Beyond the Pulse

Last night I watched Rachel Maddow's segment on the Man with No Pulse, who has long been unaffectionately known as Darth Vader at least partly because of his metaphorical heartlessness. (You can see the segment here.) Now technology has made him a man the left ventricle of whose heart has become a host to a rotary pump that runs on batteries that have to be frequently charged via a wall socket. (Making him, of course, the Man Who Plugged In-- though not my version, obviously.)

The pump-- known as a Left Ventricular Assist Device (LVAD)-- is usually a temporary expedient, pending a heart transplant. No announcement has been made by that, though the doctor Maddow interviewed said it was "not contraindicated." I'm curious about one thing not covered in the interview: does this mean that the blood is pumped at one constant speed, and that the pump is not responsive to input from hormones? And what happens to blood pressure, since blood vessels are continually dilating and contracting in line with local conditions? All I've been able to glean from Google-assisted browsing is that the chief significant side-effects are blood clots and infection, and that people wearing LVADs had improved blood pressure, sodium, blood urea nitrogen and creatine levels. But really, an sf writer would like to know more...