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

BackgroundSudden death of presumed arrhythmic etiology is the leading cause of mortality in adults with tetralogy of Fallot.ObjectivesTo assess the impact of exercise on ventricular arrhythmias in adults with tetralogy of Fallot.MethodsAdults 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.ResultsA 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‰ (IQR 0.41, 5.89) at baseline and 1.45‰ (IQR 0.08, 2.76) during the initial exercise session (p = 0.722), and remained stable over time (ß coefficient = − 0.031, p = 0.408). Runs of NSVT decreased significantly over time (ß coefficient = − 0.032, p = 0.018).ConclusionIn adults with repaired tetralogy of Fallot, exercise training is safe, improves exercise capacity, and appears to confer a beneficial effect on ventricular arrhythmias.