Beyond recurrence: a smartphone PPG-derived burden-survival visualization after atrial fibrillation ablation
M De Wever, J Erzeel, M Van Es, S Dhont, H Gruwez, D Nuyens, H Van Herendael, M Rivero, P Vandervoort, B Vandenberk, P Haemers, L PisonAbstract
Background
Assessment of atrial fibrillation (AF) ablation efficacy traditionally relies on time to first recurrence, an endpoint that insufficiently reflects clinical arrhythmia burden. AF burden has emerged as a more meaningful outcome, capturing both frequency and persistence of arrhythmia. Recently, burden-survival curves have been proposed to integrate AF burden into time-to-event analyses, but their reliance on continuous ECG monitoring using implantable loop recorders limits real-world applicability. Smartphone-based photoplethysmography (PPG) provides a pragmatic alternative for longitudinal monitoring, enabling assessment of clinically relevant AF burden and symptom-rhythm correlation after ablation.
Purpose
To present a novel PPG-based burden-survival curve derived from real-world daily rhythm monitoring and demonstrate its value in redefining interpretation of AF recurrence after ablation.
Methods
In a retrospective post-ablation cohort monitored using a structured smartphone PPG strategy, daily rhythm status was classified as AF, sinus rhythm, or no measurement. Patients performed twice-daily and symptom-triggered measurements, reviewed by a specialized arrhythmia nurse. Post-blanking AF recurrence was defined as ≥1 day with ≥1 PPG tracing classified as AF/AT/AFL, reflecting a pragmatic definition that differs from the traditional ECG-based criterion of arrhythmia lasting ≥30 seconds. AF burden was approximated using AF days (days with ≥1 AF/AT/AFL tracing), with days without measurements classified as no AF. Daily burden trajectories were aligned to time since ablation, incorporating an 8-week blanking period and 6-month follow-up, and aggregated to construct a PPG-based burden-survival curve.
Results
Among 343 patients, post-blanking AF recurrence occurred in 32.7% within 6 months after ablation. In patients with recurrence, median AF burden was low (3 AF days, IQR 1-15). Recurrence occurred exclusively during blanking in 12.5% and exclusively after blanking in 14%. Adherence was high initially (median 92.3% of expected measurements during the first 4 weeks) but declined over time (median 16.1% in final 4 weeks). The burden-survival curve revealed marked heterogeneity in AF burden among patients classified as having recurrence. While conventional survival analyses would suggest frequent treatment failure, integration of daily rhythm status demonstrated that many recurrences were limited and sporadic, contrasted by a smaller subset of patients with sustained high-burden AF. This approach reframes recurrence as a spectrum rather than a binary outcome and highlights the clinical value of burden-based assessment.
Conclusions
PPG based rhythm follow-up after AF ablation can be integrated in AF burden survival curves, which provides a pragmatic and clinically meaningful framework for evaluating rhythm control strategies by shifting focus from binary recurrence to patient-level AF burden.PPG-based burden-survival curveAdherence