Louisville, Ky. ? One year ago, Tom Christerson’s life was ebbing away when he made the decision to let doctors take out his failing heart and put in a revolutionary mechanical pump.

Now, as he prepares to mark the first anniversary of his operation this week, the retired tire dealer has become a silver-haired symbol for the AbioCor artificial heart and its potential as a replacement for diseased hearts.

Of seven people implanted with the device, the 71-year-old Christerson is the lone survivor. He went home in April to Central City, Ky., resuming a quiet life with a close-knit circle of family and friends.

The AbioCor has not skipped a beat since being inserted into Christerson’s chest last Sept. 13, according to its manufacturer, Abiomed Inc. of Danvers, Mass.

The softball-sized pump, made of plastic and titanium, is powered by batteries. It is self-contained within the chest with no wires or tubes sticking through the skin, a technological leap from earlier mechanical hearts, like the Jarvik-7, that were attached by wires and tubes to machinery outside the body.

Among all artificial heart recipients, William Schroeder of Jasper, Ind., lived the longest, surviving 620 days with a Jarvik-7 until his death in 1986. The first artificial heart recipient, Barney Clark, a Seattle-area dentist, lived 112 days after receiving a Jarvik-7 in 1982.