title: Diagnostic Performance of a Smartphone-Based Photoplethysmographic Application for Atrial Fibrillation Screening in a Primary Care Setting.
abstract: Diagnosing atrial fibrillation (AF) before ischemic stroke occurs is a priority for stroke prevention in AF. Smartphone camera-based photoplethysmographic (PPG) pulse waveform measurement discriminates between different heart rhythms, but its ability to diagnose AF in real-world situations has not been adequately investigated. We sought to assess the diagnostic performance of a standalone smartphone PPG application, Cardiio Rhythm, for AF screening in primary care setting.
  
  
  
  Patients with hypertension, with diabetes mellitus, and/or aged ≥65 years were recruited. A single-lead ECG was recorded by using the AliveCor heart monitor with tracings reviewed subsequently by 2 cardiologists to provide the reference standard. PPG measurements were performed by using the Cardiio Rhythm smartphone application. AF was diagnosed in 28 (2.76%) of 1013 participants. The diagnostic sensitivity of the Cardiio Rhythm for AF detection was 92.9% (95% CI] 77-99%) and was higher than that of the AliveCor automated algorithm (71.4% [95% CI 51-87%]). The specificities of Cardiio Rhythm and the AliveCor automated algorithm were comparable (97.7% [95% CI: 97-99%] versus 99.4% [95% CI 99-100%]). The positive predictive value of the Cardiio Rhythm was lower than that of the AliveCor automated algorithm (53.1% [95% CI 38-67%] versus 76.9% [95% CI 56-91%]); both had a very high negative predictive value (99.8% [95% CI 99-100%] versus 99.2% [95% CI 98-100%]).
  
  
  
  The Cardiio Rhythm smartphone PPG application provides an accurate and reliable means to detect AF in patients at risk of developing AF and has the potential to enable population-based screening for AF.
authors.affiliation: Cardiology Division, Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
authors.forename: Pak-Hei
authors.initials: PH
authors.lastname: Chan
authors.affiliation: Cardiology Division, Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
authors.forename: Chun-Ka
authors.initials: CK
authors.lastname: Wong
authors.affiliation: Cardiio Inc., Cambridge, MA.
authors.forename: Yukkee C
authors.initials: YC
authors.lastname: Poh
authors.affiliation: Department of Family Medicine and Primary Healthcare, Hong Kong East Cluster, Hong Kong, China.
authors.forename: Louise
authors.initials: L
authors.lastname: Pun
authors.affiliation: Department of Family Medicine and Primary Healthcare, Hong Kong East Cluster, Hong Kong, China.
authors.forename: Wangie Wan-Chiu
authors.initials: WW
authors.lastname: Leung
authors.affiliation: Department of Family Medicine and Primary Healthcare, Hong Kong East Cluster, Hong Kong, China.
authors.forename: Yu-Fai
authors.initials: YF
authors.lastname: Wong
authors.affiliation: Department of Family Medicine and Primary Healthcare, Hong Kong East Cluster, Hong Kong, China.
authors.forename: Michelle Man-Ying
authors.initials: MM
authors.lastname: Wong
authors.affiliation: Cardiio Inc., Cambridge, MA cwdsiu@hku.hk mingzher@cardiio.com.
authors.forename: Ming-Zher
authors.initials: MZ
authors.lastname: Poh
authors.affiliation: Department of Family Medicine and Primary Healthcare, Hong Kong East Cluster, Hong Kong, China.
authors.forename: Daniel Wai-Sing
authors.initials: DW
authors.lastname: Chu
authors.affiliation: Cardiology Division, Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China cwdsiu@hku.hk mingzher@cardiio.com.
authors.forename: Chung-Wah
authors.initials: CW
authors.lastname: Siu
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001281:Atrial Fibrillation / Q000175:diagnosis*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D063731:Mobile Applications; D017156:Photoplethysmography; D011237:Predictive Value of Tests; D011320:Primary Health Care; D012680:Sensitivity and Specificity; D000068997:Smartphone
keywords: atrial fibrillation; mobile app; photoplethysmography; screening