FIGURE 10.-Arterial replacement of silastic. Note partial adherent thrombus (clot) near the line of anastomosis. The thrombus is non-adherent, the main body having already broken away. noted on the cage of various types of valves. A later model pump uses a cageless ball valve, both in the inflow and outflow tracts. This is a direct copy of the old original Hufnagel valve. The interior of the valves, however, has been lined with woven Dacron to anchor the fibrin which would inevitably collect on the surface. A recent clinical application demonstrated the pump's effectiveness in decreasing left atrial pressure during an acute episode of left ventricular failure. The pump increased urinary output as well as decreasing left atrial pressure. The external pulsing unit, which is a pneumatic "flip-flop" that can be timed electrically and synchronized with the electrocardiogram, is shown in figure 16 (p. 216). The clinical application of the left ventricular bypass is currently being reserved for rapidly failing patients for whom no other methods of treatment are applicable. The experience gained clinically will be accumulated and used to broaden the possibilities for further application in the future. What the future holds for the artificial heart can only be extrapolated from our present knowledge and experience. Certainly the problem of total heart replacement will have to be solved along with the problem of powering such a device. These are by no means simple problems. In another 3 to 5 years we may have total heart replacement but without implantable power. Implantable power, I would venture a guess, could not come within 10 years. What sources are there for implantable power? Potentially, we have electrical, thermonuclear, and biologic power. All of these are being investigated currently in various laboratories throughout the United States. |