BACKGROUND HHT patients with liver vascular malformations (VMs) may develop high-output cardiac failure requiring liver transplant in few cases. OBJECTIVE Our aim is to show that echocardiography is a good tool to evaluate the severity of hepatic vascular malformations in HHT and can improve medical management in HHT patients. METHODS The study is a cross-sectional study of cardiac parameters in HHT patients with dyspnea in a single referral center. All HHT patients with dyspnea, consecutively seen at HHT reference center in Lyon between May 2007 and November 2009 were included and had hepatic vascular Ultrasound and Echocardiography. Echocardiographic measures included cardiac output (CO) and index (CI), left ventricle (LV) filling pressures, and pulmonary artery pressure. Then, patients were classified in 4 groups according to the severity: group 1 (normal values), group 2 with isolated high CI, group 3 with high CI and increased LV-filling pressures and group 4 with increased LV-filling pressures and pulmonary hypertension. RESULTS Fifty-two HHT-patients were analyzed. Eight patients were in group 1, 25 in group 2, 6 in group 3 and 13 in group 4. Age, NYHA class dyspnea, edema, atrial fibrillation, hepatic artery diameter, and BNP (brain natriuretic peptide) levels significantly increased from groups 1 to 4 as well as left atrial area, and presence of mitral regurgitation. Patients with associated pulmonary VMs (n=11) did not show any clinical or echocardiographic differences. CONCLUSIONS Performing echocardiography in HHT patients with dyspnea allowed us to better understand the physiological processes of high-CO failure complicating liver vascular malformations and may improve follow-up of patients and treatment decisions.