[Doppler ultrasound of blood flow in the hepatic veins].

The blood flow in the hepatic veins can normally be studied easily by Doppler ultrasound. The pattern of blood flow in normal individuals is described, and its relation to the cardiac cycle and changing pressure in the right atrium. The blood flow shows variations in healthy persons, and may change in cases of heart disease and hepatic disease. Conditions such as atrial fibrillation, tricuspid regurgitation, abnormal relaxation, restrictive cardiomyopathy, constrictive pericarditis and cardiac tamponade are reflected in the hepatic veins, and the pattern of blood flow may help in diagnosis, and in grading the pathology. In cirrhosis and portal hypertension the heart-synchronous variation in velocity is reduced. This is due to increased resistance to blood flow across the liver and the pressure gradient becoming larger than the variations in pressure in the right atrium.