Abnormal hepatic vein venous flow refers to inspiratory systolic predominance of hepatic vein forward flow, expiratory reduction of hepatic vein forward flow, or reversal of hepatic vein flow during diastole. During apnea, forward flow in the hepatic vein only occurs during ventricular systole, not diastole. During inspiration, systolic flow becomes exaggerated, and diastolic flow appears. Systolic flow is reduced to baseline during expiration, and diastolic flow becomes reversed. The reversal of hepatic vein diastolic flow occurs exactly when the tricuspid inflow is lowest.
