In February, we showed you Heart Stops Beating, Jeremiah Zagar’s short film about Texas Heart Institute surgeons Billy Cohn and Bud Frazier’s “continuous flow device”—an artificial heart that doesn’t beat, but rather, pumps the blood like water through a garden hose, leaving the patient with no pulse.

The device was first used on 55-year-old Houstonian Craig Lewis, with Zagar’s cameras in the operating room. The film premiered at the 2012 Sundance Film Festival.

Now, as the producers promised, Zagar has released a longer, more expository cut that includes more details on Lewis, who suffered from a condition called amyloidosis, and was twelve to 24 hours away from death before the surgery (he still died from the illness, which had spread to his lungs, five weeks later).

There is also additional background on Cohn and Frazier, as well as the device itself.

“If we had something on a shelf, in a box, that we could take off, and sew in as a replacement for the diseased heart, than anybody could get one when they needed one,” Cohn says. “That’s what Frazier and I are trying to do.” 

One scene shows Cohn assembling the pumps in his garage workshop, using a station of “things that were available from Home Depot. …This is cuttin’ and sewin’,” Cohn continues. “This is like putting together a balsa and tissue airplane.”

Watch the video above (it’s still not for the squeamish, and it’s still completely fascinating).