Impedance cardiography technology, along with recent advances in the impedance cardiography (ICG) device, has become a provocative but not yet proven noninvasive alternative to invasive hemodynamic measurements. The results from stroke volume and cardiac output measurements by ICG show reasonably accurate correlation to the values calculated from direct measurements from pulmonary artery catheters. ICG may be a useful adjunct to clinical judgment for heart failure patients. The available data would not yet support supplanting invasive hemodynamic assessment in the critical care setting with ICG. Future studies and advances in technology are expected to improve impedance cardiography, thus broadening its clinical applications. Ongoing research must confirm the precise benefits of this information for ICG monitoring to become a standard assessment in heart failure.