In vitro flow characteristics of the Jarvik-7 prosthesis with respect to filling pressure, stroke frequency, and systolic duration.

The Jarvik-7 total artificial heart (TAH), as an implantable substitute for the natural heart, has become the most widely used prosthesis. Although the performance of the Jarvik-7 prosthesis has been described experimentally as well as clinically, the interrelationship between cardiac output, filling pressure, stroke frequency and systolic duration in a wider perspective has not been reported. Our in vitro evaluation of the pump demonstrates the relation between cardiac output and right filling pressure in the range of 2-17 mm Hg with a stroke frequency varying between 60-130 beats per minute with 40% and 50% systolic duration. With respect to complete ventricular filling, a safer and wider range of right filling pressures and stroke frequencies could be employed to produce various cardiac output values at 50% systolic duration as compared to 40% systolic duration. When complete diastolic filling was present, particularly with a high stroke frequency and a low systolic duration, an increase of the left filling pressure to an extent which in a clinical situation would probably cause pulmonary oedema, was observed. By using a right Jarvik-7/70 ml ventricle and a left Jarvik-7/100 ml ventricle, this buildup of the left filling pressure was completely avoided.