Peripheral Pulse Volume (PPV) is the change in the volume of a limb that occurs when blood passes through the limb. The limb also acts as an electrical conductor whose electrical impedence changes with limb geometry and volume. Each time the heart beats, the volume of the limb segment changes, and therefore its electrical impedence changes. A plethysmograph can be used to mesure volume changes of a part of the body by producing a plethysmographic waveform. Selectively capturing a number of these plethysmographic wave forms with acceptable noise levels and averaging them using the EKG as a reference-timing signal generate a highly reproducible pulse volume signal. Signal averaged pulse volume measurement will be obtained non-invasively from the lower extremities of patient volunteers. A disposal non-occluding electrical monitoring strap will be applied to the calf of each patient. Changes in the calf's size/volume caused by changes in the patient's cardiac output and calf blood flow will result in electrical impedance changes. These changes will be recorded by an analog admittance plethysmograph attached to the lower extremity strap. The analog plethysmograph is coupled to a digital computer for signal enhancement and measurement.

Inclusion Criteria

• Coronary care unit patients with indwelling right heart (Swan Ganz) catheters with or without intraaortic balloon assist pumping devices.
• Congestive Heart Failure patients on and off various therapeutic inotropic agents with or without indwelling heart catheters
• Cardiac catheterization laboratory patients undergoing prophylactic IABP in the presence of left main or diffuse unstable CAD
• Chronic renal failure patients undergoing hemodialysis.
• Peripheral Vascular Disease patients
• Patients udergoing Tilt Table Testing
• Any patients undergoing right heart catheterization

Exclusion criteria -- Non specified