they went to operate on an old womans throat wich is the pathway to her lungs= bad idea
from my own experience when ever my lungs closed up for a second this happens every now and then my heart will start beating real fast then i go to take in a huge deep breath. or if im so relaxed at night this will sometimes happen while im watching tv or leaning in a way my upper body is almost upside down this will happen i will somewhat struggle to breath while my heart picks up its pace
the heart speeds up because it realizes not enough oxygen is there, the heart is almost like its own entity you cant control it but you can deprive it from its resources slowing it down or speeding up the heart
when they operated on joan rivers they shocked her vocals and her lungs causing them to contract in a way that they didnt inhale oxygen properly (someone fucked up in not seeing this coming, they fucked up big time not realizing the link). so when that fella but that device to her throat it shocked her breathing system paralyzing it this then causes the heart to tick up and essential have a heart attack till the heart dies/ explodes/ or simply stops
pretty sad to see someone die even if they were just doing dumb shit trying to make people laugh, but you should never get surgery for anything never put your life in someones hands
why was she even getting throat surgery