A blood pump with an interatrial shunt for use as an electrohydraulic total artificial heart.

: A recently designed blood pump subsystem for the completely implantable electrohydraulic total artificial heart (EHTAH) has been developed and is under evaluation. The subsystem consists of joined left and right ventricles, atrial cuffs with an interatrial shunt (IAS), and two outflow grafts. The ventricles were developed to fit within the pericardial space based on the results of anatomic fit trials. An optimized configuration for animal use, which was adaptable for human use with minimal modification, was identified. The core dimensions of the ventricles with an energy converter are approximately 10 x 11 x 7 cm. Maximum output and stroke volume are 9.2 L/min and 81 ml, respectively. The IAS is used to balance the volumetrically coupled EHTAH, and is made by forming an orifice in the common septum of the left and right atrial cuffs. Performance and durability of the IAS were examined in animal experiments for up to 9 days. The diameter of the IAS was 3.4-5.5 mm, and the left-right atrial pressure difference ranged from 2 to 10 mmHg, with 0.57-1.48 L/min of theoretically calculated shunt flow. No evidence of thrombus formation was found in or around the IAS at autopsy. The entire EHTAH system with a new blood pump is being assembled for long-term animal studies.