Validation of a Novel Smartphone-based Photoplethysmographic Method for Ambulatory Heart Rhythm Diagnostics - the SMARTBEATS study.

Abstract

In the current guidelines, smartphone-photoplethysmography (PPG) is not recommended for diagnosis of atrial fibrillation (AF), without a confirmatory electrocardiogram (ECG) recording. Previous validation studies have been performed under supervision in healthcare settings, with limited generalizability of the results. We aim to investigate the diagnostic performance of a smartphone-PPG method in a real-world setting, with ambulatory unsupervised smartphone-PPG recordings, compared with simultaneous ECG recordings and including patients with atrial flutter (AFL). Unselected patients undergoing direct current cardioversion for treatment of AF or AFL were asked to perform one-minute heart rhythm recordings post-treatment, at least twice daily for 30 days at home, using an iPhone 7 smartphone running the CORAI Heart Monitor PPG application simultaneously with a single-lead ECG recording (KardiaMobile). PPG and ECG recordings were read independently by two experienced readers. In total, 280 patients recorded 18,005 simultaneous PPG and ECG recordings. Sufficient quality for diagnosis was seen in 96.9% (PPG) vs 95.1% (ECG) of the recordings (p < 0.001). Manual reading of the PPG recordings, compared to manually interpreted ECG recordings, had a sensitivity, specificity, and overall accuracy of 97.7%, 99.4% and 98.9% with AFL recordings included, and 99.0%, 99.7% and 99.5% respectively with AFL recordings excluded. A novel smartphone-PPG method can be used by patients unsupervised at home to achieve accurate heart rhythm diagnostics of AF and AFL with very high sensitivity and specificity. This smartphone-PPG device can be used as an independent heart rhythm diagnostic device following cardioversion, without requirement of confirmation with ECG.