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Introduction:Mechanical circulatory support (MCS) is an alternative or bridge to heart transplant but size and functional range of current devices limits utility. We performed in silicoanalysis of adult (CFTAH), pediatric (P-CFTAH) and infant (I-CFTAH) continuous-flow total artificial heart using virtual mock loop (VML).Methods:Blood flows, pressures, and volumes as they surge through a MCS-supported heart failure cardiovascular system were input to the VML. Hemodynamics were simulated using a lumped-parameters, systemic/pulmonary circulation, values for impedances, systolic and diastolic LV compliance, beat rate, blood volume and cardiac chambers. Pump support at 4.0 L/min condition was used for the 46 kg (BSA 1.4 ~13-y patient) and 1.5 L/min for the 10.5 kg (BSA .5 m2~ 1-y patient) models.Results:Simulations of CFTAH, P-CFTAH and I-CFTAH were compared (Fig. 1). For the 4.0 and 1.5 L/min conditions, residence time (RT) and hemolysis decreased, but pulse pressure also decreased. At 1.5 L/min, the P-CFTAH had 3.6 (1/.65 scale factor3) times the RT of the I-CFTAH. At 4.0 L/min, the CFTAH had 2.9 (1/.7 scale factor3) times the RT of the P-CFTAH. P-CFTAH pump would have ~50% the flow range of the larger CFTAH pump.Conclusions:This simulation successfully enabled cross-over analysis of different size CFTAH configurations. The larger pump demonstrated better pulse pressure, with increased RT, and thus blood recirculation per patient size. In a smaller device, shear stress is increased, but RT is also reduced. When choosing a device for an individual patient the potential pros and cons of each specific size pump should be considered.