Increased risk of thromboembolic events in adult congenital heart disease patients with atrial tachyarrhythmias.

Background: Atrial tachyarrhythmias are a major morbidity in patients with adult congenital heart disease (ACHD). However, few studies have investigated risk stratification of thromboembolic events in ACHD patients with atrial tachyarrhythmias.

Methods And Results: This retrospective cohort study reviewed the clinical records of 2314 ACHD patients from 1977 to 2014. We found 242 (10.4%) patients with atrial tachyarrhythmias and excluded 84 patients already being treated with anticoagulant therapy. The remaining 158 patients without anticoagulant therapy were retrospectively followed up from the onset of atrial tachyarrhythmia to the incidence of thromboembolic events. Fourteen thromboembolic events and 5 hemorrhagic events occurred. All patients with thromboembolic events had atrial fibrillation (AF). Thromboembolic events occurred even in the patients with low or intermediate risk as indicated by CHADS or CHADS-VASc score. Event rates were higher than those in data from the general adult population in previous studies. Univariate analysis revealed that age≥60years (OR 4.54, 95% CI 1.47-14.06, P=0.009), vascular disease (OR 7.83, 95% CI 1.19-51.53, P=0.032), and persistent AF (OR 5.60, 95% CI 1.73-18.11, P=0.004) were the independent risk factors of thromboembolic events.

Conclusions: ACHD patients with atrial tachyarrhythmias and even those with low or intermediate risk as indicated by the CHADS or CHADS-VASc score had a higher risk of thromboembolic events. Therefore, anticoagulation should be considered earlier than in the general population in patients with risk factors of age≥60years, vascular disease, or persistent AF.