Congenital heart disease (CHD) is the leading cause of birth defects, with an incidence of 0.8%. Among CHD, univentricular heart disease or "single ventricle" is rare and complex. As a result of the improved patient care over the last decades, the number of children and adults with single ventricle is increasing significantly. Today, the main challenge is to ensure an optimal follow-up of these new patients in order to improve their life expenctancy as well as their quality of life (QoL). Currently, echocardiography and cardiopulmonary exercice test (CPET) are central in management of patients with single ventricle as part of good clinical practice guidelines.

Single ventricle volumes and function are very difficult to asses with conventional echocardiography because of their complex geometry. Indeed, single ventricle size and morphology vary depending on the patient characteristics and on the initial CHD (before surgical repair). That's why conventional 2D echocardiographic parameters are not reliable for single ventricle assessment.

Magnetic resonance imaging (MRI) is more effective in assessing single ventricle volumes and function. Nevertheless, MRI is not universally available, is not practical in many situations, is expensive, and is a relative contraindication in patients with pacemakers.

Over the past decade, the use of the 3D echocardiography has increased. This is an available tool that can assess ventricular function and volumes in few seconds. Recent studies shown a good correlation between 3D echocardiography and MRI for assessment of ventricular volumes and function in patient with CHD and especially in those with single ventricle.

Moreover, according to some authors, CPET parameters are strongly correlated with risk of hospitalization, risk of death, physical activity and quality of life, especially in patients with single ventricle.

To date, there is no study performed about the relationship between 3D echocardiography and CPET parameters in patients with single ventricle.

This is a cross-sectional, observational, multicenter, and prospective study Eligible patients will be included during their usual medical check-up. As recommended by guidelines, patients with single ventricle have an 2D echocardiography and a CPET annualy. Data required for this study will be collected from patient medical record.

3D echography data acquisition will be performed using 2D ultrasound post-processing by TOMTEC software. No supplementary visit, directly related to the research, will be necessary. This study does not change the usual care management of the patient.

Inclusion criteria:

• Patient over 8 years old with univentricular heart disease as defined by the ACC-CHD classification
• Agreement from adults or parents if minor patients
• CPET performed within the 6 months before or after performing echocardiography

Exclusion criteria:

• Cardiomyopathy unrelated to CHD (eg coronary artery disease, toxic cardiomyopathy)
• Significant clinical status change between performing CPET and performing echocardiography, according to the investigator's opinion

Patients with a single ventricle or univentricular heart

NC