Medicine breakthrough: living without pulse with an artificial heart

Two doctors at the Texas Heart Institute in Houston have made a great leap in medicine this spring, giving a dying man an artificial heart in order to maintain his life. The surgery was successful, but had an unusual side effect: the patient had no pulse.

After testing the artificial heart on 38 cows, Dr. Billy Cohn and Dr. Bud Frazier changed Craig Lewis’ defunct heart. A month later, Lewis died from other medical causes, but his artificial heart worked flawlessly, doctors say.

Frazier and Cohn turned on the artificial heart with the help of two ventricular assist devices that help make the blood flow through the body with a rotor, not with a pump that would pulsate the blood. Some studies show that these devices work longer than traditional pumps because there is only one function of movement, that of the rotor.

Pointing to a healthy calf after the tests, Cohn argues that, “If you examined her arteries, there’s no pulse. If you hooked her up to an EKG, she’d be flat-lined…. By every metric we have to analyze patients, she’s not living.”

The ventricular assist device that usually increases one side of the heart (the left one) has been used since the 80s, although in time it has become smaller. The controversial idea that people don’t need pulse in order to live was a buzz around 2010, when former Vice President Dick Cheney received a continuous-flow HeartMate II pump to replace his left ventricle, thus becoming a living person with no pulse. A connection was made between two HeartMate II devices, thus replacing the heart entirely.

“What we’ve kind of done is taken two motorcycles, strapped them together, and called it a car,” says Cohn.

Cohn and Frazier are convinced that this new method of transplantation will become common in the future. Unlike other transplants, this one never gets old. Cohn argues that too many researchers are trying to recreate the pulse, motivating that all animals have one. In case the pulse is removed “from the system, none of the other organs seem to care much,” he says.

At present, Cheney and thousands of other ventricular assist devices carry a hard and uncomfortable battery pack that is connected to the pump through a wire that goes through the abdomen, creating a space in which an infection can easily penetrate. Fortunately, an engineer and a heart surgeon have just launched a prototype of a battery pack that charges the device without the need for wires.

Also, this device raises many questions and difficulties, including the idea that people having this device should wear some bracelets with labels explaining to first aid doctors why they don’t have pulse.