Natural History and Clinical Predictors of Atrial Tachycardia in Adults With Congenital Heart Disease.

BACKGROUND: Atrial tachycardias (ATs) are a significant source of morbidity in adults with congenital heart disease (CHD). This study evaluates the incidence and clinical predictors of AT in a cohort of patients with CHD. METHODS AND RESULTS: We included 3311 adults (median age at entry 22.6 years, 50.6% males) with CHD (49% simple, 39% moderate, and 12% complex) prospectively followed up in a tertiary center for 37 607 person-years. Predictors of AT were identified by multivariable Cox regression analysis accounting for left truncation. An external validation was performed in a contemporary cohort of 1432 patients. Overall, 153 (4.6%) patients presented AT. AT burden was highest in complex CHD, such as single ventricle (22.8%) and d-transposition of the great arteries (22.1%). Hazard rates of AT across lifetime, age at presentation, and the time lapse between surgery and the first AT episode varied among the most common CHD. Independent risk factors for developing AT were univentricular physiology, previous intracardiac repair, systemic right ventricle, pulmonary hypertension, pulmonary regurgitation, pulmonary atrioventricular valve regurgitation, pulmonary and systemic ventricular dysfunction. At the age of 40 years, AT-free survival in patients with 0, 1, 2, and ≥3 risk factors was 100%, 94%, 76%, and 50%, respectively. These findings were confirmed in the validation cohort. CONCLUSIONS: Natural history of AT differed among the most common forms of CHD. Simple clinical parameters, easily obtained by noninvasive means, were independent predictors of AT in adults with CHD. Although risk was negligible in patients without any of these factors, their addition progressively increased AT burden.