Post-ablation home monitoring using smartphone mechanocardiography: early detection of atrial fibrillation recurrence and association with re-ablation

Background Recurrence of atrial fibrillation (AF) after catheter ablation remains a major clinical challenge. Early identification of AF recurrence may facilitate timely decision-making regarding repeat ablation or medical therapy, potentially improving long-term outcomes. Traditional ECG-based home monitoring is effective but often limited by cost, patient adherence, and feasibility for continuous follow-up. Mechanocardiography (MCG), which detects cardiac-induced microvibrations using smartphone motion sensors, represents a novel, low-cost, and widely accessible alternative for remote rhythm monitoring. Purpose To assess the feasibility and clinical impact of the smartphone-based CardioSignal MCG application for early AF recurrence detection following catheter ablation, and to explore its association with repeat ablation procedures. Methods This retrospective, single-center study included 640 patients who underwent AF ablation and were offered complimentary access to the CardioSignal app for home-based rhythm monitoring. AF recurrence was defined as ≥1 episode of AF detected by the app within six months post-ablation, categorized as early (months 1–3) or late (months 4–6) recurrence. In a subcohort, subsequent re-ablation procedures were identified using the Danish National Ablation Database. Results Of the 640 patients who underwent AF ablation, 521 (81%) activated the CardioSignal application, and 354 (68%) remained active six months post-procedure. App engagement was highest during the first month, with a median of 6 active measurement days per patient (IQR 1–25), decreasing to 3 days by month six (IQR 0–9). Across the cohort, AF recurrence was detected in 40% of users during the early follow-up period (months 1–3, corresponding to the blanking period) and in 30% during the late period (months 4–6)(Figure 1). Most recurrences occurred within the first three months, indicating a temporal clustering of AF detection soon after ablation (Figure 2). In the subpopulation (n = 167; mean age 67 years; 62% male; 49% paroxysmal AF; 28% prior ablation), a total of 25 patients (15%) underwent repeat ablation within 7–14 months post-procedure follow-up. Early AF recurrence was strongly associated with subsequent re-ablation: 21 of 76 (27.6%) with early recurrence required re-ablation, compared with only 4 of 88 patients (4.5%) without early recurrence (χ² ≈ 15.9, p < 0.001, Cramer’s V of 0.30, moderate effect size). Conclusion Use of the smartphone-based CardioSignal MCG app enabled effective, large-scale home monitoring and early detection of AF recurrence after ablation. Active users with early AF recurrence were approximately six times more likely to undergo repeat ablation, suggesting that smartphone-based MCG monitoring may enhance post-ablation follow-up and support earlier, data-driven clinical decision-making.