The Significance of Exercise-Induced Repolarization Abnormalities in Patients with Congenital Heart Disease

All articles of this category (opens in new window) Background: Exercise testing remains a cornerstone in the diagnostic work-up and risk stratification of coronary artery disease. However, the prevalence and potential clinical relevance of exercise-induced ischemia-associated repolarization abnormalities (RA) in patients with congenital heart disease (CHD) have not been systematically investigated and were, therefore, investigated in this mono-center study. Methods: A total of 483 treadmill and bicycle exercise tests were retrospectively analyzed. Recordings were evaluated for significant RA, newly emerging conduction abnormalities, and arrhythmias, and compared with findings from invasive coronary angiography obtained within 180 days after or prior to an exercise test. Results: Over an 8-year period (2014–2021), 483 patients (male: n = 262) with a median age of 17.5 years were included. CHD was present in 239 patients (49%), with the most common diagnosis of obstruction of the right (24%) or left (20%) outflow tract, left-to-right shunt (13%), Fontan circulation (8%), and systemic right ventricle (7%). The most common diagnosis in patients without CHD was cardiomyopathies (21%), rhythmological congenital or inherited disorders (16%), or symptoms and arrhythmias leading to further workup (53%). New significant RAs were observed in 23 patients (5%) during exercise without a difference in patients with or without CHD. In 74 patients (15%), coronary angiography revealed pathological findings, which were significantly more common in patients with CHD (25%) than in non-CHD patients (6%, p < 0.0001). Of these, 76% already demonstrated RAs at rest, whereas new and significant RAs were documented in only 3 of these 74 patients (4%). In contrast, exercise-induced rhythmological abnormalities (mainly premature beats) were found in 32% of tests and were more common in patients with than without CHD (43% vs. 22%, p < 0.001). Newly emerging conduction abnormalities during exercise were rare (2.7%). Conclusion: In this cohort of young patients with CHD, significant new ECG alterations during exercise testing were uncommon despite a relatively high proportion of pathological coronary angiographies. Conversely, the absence of significant RAs cannot be regarded as evidence against coronary pathology, and further imaging modalities remain indicated in cases with clinical suspicion of coronary artery disease. The observation of a relatively high prevalence of arrhythmic abnormalities in patients with CHD requires further investigation. Publication History Article published online: 17 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany