Half-Heart Replacement

In Los Angeles, where doctors gathered for the annual meeting of the American Heart Association, much of the attention was also given to adventurous surgery. Although an entire artificial heart may be as far from medical achievement as man's dream of reaching the outer planets, Houston's daring Surgeon Michael E. DeBakey described a novel device that for three days took over a great deal of the work of one diseased heart.

Three Times & Out. The patient was a man of 42, whose aortic valve was so covered with chalky deposits that it did not let enough blood flow through from the heart to the rest of the body. Dr. DeBakey's surgical team replaced the damaged valve with an artificial caged-ball valve, but the man's heart was in such poor condition that on the following day it stopped. He had to be restored to life by open-chest massage. The trouble now, the doctors believed, was that the left ventricle, the lower chamber that does the heart's most important pumping, had been too weakened by longstanding disease to carry its load.

For the third time the surgeons cut open the man's chest. They hooked him up to a heart-lung machine while they did an unprecedented operation: they installed a substitute for the left ventricle. The gadget has the shape and size of a small banana, is made of a silicone plastic, and has a caged-ball valve in each end. The surgeons cut an opening in the left auricle, the upper chamber of the heart, and stitched in one end of the plastic tube. They cut a hole in the wall of the aorta and stitched in the other end of the tube. The ball valves were so placed that the one near the auricle would let blood into the tube, but not back out; the valve at the other end would let blood out, but not in.

By itself, such a setup would accomplish nothing. But surrounding the inner, straight-through tube is a jacket from which another tube leads outside the body to an air pump. When the pump pushes air into the jacket, the inner tube is squeezed; blood is forced out into the aorta. When the pump relaxes, the inner tube expands again and pulls blood into itself from the auricle.

Time for Recovery. The device worked well enough to restore the patient's blood pressure and electrocardiogram to near normal. He died, after 3 1/2 days, of widespread damage to several organs, all stemming from his earlier disease and not from failure of his half-heart pump.

No comparable device has yet been developed to allow a patient to keep it in permanently. But Dr. DeBakey thinks that many more heart-attack victims would recover if they could be tided over the first week or so. This is the time when the damaged heart, particularly its left ventricle, is least able to support the rest of the body, or even to maintain a full flow of blood through its own coronary arteries. The intrathoracic pump, as Dr. DeBakey calls it, should give the left ventricle a rest cure and time to regain its strength.

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