Craig Lewis had no pulse for a month before he passed away, but he was certainly still alive.
A new artificial heart, developed by Dr. Billy Cohn and Dr. Bud Frazier of the Texas Heart Institute, kept the 55-year-old cardiac amyloidosis patient alive without producing a pulse or showing a beep on an EKG machine, according to NPR. The continuous flow device, which is yet to have been specifically named, used a new system of screw-like rotor blades to push blood forward without pulsating.
As a result, Lewis had no pulse whatsoever. When his wife listened to his chest, all she heard was whirring.
It turns out, the body doesn't actually need a pulse, that's just how the heart works.
"The pulsatility of the flow is essential for the heart, because it can only get nourishment in between heartbeats," Cohn told NPR. "If you remove that from the system, none of the other organs seem to care much."
From the Texas Heart Institute:
The continuous-flow device consists of 2 turbine-like blood pumps implanted to replace the 2 sides of the patient's removed heart. These 2 pumps act as a man-made substitute for the natural heart. The left ventricular assist devices (LVADs) used are manufactured by Thoratec Corporation (Pleasanton, Calif.) and were approved by the US Food and Drug Administration in January 2010 for assisting the failing left ventricle (the heart's main pumping chamber) in patients suffering from terminal heart failure.
Prior to using the device on Lewis, the researchers had first experimented with it on 38 calves at their animal research facility. Today, a calf named Abigail resides at the facility with one of their devices and no pulse.
However, aside from listening to the machine itself, the lack of pulse makes it hard to tell if a patient is alive or dead. According to the institute, even EKG machines would register a person using the new heart as dead.
The device (Courtesy The Texas Heart Institute):