Abstract 3931: The Genetic Component in Atrial Fibrillation: a Study in Danish Twins
Background: Atrial fibrillation (AF) is the most common arrhythmia but the precise mechanisms behind the disease is still unknown. Genetic aspects seem to play a role. Data from The Framingham Heart Study has shown that parents with AF is a risk factor for AF in the offspring and that this increase in risk is higher for maternal than paternal AF.
Hypothesis: Atrial fibrillation is to some extent a heritable condition and due to shared genetic material, monozygotic twins having a co-twin with AF have a higher risk of being diagnosed with AF than dizygotic twins having a co-twin with AF.
Aim: To study the risk of AF in twins as a function of zygosity and diagnostic status of the co-twin.
Methods: 1,729 Danish pairs of twins with one twin having a diagnosis of AF, were identified by merging The Danish Twin Registry and The National Patient Registry. Of these 434 were monozygotic, 894 dizygotic same-sex and 401 dizygotic opposite-sex. Participants were included at the time their co-twin were diagnosed with AF and all were in sinus-rhythm at baseline. Participants were followed until AF occurred or until end of follow-up, whichever came first.
Results: During a total follow-up time of 7,598 years, 120 of the 1,729 participants were diagnosed with AF. Monozygosity was associated with an increase in risk of AF compared to dizygosity (hazard ratio: 2.2 (95% CI: 1.5–3.1)). This effect was more pronounced in women than in men (hazard ratios: 2.4 (1.3– 4.3) and 2.0 (1.2–3.2)).
Conclusion: The risk of AF given that the co-twin is diagnosed with AF, is doubled for a monozygotic twin compared with a dizygotic twin. This effect is more pronounced when the first twin diagnosed is female.