Study of Adaptation of the Right Ventricle to Systemic Afterload

Right ventricle (RV) in sub-aortic position is a rare situation, mainly in two congenital heart defects: congenitally corrected transposition of the great arteries and complete transposition of the great arteries palliated by atrial switch. In these patients, increase of afterload leads to hypertrophy and late RV dilatation. The stress exercised on RV walls could play a role in adaptative mechanisms to systemic afterload. Beyond a remodelling threshold, it could cause fibrosis damage and RV systolic failure. Magnetic resonance imaging, which has a major potential in estimation of RV remodelling, wall stress and fibrosis, could shed light on RV adaptation to systemic afterload and evolution towards failure. Systemic RV remodelling and function could also depend on the neuro-hormone secretion and mechanical arterial properties, that have a direct influence on patients afterload. The first purpose of the study is to determine the adaptative mechanisms of RV to systemic afterload, and the mechanisms of RV failure, in patients with congenital heart disease and subaortic RV, using cardiac magnetic resonance imaging (CMR).The mechanisms are evaluated by measures of RV remodelling and RV wall stress using CMR. Second objectives are to evaluate these mechanisms using echography, arterial properties study and neurohormonal levels

Patients inclusion criteria:

• patients with a systemic right ventricle
• to have an insurance
• to obtain informed consent

Patients non-inclusion criteria:

• patients with cyanosis defined by a saturation ≤ 85% at rest
• patients with a ventricular septal defect non repaired at the time of inclusion
• contraindications normal MRI
• contraindication to achieving a stress test
• Glomerular Filtration Rate inf 30ml/mn/1.73m²
• physical or mental disability that does not allow to perform a cardiopulmonary exercise test
• patients with already severe allergy to gadolinium MRI contrast
• current Pregnancy
• patients who can not be monitored over the period of one year, patient participating in another research on the Treatment interacting with the neurohormonal system in particular the renin-angiotensin-aldosterone system

healthy subjects inclusion criteria:

• matched for age and sex + / - 5 years of an asymptomatic patient
• Normal ECG
• normal Echocardiography
• clinical examination prior
• Patient receiving an insurance
• Obtaining informed consent

healthy subjects Exclusion criteria:

• History of myocardial infarction-known or detectable on the ECG-abnormal Liver function tests
• Complete Blood Count
• electrolytes
• viral serology
• Primary or secondary cardiomyopathy-known or detectable on echocardiography
• History of thoracic radiotherapy or chemotherapy
• Contraindications MRI
• Counter-indication for performing a stress test
• Patient with severe renal clearance less than Glomerular Filtration Rate inf 30ml/mn/1.73m²
• Patient has already made a severe allergy to gadolinium MRI contrast Current Pregnancy