The doctors and nurses stand around the patient's bedside, engrossed in whatever heroic and far-fetched treatment they just pulled out of their asses to save the un-saveable patient. And then you hear it, the unmistakable tone of the always-gonna-happen flatline! Dutifully the doctor turns to the monitor and grabs the defibrillation paddles; paddles which don't exist anymore on any machine that is less than twenty years old. But none-the-less, those monophasic joule-senders get ripped off and rubbed together; never mind that they never placed any defibrillation gel on the paddles for them to rub together, they will be rubbed together anyway, as though this act in and of itself is what gives them the 360 joules they need to shock life back into the clinically dead patient lying before them. The paddles are placed and the life-giving energy is sent into the patient, arcing their back in a way that no clinician in real life has ever seen. "Again!" they cry, letting slip the electrical dogs of war. And as you watch, you know that this patient is a minor character, so minor he is without a name, whose only credit at the end will be "First patient casualty - John Smith". And with this knowledge comes the inevitable outcome that is "Time of death..." Of course, had the patient been George Clooney or Bruce Willis, the flatline would have converted to a stable normal sinus rhythm and all would have been okay.
But is this really how it goes?
In real life, doctors, nurses, paramedics and other clinicians adhere to the Advanced Cardiac Life Support (ACLS) protocols provided to us by the American Heart Association (AHA). The protocols are fairly simple and get minor updates every 2-5 years depending on what studies have come around to prove or disprove current treatment modalities. While there are many parts to ACLS, this article will focus on the defibrillation and synchronized cardioversion aspects of ACLS.
Flatlines are actually not really flat, unless the patient has been deceased for quite a while. Asystole is usually a little wavy showing the trace amounts of electricity still moving through the heart. In this rhythm, the proper course of action is to start chest compressions, provide ventilations, and then give epinephrine 1:10,000 1mg via IV every 3-5 minutes. By the way, epinephrine is the exact same thing as adrenaline - but that's another article. You do that for about 10-20 minutes, depending on circumstances, and then wrap it up. So that would be pretty boring for a TV show to watch CPR for 20 minutes and so they shock instead.
The rhythms that we do in fact shock are Ventricular Tachycardia, Ventricular Fibrillation, Atrial Fibrillation, Atrial Flutter, and Supra-Ventricular Tachycardia. We do pace bradycardia which is a type of electrical therapy but different than what we are talking about here. And when we do shock, there are two types of electrical delivery; one is called defibrillation and the other is called synchronized cardioversion.
Ventricular Fibrillation (V-Fib) and Ventricular Tachycardia (V-Tach) are when the lower chambers of the heart, the ventricles, begin moving in a rhythm that isn't conducive to life. The top image is V-Fib where the ventricles are jiggling around jello on a platter and they aren't contracting at all - and of course ventricular contraction is where we push blood from the heart into the rest of the body; kind of important. The bottom image is V-Tach, where the ventricles are contracting but they're contracting too fast and without the aid of the atriums above them. Again, this is bad because it reduces and can even eliminate the ejection of oxygenated blood out to the rest of the body.
If a patient is in V-Fib, they will not have a pulse. If they are in V-Tach, they may or may not have a pulse. If V-Fib is present, or V-Tach WITHOUT a pulse is present, then we defibrillate the patient. We place the pads onto the patient and charge the machine to 200 joules. Then we press the button on the machine to deliver the shock. The picture below shows where we place the pads which have pictures themselves to remind the clinician where to place them.
All of the other rhythms are shocked with what is called synchronized cardioversion. That's when the patient still has a pulse with the underlying arrhythmia and we want to use electricity to stop the heart and hope that it starts back up in the proper rhythm. This is the medical equivalent of, "Did you try turning it off and then on again?" Ctrl-Alt-Delete at 120 joules (or the proper energy for the associated rhythm). The reason it is called "synchronized" is because the machine will track the wave forms you see below and shock precisely on top of the "R-Wave" which is the top of the peak you see in each of the complexes below. Where as defibrillation just sends electricity at whatever point you press the button, regardless of what phase of contraction the heart is in.
So let's stop shocking those flatlines! Put your patient into V-Tach or V-Fib if you want to shock them. And if you want to look really cool to all of your medical providers in the audience, sync-cardiovert some unstable SVT on a patient with an altered mental status; that will show that you are a totally legit writer who does their homework.