Thomas Henden wrote in 000211 MMDIgest:

> The revolutionary solution was to make a heart/pump that 'softly'
> and gently squeezed the blood through with no abrupt or turbulent
> movements in opposition to a metal valve or turbine pump.

Yes, even in the 1960's the eddies were known to cause clotting.  How
to keep a turbulent flow throughout was then considered the fix, but
not attained yet, by the speaker I heard.

Now there is a common pump that runs by squeezing a roller along a
rubber tube; actually it is done in a circle with three or more
rollers.  They are in chemical equipment supplier catalogs for fluid
transfer.

A big one could feature silence, but not efficiency, as the mechanical
losses of the rubber (or of course now Teflon tubes, etc.) are higher
than the old pumps.

The body uses about 100 watts power, so 35 to 40 watts is a good guess
for the heart, 10 watts would be low, i.e., sleeping.

Will Herzog
Rochester NY