Heart failure outcomes in low-risk patients with atrial fibrillation: a case-control study of 680 523 Swedish individuals

Aims: Knowledge of long-term outcomes in patients with atrial fibrillation (AF) remains limited. We sought to evaluate the risk of new-onset heart failure (HF) in patients with AF and a low cardiovascular risk profile.

Methods and results: Data from the Swedish National Patient Register were used to identify all patients with a first-time diagnosis of AF without underlying cardiovascular disease at baseline between 1987 and 2018. Each patient was compared with two controls without AF from the National Total Population Register. In total, 227 811 patients and 452 712 controls were included. During a mean follow-up of 9.1 (standard deviation 7.0) years, the hazard ratio (HR) for new-onset HF was 3.55 [95% confidence interval (CI) 3.51-3.60] in patients compared with controls. Women with AF (18-34 years) had HR for HF onset 24.6 (95% CI 7.59-80.0) and men HR 9.86 (95% CI 6.81-14.27). The highest risk was within 1 year in patients 18-34 years, HR 103.9 (95% CI 46.3-233.1). The incidence rate within 1 year increased from 6.2 (95% CI 4.5-8.6) per 1000 person-years in young patients (18-34 years) to 142.8 (95% CI 139.4-146.3) per 1000 person-years among older patients (>80 years).

Conclusions: Patients studied had a three-fold higher risk of developing HF compared with controls. Young patients, particularly women, carry up to 100-fold increased risk to develop HF within 1 year after AF. Further studies in patients with AF and low cardiovascular risk profile are needed to prevent serious complications such as HF.