Ultra-short-term heart rate variability using a photoplethysmography-based smartphone application: a TeleCheck-AF subanalysis

Autonomic nervous system activation plays an important role in the pathophysiology of atrial fibrillation (AF). It can be determined using heart rate variability (HRV). We aimed to evaluate the feasibility of using photoplethysmography (PPG) recordings for the assessment of the ultra-short-term HRV.

TeleCheck-AF is a structured mobile health approach, comprising the on-demand use of a PPG-based smartphone application prior to a scheduled teleconsultation to ensure comprehensive remote AF management. Participants with at least one PPG recording in sinus rhythm were included to assess resting heart rate, root mean square of successive differences (RMSSD), patient compliance and data consistency. In total, 855 patients [39.4% women] with 13 465 recordings were included. Patient compliance was 95.2% (IQR 76.2–114.3%). Median heart rate per patient was 66.5 (IQR 60.0–74.0) b.p.m., median RMSSD per patient was 40 (IQR 33–50) ms and median recording consistency was ±5.2 (IQR 3.8–7.0) b.p.m. and ±14.8 (IQR 9.3–21.1) ms, respectively. RMSSD was lower in men than women, in patients with CHA₂D₂-VA-Score 0, with a history of AF, and following ablation of AF. Older age and lower body mass index were associated with higher RMSSD.

The ultra-short-term HRV can be determined in 1-min PPG recordings with high user compliance and high inter-recording consistency within a structured mobile health AF management approach. The strategy used in this study may also be feasible for the management of other conditions in which the HRV plays a role for diagnostics and therapy.