AUTHOR=Huntelaar Marthe J. , Selder Jasper L. , Hopman Luuk H. G. A. , Visser Marieke C. , Allaart Cornelis P. 

TITLE=Photoplethysmography-based atrial fibrillation detection in patients after crytpogenic stroke

JOURNAL=Frontiers in Stroke

VOLUME=Volume 3 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/stroke/articles/10.3389/fstro.2024.1496003

DOI=10.3389/fstro.2024.1496003

ISSN=2813-3056

ABSTRACT=Introduction
Undiagnosed atrial fibrillation (AF) is a potential underlying cause of cryptogenic stroke. Prolonged screening for AF using a photoplethysmography (PPG) smartwatch might offer a solution for detecting AF in patients with cryptogenic stroke. In this study, we aim to investigate this strategy by comparing AF detection rates using a PPG-smartwatch and 48h Holter monitor. 
Methods
From December 2019, patients with cryptogenic stroke were included to undergo 28 days of semi-continuous AF monitoring using a Fitbit smartwatch with a PPG-based FibriCheck algorithm, with simultaneous Holter monitoring during the first 48 hours. From April 2021, a detailed screening log was installed to characterize potential study participants.
Results
After logged screening of 1312 patients, enrollment was prematurely halted due to slower-than-expected inclusion rates. 40.8% of the screened patients had cryptogenic stroke, of which 92.5% were non-eligible for inclusion due to logistical, technological, and study-related challenges. Of the 43 patients enrolled, 37 completed PPG monitoring using a smartwatch. 43% of patients had PPG-detected AF in the 28 days after cryptogenic stroke. 
During the first 48 hours, PPG-based screening detected AF in 2 patients, whereas no AF was detected using concurrent Holter monitoring. 
Conclusion
The PPG-smartwatch detected AF in 43% of the participants after cryptogenic stroke. However, discrepancies with concurrent Holter monitoring raise major concerns about the accuracy of the detected PPG-based AF. Moreover, the feasibility of a PPG-based screening strategy is limited due to logistical and technological challenges, partly inherent to cryptogenic stroke patients.