Atrial fibrillation: age at diagnosis, incident cardiovascular events, and mortality.

BACKGROUND AND AIMS: Patients with atrial fibrillation (AF) are at increased risks of cardiovascular diseases and mortality, but risks according to age at diagnosis have not been reported. This study investigated age-specific risks of outcomes among patients with AF and the background population. METHODS: This nationwide population-based cohort study included patients with AF and controls without outcomes by the application of exposure density matching on the basis of sex, year of birth, and index date. The absolute risks and hazard rates were stratified by age groups and assessed using competing risk survival analyses and Cox regression models, respectively. The expected differences in residual life years among participants were estimated. RESULTS: The study included 216 579 AF patients from year 2000 to 2020 and 866 316 controls. The mean follow-up time was 7.9 years. Comparing AF patients with matched controls, the hazard ratios among individuals ≤50 years was 8.90 [95% confidence interval (CI), 7.17-11.0] for cardiomyopathy, 8.64 (95% CI, 7.74-9.64) for heart failure, 2.18 (95% CI, 1.89-2.52) for ischaemic stroke, and 2.74 (95% CI, 2.53-2.96) for mortality. The expected average loss of life years among individuals ≤50 years was 9.2 years (95% CI, 9.0-9.3) years. The estimates decreased with older age. CONCLUSIONS: The findings show that earlier diagnosis of AF is associated with a higher hazard ratio of subsequent myocardial disease and shorter life expectancy. Further studies are needed to determine causality and whether AF could be used as a risk marker among particularly younger patients.

Clinical characteristics and risk factors of arrhythmia during follow-up of patients with idiopathic ventricular fibrillation.

AIMS: The current knowledge of idiopathic ventricular fibrillation (IVF) is limited. We aimed to investigate the nature of IVF, including clinical assessment and later diagnosis, and risk factors of implantable cardioverter defibrillator (ICD) therapy in the follow-up period. METHODS: Between 2007 and 2019 we systematically identified all patients from Rigshospitalet, Denmark, with a resuscitated sudden cardiac arrest (SCA) with no identifiable cause. All patients were followed routinely in the ICD outpatient clinic and the majority also in an inherited heart disease outpatient clinic. Outcomes were analysed with Cox regressions models and cumulative incidence curves. RESULTS: We identified 84 patients with an initial diagnosis of IVF; of these, three (3.6%) patients were later diagnosed with a cardiac disease. The remaining IVF patients (n = 81, median age 45 years; men 71.6%) were followed a median follow-up of 5.2 years (interquartile range, 2.0-7.6). A total of 24 (29.6%) patients had appropriate ICD therapy and 12 (14.8%) patients had inappropriate ICD therapy. No predominant type of ventricular arrhythmia at first appropriate ICD therapy was observed. Early repolarization at baseline was not associated with an increased risk of appropriate ICD therapy (P = .842). Repeated cardiac arrest at index SCA increased the risk of appropriate ICD therapy (hazard ratio, 2.63 [95% CI, 1.08-6.40; P = .033]). CONCLUSION: Most patients remained idiopathic throughout the follow-up period and the overall long-term prognosis of IVF was good. Repeated cardiac arrest at index SCA was a risk factor of appropriate ICD therapy and early repolarization was not associated with an increased risk of appropriate ICD therapy.