Detection of increased left ventricular filling pressure (LVFP) is paramount in the evaluation and treatment of patients with left heart failure, yet difficult to assess directly at the bedside. Although inferior vena cava (IVC) examination can detect increased right atrial pressure, a used surrogate for high LVFP, this assumption has not been directly tested. We evaluated whether assessment of IVC size and respirophasic variation could be used to predict increased LVFP. Seventy-two patients with chronic heart failure underwent right heart catheterization and limited echocardiographic examination focused on the IVC. IVC size and collapsibility were evaluated for their ability to predict a wedge pressure>or=15 mm Hg. In conclusion, an IVC maximum dimension of 2.0 cm and IVC collapsibility of 45% were the optimal cutoffs to predict an increased pulmonary capillary wedge pressure, with sensitivities of 75% and 83% and specificities of 83% and 71%, respectively.