Pulmonary arterial hypertension (PAH) in patients with congenital heart disease usually develops secondary to chronic volume overload of the pulmonary circulation following left to right shunt. This overload leads to elevated pulmonary artery pressure (PAP) and later to increased pulmonary vascular resistance (PVR), leading to right ventricular dysfunction, considerable morbidity and even mortality.

Since PAH nowadays is mostly detected when symptoms occur and PAP are elevated, the disease already evolved to an advanced stage and treatment is often initiated too late. Our research group standardized the technique for the detection of early pulmonary vascular disease by bicycle stress echocardiography. The investigators now aim to assess this exercise technique in a group of patients with ventricular septal defect.

Pulmonary arterial hypertension (PAH) in patients with congenital heart disease usually develops secondary to chronic volume overload of the pulmonary circulation following left to right shunt. This overload leads to elevated pulmonary artery pressure (PAP) and later to increased pulmonary vascular resistance (PVR). PAH may lead to right ventricular and right atrial dysfunction, which may implicate considerable morbidity and even mortality.

Since PAH nowadays is mostly detected when symptoms occur and PAP are elevated, the disease already evolved to an advanced stage and treatment is often initiated too late. Our research group standardized the technique for the detection of early pulmonary vascular disease by bicycle stress echocardiography. Exercise-induced pulmonary hypertension has been recognised as a clinical entity, but is not included in the current guidelines on pulmonary hypertension. Further research in this area might imply the need for revision of the current PAH detection and treatment strategy.

By performing stress echocardiography and cardiopulmonary exercise testing, the investigators want to reach the following objectives:

• To answer the question whether the abnormal increase in PAP during exercise, seen in patients with late atrial septal defect (ASD) type secundum closure, is also present in congenital heart disease (CHD) patients who were treated for other shunt lesions.
• To apply this early detection technique in a broader population of CHD patients and to better define the predictive value of an elevated PVR during exercise.

Inclusion Criteria:

• Male or female subjects with ventricular septal defect (VSD) repair at least 6 months before study enrolment
• No discrimination in type of VSD repair will be made (percutaneous or surgical)
• Subjects must be able to perform exercise testing

Exclusion Criteria:

• Other congenital heart disease
• PAH of any aetiology other than VSD
• Inclusion in other treatment protocols
• Impairment of organic function (renal, hepatic)
• Arterial hypotension (systolic blood pressure < 85 mmHg)
• Anaemia (Hb < 10 g/dl)
• Thrombocytopenia (< 50000/µl)
• Significant valvular disease, other than tricuspid or pulmonary regurgitation
• Chronic lung disease or total lung capacity < 80% of predicted value
• History of pulmonary embolism
• Cyanotic patients, patients in an unstable condition and patients who have to undergo re-intervention during the study