At present, there is not accurate way to determine specific flow rates for axial flow ventricular assist devices (VADS). If a right heart cath is needed for these patients for clinical purposes, they will also undergo a cardiac CT scan while the pulmonary artery catheter is in place. It is possible to visualize the flow rates of axial flow VAD's and determine a more accurate rate per specific patient.

Data Analyzed with following results:

Article in Press for Cardiopulmonary Support and Physiology, results state "Pairwise comparison of calculated output from left ventricular assist devices is feasible using first pass dynamic computed tomography test bolus technique versus thermodilution output measurements yielded good agreement (P=.03). The output calculated using dynamic CT underestimated the thermodilution output measurement by 0.54+ 0.37 L/min (95% confidence interval 0.66-0.94).

Description as listed in Summary. The hemodynamic data collected along with pump parameters may help determine more accurate flow rates specific to each patient.

Inclusion Criteria:

• Signed Informed consent

Patients with implanted left ventricular assist devices referred for CT scans