DYNAMIC IN-VITRO AND IN-VIVO PERFORMANCE OF A PERMANENT TOTAL ARTIFICIAL-HEART

In vivo characterization studies were performed to compare the dynamic in vivo performance of the Penn State/3M Health Care electric total a rtificial heart to existing in vitro data. Fully implanted systems wer e utilized including the artificial heart, controller, backup batterie s, compliance chamber, and transcutaneous energy transmission. Cathete rs were implanted to measure central venous pressure (CVP), left atria l pressure (LAP), right atrial pressure (RAP), pulmonary artery pressu re (PAP), and aortic pressure (AoP). Cardiac output (CO) was determine d from the implanted controller, and systemic vascular resistance (SVR ) was calculated. Steady state data were collected for each animal alo ng with data regarding the transient responses to changes in preload a nd afterload. Preload was manipulated through volume changes. Afterloa d changes were accomplished through vasoactive agents. Increased prelo ad caused little change in cardiac output because the pump output was nearly maximum at baseline. LAP, AoP, and SVR increased with increasin g RAP. Decreased preload caused a reduction in CO, LAP, and SVR. After load increase resulted in a slight decrease in flow and an increase in system power and SVR. Afterload reduction was accompanied by a decrea se in preload and a concomitant reduction in flow. Overall, the system response was similar to the response observed in vitro.