 237 participants, the median baseline Holter APB count/24 h was 629 (interquartile range, 142-1973) among those who subsequently had AF detected versus 45 (interquartile range, 14-250) in those without AF (P<0.001). APB count was the only significant predictor of AF detection by 30-day ECG (P<0.0001), and at 90 days (P=0.0017) and 2 years (P=0.0027). Compared with the 16% overall 90-day AF detection rate, the probability of AF increased from <9% among patients with <100 APBs/24 h to 9% to 24% in those with 100 to 499 APBs/24 h, 25% to 37% with 500 to 999 APBs/24 h, 37% to 40% with 1000 to 1499 APBs/24 h, and 40% beyond 1500 APBs/24 h.
  
  
  CONCLUSIONS
  Among older cryptogenic stroke or transient ischemic attack patients, the number of APBs on a routine 24-hour Holter ECG was a strong dose-dependent independent predictor of prevalent subclinical AF. Those with frequent APBs have a high probability of AF and represent ideal candidates for prolonged ECG monitoring for AF detection.
  
  
  BACKGROUND
  URL: http://www.clinicaltrials.gov. Unique identifier: NCT00846924.
authors.affiliation: From the Division of Neurology (D.J.G.), Department of Medicine (D.J.G., P.D., M.S., M.M.), and Dalla Lana School of Public Health (K.E.T.), University of Toronto, Toronto, Ontario, Canada; University of Toronto Stroke Program, Toronto, Ontario, Canada (D.J.G.); Division of Neurology, Department of Medicine, and the Hurvitz Brain Sciences Program, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, Ontario, Canada (D.J.G.); Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Toronto, Ontario, Canada (D.J.G.); Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (M.M., V.P., K.E.T.); and Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada (J.S.H.). david.gladstone@sunnybrook.ca.
authors.forename: David J
authors.initials: DJ
authors.lastname: Gladstone
authors.affiliation: From the Division of Neurology (D.J.G.), Department of Medicine (D.J.G., P.D., M.S., M.M.), and Dalla Lana School of Public Health (K.E.T.), University of Toronto, Toronto, Ontario, Canada; University of Toronto Stroke Program, Toronto, Ontario, Canada (D.J.G.); Division of Neurology, Department of Medicine, and the Hurvitz Brain Sciences Program, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, Ontario, Canada (D.J.G.); Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Toronto, Ontario, Canada (D.J.G.); Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (M.M., V.P., K.E.T.); and Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada (J.S.H.).
authors.forename: Paul
authors.initials: P
authors.lastname: Dorian
authors.affiliation: From the Division of Neurology (D.J.G.), Department of Medicine (D.J.G., P.D., M.S., M.M.), and Dalla Lana School of Public Health (K.E.T.), University of Toronto, Toronto, Ontario, Canada; University of Toronto Stroke Program, Toronto, Ontario, Canada (D.J.G.); Division of Neurology, Department of Medicine, and the Hurvitz Brain Sciences Program, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, Ontario, Canada (D.J.G.); Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Toronto, Ontario, Canada (D.J.G.); Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (M.M., V.P., K.E.T.); and Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada (J.S.H.).
authors.forename: Melanie
authors.initials: M
authors.lastname: Spring
authors.affiliation: From the Division of Neurology (D.J.G.), Department of Medicine (D.J.G., P.D., M.S., M.M.), and Dalla Lana School of Public Health (K.E.T.), University of Toronto, Toronto, Ontario, Canada; University of Toronto Stroke Program, Toronto, Ontario, Canada (D.J.G.); Division of Neurology, Department of Medicine, and the Hurvitz Brain Sciences Program, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, Ontario, Canada (D.J.G.); Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Toronto, Ontario, Canada (D.J.G.); Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (M.M., V.P., K.E.T.); and Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada (J.S.H.).
authors.forename: Val
authors.initials: V
authors.lastname: Panzov
authors.affiliation: From the Division of Neurology (D.J.G.), Department of Medicine (D.J.G., P.D., M.S., M.M.), and Dalla Lana School of Public Health (K.E.T.), University of Toronto, Toronto, Ontario, Canada; University of Toronto Stroke Program, Toronto, Ontario, Canada (D.J.G.); Division of Neurology, Department of Medicine, and the Hurvitz Brain Sciences Program, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, Ontario, Canada (D.J.G.); Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Toronto, Ontario, Canada (D.J.G.); Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (M.M., V.P., K.E.T.); and Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada (J.S.H.).
authors.forename: Muhammad
authors.initials: M
authors.lastname: Mamdani
authors.affiliation: From the Division of Neurology (D.J.G.), Department of Medicine (D.J.G., P.D., M.S., M.M.), and Dalla Lana School of Public Health (K.E.T.), University of Toronto, Toronto, Ontario, Canada; University of Toronto Stroke Program, Toronto, Ontario, Canada (D.J.G.); Division of Neurology, Department of Medicine, and the Hurvitz Brain Sciences Program, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, Ontario, Canada (D.J.G.); Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Toronto, Ontario, Canada (D.J.G.); Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (M.M., V.P., K.E.T.); and Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada (J.S.H.).
authors.forename: Jeff S
authors.initials: JS
authors.lastname: Healey
authors.affiliation: From the Division of Neurology (D.J.G.), Department of Medicine (D.J.G., P.D., M.S., M.M.), and Dalla Lana School of Public Health (K.E.T.), University of Toronto, Toronto, Ontario, Canada; University of Toronto Stroke Program, Toronto, Ontario, Canada (D.J.G.); Division of Neurology, Department of Medicine, and the Hurvitz Brain Sciences Program, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, Ontario, Canada (D.J.G.); Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Toronto, Ontario, Canada (D.J.G.); Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Ontario, Canada (M.M., V.P., K.E.T.); and Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada (J.S.H.).
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Thorpe
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000150:complications* / Q000175:diagnosis*; D018880:Atrial Premature Complexes / Q000175:diagnosis*; D015716:Electrocardiography, Ambulatory; D005260:Female; D006801:Humans; D002546:Ischemic Attack, Transient / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D020521:Stroke / Q000209:etiology*
keywords: atrial fibrillation; atrial premature complexes; cryptogenic stroke; electrocardiography; projections and predictions; risk