BACKGROUND: There are increasing reports of cardiac and exercise dysfunction in adults with small, unrepaired ventricular septal defects (VSDs). The primary aim of this study was to evaluate pulmonary function in adults with unrepaired VSDs, and secondly to assess the effects of 900 μg salbutamol on lung function and exercise capacity.

METHODS: Young adult patients with small, unrepaired VSDs and healthy age- and gender-matched controls were included in a double-blinded, randomised, cross-over study. Participants underwent static and dynamic spirometry, impulse oscillometry, multiple breath washout, diffusion capacity for carbon monoxide, and ergometer bicycle cardiopulmonary exercise test.

RESULTS: We included 30 patients with VSD (age 27 ± 6 years) and 30 controls (age 27 ± 6 years). Patients tended to have lower FEV1, 104 ± 11% of predicted, compared with healthy controls, 110 ± 14% (p = 0.069). Furthermore, the patient group had lower peak expiratory flow (PEF), 108 ± 20% predicted, compared with the control group, 118 ± 17% (p = 0.039), and showed tendencies towards lower forced vital capacity and increased airway resistance compared with controls. During exercise, the patients had lower oxygen uptake, 35 ± 8 ml/min/kg (vs 47 ± 7 ml/min/kg, p < 0.001), minute ventilation, 1.5 ± 0.5 l/min/kg (vs 2.1 ± 0.3 l/min/kg, p < 0.001) and breath rate, 48 ± 11 breaths/min (vs 55 ± 8 breaths/min, p = 0.008), than controls.

CONCLUSION: At rest, young adults with unrepaired VSDs are no different in pulmonary function from controls. However, when the cardiorespiratory system is stressed, VSD patients demonstrate significantly impaired minute ventilation and peak oxygen uptake, which may be early signs of parenchymal dysfunction and restrictive airway disease. These abnormalities were unaffected by the inhalation of salbutamol.