Heart failure over time in patients with screening detected atrial fibrillation - a postdoc analysis of the STROKESTOP and STROKESTOP II studies

Background Atrial fibrillation (AF) is one of the most common arrythmias globally and is associated with a high risk of stroke, heart failure (HF) and death. Although stroke is a feared complication, heart failure is a more frequent outcome and a leading cause of mortality in patients with AF. HF also increases the risk of AF, and when both conditions coexist, AF may accelerate HF progression and independently increase all-cause mortality. Early identification and treatment of HF may therefore provide clinical benefit in patients with AF. Aim The aim of this study is to determine the incidence and timing of heart failure in patients with screening-detected AF, and to compare outcomes with patients with known AF and those without AF in two large population-based AF screening studies. Methods This post hoc analysis included participants without prior HF from the STROKESTOP and STROKESTOP II randomized screening studies where individuals aged 75–76 years were invited to ECG-based AF screening. Data on new HF diagnoses and mortality were obtained from national registries. Incidence rates were calculated per 100 person-years, and Cox regression was used to estimate hazard ratios (HRs) for incident HF across groups. Results In STROKESTOP, 6824 participants and 12 898 controls without previous HF were included. After a median follow-up of 6.9 years (IQR 6.5-7.2), 21% of the participants (54/252) with screening detected AF developed HF, corresponding to an the incidence rate of 3.56 per 100 person-years (95% CI 2.68–4.65) in screening detected AF, compared with 4.38 in participants with known AF, 1.04 in participants without AF, 4.79 in controls with known AF, and 1.45 in controls without AF. In STROKESTOP II, 6601 participants and 12 905 controls without previous HF were included. After a median follow-up of 5.1 years (IQR 5.0–5.8), 20% of the participants (31/152) with screening-detected AF developed HF, corresponding to an incidence rate of 4.19 per 100 person-years (95% CI 2.84–5.94), compared with 3.52 in participants with known AF, 0.93 in participants without AF, 4.90 in controls with known AF, and 1.32 in controls without AF. Conclusion Individuals with screening-detected AF have a comparable risk of developing heart failure as patients with clinically known AF and a threefold higher risk than those without AF. These findings indicate that screening-detected AF is not a benign condition and highlight the potential importance of echocardiographic evaluation and early HF prevention in this groupCumulative incidence of HF in AF