11.   As the first recipient of a self-contained artificial heart enters his fourth week with the device, his surgeons say his recovery continues to exceed their expectations.

12.   At that rate, the artificial heart never would be finished.

13.   At the same time, research and development expenses increased dramatically, in large part because of the clinical trials of the artificial heart.

14.   Because the heart is removed, the use of the total artificial heart is a drastic, final step in heart treatment.

15.   Both artificial hearts seem to work, at least in calves.

16.   Both recipients have an AbioCor artificial heart, which is made by Abiomed of Danvers, Mass.

17.   A decade after that unhappy experience, however, researchers have opened a new chapter in the long saga of artificial hearts.

18.   A new type of artificial heart offered a glimmer of hope to victims of heart disease.

19.   Abiomed designed its artificial heart to operate quietly.

20.   Abiomed has kept the artificial heart beating in the laboratory for more than a year without mechanical failure, Lederman said.