Atrial Fibrillation Screening With Photo-plethysmography Through a Smartphone Camera

Frederik H. Verbrugge; Tine Proesmans; Johan Vijgen; Wilfried Mullens; Maximo Rivero-Ayerza; Hugo Van Herendael; Pieter Vandervoort; Dieter Nuyens

Disclosures

Europace. 2019;21(8):1167-1175. 

In This Article

Abstract and Introduction

Abstract

Aims: This cross-sectional study was set up to assess the feasibility of mass screening for atrial fibrillation (AF) with only the use of a smartphone.

Methods and results: A local newspaper published an article, allowing to subscribe for a 7-day screening period to detect AF. Screening was performed through an application that uses photo-plethysmography (PPG) technology by exploiting a smartphone camera. Participants received instructions on how to perform correct measurements twice daily, with notifications pushed through the application's software. In case of heart rhythm irregularities, raw PPG signals underwent secondary offline analysis to confirm a final diagnosis. From 12 328 readers who voluntarily signed up for screening (49 ± 14 years; 58% men), 120 446 unique PPG traces were obtained. Photo-plethysmography signal quality was adequate for analysis in 92% of cases. Possible AF was detected in 136 individuals (1.1%). They were older (P < 0.001), more frequently men (P < 0.001), and had higher body mass index (P = 0.004). In addition, participants who strictly adhered to the recommended screening frequency (i.e. twice daily) were more often diagnosed with possible AF (1.9% vs. 1.0% in individuals who did not adhere; P = 0.008). Symptoms of palpitations, confusion, and shortness of breath were more frequent in case of AF (P < 0.001). The cumulative diagnostic yield for possible AF increased from 0.4% with a single heart rhythm assessment to 1.4% with screening during the entire 7-day screening period.

Conclusion: Mass screening for AF using only a smartphone with dedicated application based on PPG technology is feasible and attractive because of its low cost and logistic requirements.

Introduction

The lifetime risk for atrial fibrillation (AF) development in the general population is estimated at ~25%.[1] By 2030, 14–17 million AF patients are anticipated in the European Union, with 120–215 thousand new diagnoses per year.[2] Atrial fibrillation is independently associated with a two-fold increased risk of all-cause mortality in women and a 1.5-fold increase in men.[3] Early diagnosis and appropriate treatment, particularly with oral anticoagulation in persons at high risk for stroke or systemic embolism, may mitigate this risk and prevent substantial morbidity.[1]

In the general population, current European Society of Cardiology guidelines recommend opportunistic screening by pulse taking or electrocardiogram (ECG) rhythm strip in individuals >65 years of age (Class I, Level B).[1] In addition, systematic screening with an ECG may be considered in patients >75 years or those at high stroke risk (Class IIb, Level B).[1] Because such screening efforts are cumbersome and expensive when implemented on a large scale, they are unlikely to be cost-effective in population groups at lower risk.

Interestingly, recent innovations in AF screening strategies and development of new screening devices have the potential to increase screening coverage at relatively low cost and efforts.[4] Blood pressure devices with algorithms based on pulse irregularity, dedicated AF screening devices based on single- or multiple-lead ECG, and smartphone applications have all shown promise in this respect. Smartphone applications using photo-plethysmography (PPG) technology through their build-in camera are particularly attractive as no additional hardware is needed and smartphone use is likely to become—if not already is—ubiquitous in the real-world setting, paving the way for mass screening. Small studies on PPG-based screening for AF have already demonstrated excellent sensitivity of 87–100% with an acceptable specificity of 90–97% against the 12-lead ECG as gold standard.[5–11] The current study was set up to assess the feasibility of mass screening for AF through a smartphone-based algorithm using PPG technology by the only CE approved application that has been recently developed.[12]

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