1. A medical device comprising: a lead assembly configured to be at least partially located proximate to the heart, the lead assembly including an extra-cardiac (EC) electrode to be positioned proximate to at least one of a superior vena cava (SVC) and a left ventricle (LV) of a heart, the lead assembly including a subcutaneous remote-cardiac (RC) electrode configured to be located remote from the heart such that at least a portion of the greater vessels are interposed between the RC electrode and the EC electrode to establish an extra-cardiac impedance (ECI) vector, and a processor module to measure extra-cardiac impedance along the ECI vector to obtain ECI measurements, the processor module assessing a hemodynamic performance assessment based on the ECI measurements.