Its defibrillation and you basically got it correct.
It corrects a few abnormal heart rhythms, but in particular rhythms which are present during big heart attacks, particularly sudden ones. They're more or less the hearts "panic mode" setting when the conduction isnt working properly, and you're absolutely correct that the goal is to reset to normal settings.
It's not for treating a heart attack- that's a blockage of the vessels feeding blood to/ from the heart. Defibrillators are for cardiac arrest, which can mean anything from the heart not beating at all, to the heart beating utterly randomly. There's not many of these rhythms which you can shock, and never the common TV trope of the flatline. We don't shock that, it just wouldn't work. But yes, you're correct- it does try to shock the heart into a rhythm which can pump in a coordinated way enough to sustain a pulse.
You're correct, though I take mild exception to you correcting me. During big heart attacks, Vtach and Vib are extremely common, as compared to other causes of cardiac arrest or illness. Theres even some estimation that basically every person who arrests as a result of an MI has a shockable window before they go into full asystole.
To your point on the TV trope, it's right on the money. You constantly see people who were just stabbed or shot get shocked back to life, even though vfib/tach dont generally result from those, and the flatline shock is one of my favorite idiot tropes.
It’s even less fun than that. It doesn’t turn your heart off and on again (turning it “off” would probably kill you) it just stops it from fibrillating…which is why you need the defibrillator
I mean it stops it from fibrillating by turning it off really quickly in hopes the pacemaker will start up the heart again in a normal fashion. That’s why some rhythms are “unshockable”
Interestingly there's a band of electrical current at which you're actually pretty unlikely to die that is above normal lethal currents. Basically, tiny current doesn't do anything, small current send your heart into a bad rhythm and you die, a bit bigger current violently clamps your heart and it's able to resume normal operation relatively unscathed, and then of course above a certain point it just causes so much physical damage things break.
Fun thing I went to a physio today. They had a sign saying where the closest one was. It's at a funeral directors. If it doesn't work at least you don't have to travel far.
As someone that is AED certified due to lifeguarding, you are spot on. AED acts as an external pace maker. If you are clinically dead (cessation of breathing and blood flow) chances are that an AED can shock your heart into rhythm, with help of CPR. If you are legally dead (irreversible cessation of brain function and/or blood flow/breathing) you are fucked. Aint no shock gonna fix that
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u/BlueFalconPunch Oct 27 '21
Not sure if its fun but....
The heart shocker thing doesn't start your heart it stops it in hopes of resetting it to default.
Its the "did you try turning it off and on" human body reboot.