title: Detection of atrial fibrillation using contactless facial video monitoring.
abstract: BACKGROUND
  It is estimated that 33.5 million people in the world have developed atrial fibrillation (AF), and an estimated 30% of patients with AF are unaware of their diagnosis (silent AF).
  
  
  OBJECTIVE
  The purpose of this study was to test a new technology for contactless detection of AF based on facial video recordings.
  
  
  METHODS
  The proposed technique uses a camera to record an individual's face and extract the subtle beat-to-beat variations of skin color reflecting the cardiac pulsatile signal. In a group of adults referred for electrical cardioversion, we recorded the ECG and the video of the subjects' face before and after electrical cardioversion. We extracted the beat-to-beat pulse rates expressed as pulses per minute (ppm) from the videoplethysmographic (VPG) signal acquired using a standard web camera. We introduce a novel quantifier of pulse variability called the pulse harmonic strength (PHS) and report its ability to detect the presence of AF.
  
  
  RESULTS
  Eleven subjects (8 male; age 65 ± 6 years) were included in the study. The VPG and ECG-based rates were statistically different between the AF and sinus rhythm periods: 72 ± 9 ppm vs 57 ± 7 ppm (P < .0001) for VPG and 80 ± 17 bpm vs 56 ± 7 bpm (P < .0001) for ECG signals. Among the 407 epochs of 15 seconds of synchronized ECG and VPG signals, PHS was associated with a 20% detection error rate, and the error rates of the automatic ECG-based measurements ranged between 17% and 29%.
  
  
  CONCLUSIONS
  Our preliminary results support the concept that contactless video-based monitoring of the human face for detection of abnormal pulse variability due to AF is feasible.
authors.affiliation: Heart Research Follow-up Program, Cardiology Department, University of Rochester Medical Center, University of Rochester, New-York. Electronic address: Jean-Philippe.Couderc@heart.rochester.edu.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Couderc
authors.affiliation: Palo Alto Research Center-A Xerox Company, Webster, New York.
authors.forename: Survi
authors.initials: S
authors.lastname: Kyal
authors.affiliation: Palo Alto Research Center-A Xerox Company, Webster, New York.
authors.forename: Lalit K
authors.initials: LK
authors.lastname: Mestha
authors.affiliation: Palo Alto Research Center-A Xerox Company, Webster, New York.
authors.forename: Beilei
authors.initials: B
authors.lastname: Xu
authors.affiliation: Department of Biostatistics and Computational Biology, University of Rochester Medical Center, Rochester, New York.
authors.forename: Derick R
authors.initials: DR
authors.lastname: Peterson
authors.affiliation: Heart Research Follow-up Program, Cardiology Department, University of Rochester Medical Center, University of Rochester, New-York.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Xia
authors.affiliation: Heart Research Follow-up Program, Cardiology Department, University of Rochester Medical Center, University of Rochester, New-York.
authors.forename: Burr
authors.initials: B
authors.lastname: Hall
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000150:complications / Q000175:diagnosis* / Q000628:therapy; D004554:Electric Countershock; D004562:Electrocardiography; D005149:Facial Expression; D005240:Feasibility Studies; D005260:Female; D005483:Flushing / Q000175:diagnosis / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017156:Photoplethysmography / Q000379:methods*; D012372:ROC Curve; D012880:Skin Pigmentation; D014741:Video Recording
keywords: Atrial fibrillation; Electrocardiogram; Heart rate variability; Monitoring; Prevention