Characterization of natural and total artificial heart acceleration

The pulsatile nature of an implanted total artificial heart (TAH) may have several deleterious effects. To define the level of TAH impact, acceleration was measured and compared with that of the natural heart in a series of in vivo and in vitro experiments. In TAH implantations in calves, miniature accelerometers were incorporated onto the housing of a Utah-100 left ventricle. Identical accelerometers were glued to felt pledgets to obtain measurement of radial cardiac acceleration when sewn to the epicardial surface of the natural heart. Measurement of natural and artificial heart acceleration was made both intraoperatively and postoperatively in several animals. Many pumping conditions were also investigated with a similarly instrumented UVAD 85 left ventricle during in vitro testing. The peak natural heart acceleration measured was nearly 2 g both intraoperatively and at rest. Treadmill exercise or epinephrine infusion produced twice the resting peak acceleration value of the natural heart. Artificial heart peak acceleration as great as +/- 100 g was found intraoperatively and postoperatively. Peak TAH acceleration could be reduced by allowing the ventricle to fill fully prior to the start of the next systole, by allowing the ventricle to fully eject prior to the next diastole, or by using a ventricular pressurization waveform that has a smooth contour with a sinusoidal-like profile. The ability to lower TAH acceleration may lead to a reduction in undesirable consequences of TAH implantation.