Exercise capacity in adult patients with tetralogy of Fallot

Background: On a group level, patients with repaired tetralogy of Fallot have impaired exercise capacity. Since exercise capacity is related to prognosis, and more patients survive into higher age, it is important to know the expected exercise capacity at different ages. Furthermore, factors associated with exercise capacity and the relation between exercise capacity and mortality need further evaluation. Methods: The national register of congenital heart disease was searched for exercise tests in adults with repaired tetralogy of Fallot. The results from exercise tests were compared with national reference data. Results: 314 patients were identified (median age 33.2 [IQR 24.8-44.7], 40.8% women). The mean percent of predicted workload was 74.8 (±19.6) % without change across ages. In multivariable analysis, NYHA class I (odds ratio [OR]4.2, 95% confidence interval [CI]1.7-10.0) and higher physical activity level (>3 h/week) (OR 3.6, 95%CI 1.8-7.3) were positively associated with higher exercise capacity, while ongoing cardiovascular therapy (OR 0.4, 95%CI 0.2-0.7) and male sex (OR 0.3, 95%CI 0.2-0.6) were negatively associated with higher exercise capacity. Both exercise capacity (HR 0.96, 95%CI 0.93-0.98) and heart rate reserve (HR 0.96, 95%CI 0.94-0.98) were associated with mortality. Conclusions: In patients with repaired tetralogy of Fallot the exercise capacity was approximately 75% of expected, regardless of age. Patients with better NYHA class and high physical activity level had a higher exercise capacity. Low exercise capacity and low heart rate reserve were associated with higher mortality. Therefore, evaluating exercise capacity as part of follow up is of importance