BACKGROUND: Small ventricular septal defects (VSDs) are considered to be without hemodynamic influence and most remain unrepaired. However, studies recently described late cardiac adverse consequences that could potentially affect functional capacity. Yet, this has never been assessed in adulthood. Therefore, the aim was to determine peak exercise capacity in adults with small VSDs compared with healthy, matched controls.

METHODS: In a prospective, cohort study we included patients with unrepaired VSDs and healthy controls, (age 18 to 40years). Functional capacity was determined through incremental bicycle tests and gas exchange was measured breath-by-breath with Jaeger MasterScreen CPX®. Primary endpoint was peak oxygen uptake, while secondary endpoints were anaerobic threshold and health-related quality-of-life.

RESULTS: In total, 34 VSD patients (age 26.5±6years) and 28 controls (age 26.9±5years) were included. There were no differences between groups in demographic characteristics or habitual exercise levels. At peak exercise, patients reached lower peak oxygen uptake, 36.2±9ml/kg/min, compared with controls, 43.8±6ml/kg/min (p=0.002) along with lower maximal workload; patients 3.2±1 watt/kg and controls 3.8±1 watt/kg (p=0.001). Aerobic capacity was also poorer in patients, 24.5±8ml/kg/min compared with controls, 31.2±7ml/kg/min (p=0.005). Lastly, patients had lower health-related quality-of-life in terms of physical (p=0.017) and social functioning (p=0.003) compared with controls. In the patient group physical functioning was directly correlated to the impaired peak oxygen uptake (r=0.473, p=0.005).

CONCLUSION: We demonstrated reduced subjective and objective functional capacity in small, unrepaired VSDs compared with controls. Furthermore, a correlation was seen between the impaired peak exercise capacity and lower self-estimated physical health.