Atrial fibrillation was associated with a significantly higher risk of sudden cardiac death in a matched cohort of young individuals aged 0-35 years (HR 7.93; 95% CI 2.39-26.32).
Cohort (n=4,420,000)
Yes
Does atrial fibrillation increase the risk of sudden cardiac death and all-cause mortality in young individuals aged 0-35 years?
Atrial fibrillation is an independent risk factor for sudden cardiac death and all-cause mortality in young individuals aged 0-35 years, even after adjusting for other cardiovascular conditions.
Hazard Ratio: 7.93 (95% CI 2.39–26.32)
Abstract Background Atrial fibrillation (AF) is the most common heart rhythm disorder and sudden cardiac death (SCD) is a major public health concern. Growing evidence indicates an association between AF and SCD1-2, yet research into the relationship has been challenged by shared risk factors between AF and ischaemic heart disease, diabetes, and heart failure - prevalent conditions also commonly associated with SCD. Purpose We aimed to investigate our hypothesis that AF remains associated with a higher risk of SCD in young individuals, independent of ischaemic heart disease, diabetes, and heart failure. Methods This study was performed as a Danish, register-based, nationwide, matched cohort study using the Sudden Cardiac Death in the Young Register from 1st January 2000 to 31st December 2019 in individuals aged 0-35 years. Follow-up began at the latest of 1st January 2000, date of immigration, or date of birth. Exposure was defined as presence of an AF diagnosis. Outcomes of interest were SCD and all-cause mortality without SCD (ACM). Follow-up ended at the first date of SCD, ACM, emigration, 35th birthday, or 31st December 2019. Multivariable cause-specific cox regression models were employed with age as a time scale, adjusted for sex, ischaemic heart disease, diabetes, heart failure, and cancer, with results presented as hazard ratios (HR) of SCD and competing risk of ACM. Then, a 1:4 matching of exposed AF patients with unexposed non-AF patients upon sex, birth-year in 2-year intervals, entry time, ischaemic heart disease, diabetes, heart failure, dilated cardiomyopathy, and hypertrophic cardiomyopathy - was performed. Results are presented as cumulative incidences from time of AF diagnosis/matching and HR of SCD and competing risk of ACM. Results The study included 4.42 million individuals, of which 4,346 had AF. Average ages were 14 years (51% male) in non-AF patients versus 29 years (68% male) in AF patients. Compared with non-AF patients, AF patients had a significantly higher HR of SCD: 16.32 (CI: 9.61-27.70) and ACM: 7.45 (5.95-9.32) respectively. After adjustments, AF patients retained higher HR of SCD (4.76 (CI: 2.53-8.96) and ACM (5.01 (CI: 3.95-6.36). Post matching of 3414 AF patients to 13,656 non-AF patients, cumulative incidences of SCD and ACM remained higher in AF patients with HR of SCD of 7.93 (CI 2.39-26.32) and ACM of 6.02 (CI 3.97-9.11). Conclusion(s) This study suggests that AF remains a risk factor for SCD and ACM in the young population, even after adjusting for ischaemic heart disease, diabetes, and heart failure. This association persisted in the matched cohort, further matched upon dilated and hypertrophic cardiomyopathy. Future studies should explore which features define AF patients at highest risk of SCD, examining potential underlying mechanisms. This could help determine whether AF could warrant inclusion in SCD risk assessment for implantable cardioverter defibrillator implantation in young individuals.Multivariable Cox Models
Rajan et al. (2025) conducted a cohort in Atrial fibrillation (n=4,420,000). Atrial fibrillation vs. No atrial fibrillation was evaluated on Sudden cardiac death (SCD) (HR 7.93, 95% CI 2.39-26.32). Atrial fibrillation was associated with a significantly higher risk of sudden cardiac death in a matched cohort of young individuals aged 0-35 years (HR 7.93; 95% CI 2.39-26.32).