The impact of exercise on ventricular arrhythmias in adults with tetralogy of Fallot

Background: Sudden death of presumed arrhythmic etiology is the leading cause of mortality in adults with tetralogy of Fallot. Objectives: To assess the impact of exercise on ventricular arrhythmias in adults with tetralogy of Fallot. Methods: Adults with repaired tetralogy of Fallot were randomized in a 2: 1 ratio to an open-label trial of standard care versus 12 weeks of supervised combined aerobic/resistance training with continuous Holter monitoring. Proportion of premature ventricular complexes (PVC) and runs of non-sustained ventricular tachycardia (NSVT) were assessed by mixed and Poisson regression models with generalized estimating equations for repeated measures. Results: A total of 152 Holters were performed in 17 patients, median age 35 (interquartile range [IQR] 28, 42) years, 65% male, 13 of whom were randomized to exercise training. Baseline characteristics were similar between groups. Exercise training resulted in significant increases in peak oxygen uptake (11 +/- 19%, p=0.028), metabolic equivalents (11 +/- 18%, p = 0.027), and exercise duration (8 +/- 10%, p = 0.009) compared to no changes in controls. Frequent (>= 30 per hour) PVCs were present in 46% of patients, couplets in 62%, and 3 to 7 beat runs of NSVT in 31%. The median proportion of PVCs was 1.93 parts per thousand (IQR 0.41, 5.89) at baseline and 1.45 parts per thousand (IQR 0.08, 2.76) during the initial exercise session (p = 0.722), and remained stable over time (beta coefficient = -0.031, p = 0.408). Runs of NSVT decreased significantly over time (beta coefficient = -0.032, p = 0.018). Conclusion: In adults with repaired tetralogy of Fallot, exercise training is safe, improves exercise capacity, and appears to confer a beneficial effect on ventricular arrhythmias. (C) 2016 Elsevier Ireland Ltd. All rights reserved.