Tv and movies show them as a magical heart restart machine, bringing people back from the dead. But I’ve heard medical professionals say that’s not true, but they never elaborate. I’ve seen portable ones everywhere, so they must be needed fairly regularly.
In: 73
Several reasons!
Some background, the heart’s job is to basically contract in specific places at specific times to squeeze blood through your arteries to get oxygen to all your organs and cells. To coordinate this specific type of movement, ie a heartbeat, an electrical signal originates in one part of the heart and travels to other parts of the heart via a specific pathway, allowing everything to contract precisely when it’s supposed to.
Sometimes for whatever reason that electrical pathway can get messed up and instead of a single coordinated signal, you get multiple electrical impulses firing off when they’re not supposed to, which in turn causes parts of the heart to contract when they’re not supposed to, which leads to blood not getting squeezed forward to your organs (including your brain, which is why people in this situation will often feel lightheaded/pass out).
In the cases of two specific abnormal rhythms – called ventricular fibrillation and pulseless ventricular tachycardia – delivering a big electrical shock basically “resets” the heart – essentially, all the ions needed to create an electrical current are temporarily depleted all at once, giving a window for the natural automatic electrical signaling intrinsic to the heart to jump in and get everything coordinated again.
This means that defibrillators don’t work like in the movies for several reasons:
They won’t work if you have zero electrical activity going on (asystole or pulseless electrical activity).
They won’t work if you don’t have one of the specific two rhythms above, eg you have an atrial tachycardia instead of ventricular, you have a pulse, you are in sinus rhythm, etc.
Most importantly, movies usually show a person getting shocked and recovering immediately without any issues, but in real life many people who end up in situations where they need a defibrillator are very, very sick already – they have significant cardiac disease already or are having a massive heart attack, their electrolytes are all wacky, something else was wrong with their heart’s electrical system already, etc. And that’s not even going into the potential consequences of your brain being deprived of oxygen for a long time. Movies never seem to show the many months of rehab a patient might have to undergo after getting defibrillated, or the family gathered at the bedside being told that their loved one’s brain has suffered massive injury and they are unlikely to ever make a significant recovery.
So I guess TL;DR: you can only defibrillate in very specific circumstances, and defibrillation does not equal 100% recovery to baseline?
Latest Answers