Smartphone photoplethysmography demonstrated a pooled sensitivity of 94% and specificity of 97% for detecting atrial fibrillation compared to conventional ECG, though current evidence is limited by small, biased studies.
Meta-Analysis (n=11,404)
Does smartphone camera photoplethysmography (PPG) improve the detection of atrial fibrillation compared to reference ECG in adult participants?
Smartphone PPG shows high sensitivity and specificity for atrial fibrillation detection, but current evidence is limited by small, low-quality studies with a high risk of bias, necessitating larger independent trials.
Effect estimate: Sensitivity 94%, Specificity 97% (95% CI 92-95)
OBJECTIVES: Timely diagnosis of atrial fibrillation (AF) is essential to reduce complications from this increasingly common condition. We sought to assess the diagnostic accuracy of smartphone camera photoplethysmography (PPG) compared with conventional electrocardiogram (ECG) for AF detection. METHODS: This is a systematic review of MEDLINE, EMBASE and Cochrane (1980-December 2020), including any study or abstract, where smartphone PPG was compared with a reference ECG (1, 3 or 12-lead). Random effects meta-analysis was performed to pool sensitivity/specificity and identify publication bias, with study quality assessed using the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies-2) risk of bias tool. RESULTS: 28 studies were included (10 full-text publications and 18 abstracts), providing 31 comparisons of smartphone PPG versus ECG for AF detection. 11 404 participants were included (2950 in AF), with most studies being small and based in secondary care. Sensitivity and specificity for AF detection were high, ranging from 81% to 100%, and from 85% to 100%, respectively. 20 comparisons from 17 studies were meta-analysed, including 6891 participants (2299 with AF); the pooled sensitivity was 94% (95% CI 92% to 95%) and specificity 97% (96%-98%), with substantial heterogeneity (p<0.01). Studies were of poor quality overall and none met all the QUADAS-2 criteria, with particular issues regarding selection bias and the potential for publication bias. CONCLUSION: PPG provides a non-invasive, patient-led screening tool for AF. However, current evidence is limited to small, biased, low-quality studies with unrealistically high sensitivity and specificity. Further studies are needed, preferably independent from manufacturers, in order to advise clinicians on the true value of PPG technology for AF detection.
Gill et al. (2022) conducted a meta-analysis in Atrial fibrillation (n=11,404). Smartphone camera photoplethysmography (PPG) vs. Conventional electrocardiogram (ECG) was evaluated on Diagnostic sensitivity and specificity for atrial fibrillation detection (Sensitivity 94%, Specificity 97%, 95% CI 92-95). Smartphone photoplethysmography demonstrated a pooled sensitivity of 94% and specificity of 97% for detecting atrial fibrillation compared to conventional ECG, though current evidence is limited by small, biased studies.