EKG Interpretation, part 8: Ventricular Rhythms

by Cathy Parkes

Full Transcript

In this video, we are going to talk about ventricular rhythms. If you recall from one of my previous videos, the inherent rate of a ventricular rhythm is very slow. It's between 20 and 40 beats per minute. With a ventricular rhythm, there will not be a P wave and the QRS complex will be wide. So it will be over 0.12 seconds in duration, or over three small boxes wide. So in this video, we will be covering premature ventricular complexes, ventricular tachycardia, torsades de pointes, ventricular fibrillation, idioventricular rhythm, as well as asystole.

Okay, so when we look at this strip, we can see that the right-hand side of this strip looks really normal. We've got nice little P waves, followed by a nice narrow QRS complex.

Our rhythm looks regular and our rate looks about right, but what went down over here?

Well, what went down is a premature ventricular complex or PVC. So a PVC is an abnormal impulse that originates from the ventricle and occurs early.

So with a PVC, the premature complex will not have a P wave, so you don't see a P wave here, and the QRS complex will be very wide. So it is definitely over three small boxes wide.

So PVCs are often and asymptomatic and don't require treatment. However, antiarrhythmics can be used for patients who have symptomatic PVCs.

Okay, in this strip we have ventricular tachycardia.

So you can see we have these wide QRS complexes. They're definitely over 3 small boxes wide.

We don't have any P waves. These QRS complexes are wide, but they are regular, so our ventricular heart rhythm is regular.

So in terms of heart rate, if I kind of measure the distance between these QRS complexes, there's about 10 small boxes between them. So 1500 divided by 10 is 150 beats per minute, so we're definitely experiencing tachycardia here.

So in terms of treatment of ventricular tachycardia, if the patient has a pulse, then we can treat it with either cardioversion or antiarrhythmics. However, if the patient has ventricular tachycardia without a pulse, then we need to treat immediately with defibrillation.

Okay, in this rhythm we have something called torsades de pointes, which I hope I'm saying that right. I might be butchering it, because it's definitely not above me to butcher a name.

So when we look at this strip, this doesn't look anything like a normal EKG strip. We don't have nice little P waves and QRS complexes so these are all QRS complexes that are abnormally wide and kind of random. They have this inconsistent appearance.

And if you look at these waves, they kind of appear to twist around the EKG baseline. So anytime you see this kind of abnormal P wave that kind of twists around the baseline, that will be torsades de pointes.

The heart rate of this is high. So you can see between these QRS complexes, there's only four or five small boxes. So we definitely have a heart rate over 100 beats per minute, which is what you would expect with this dysrhythmia.

And in terms of treatment, treatment of torsades de pointes, usually, includes administration of IV magnesium. Other treatment options include antiarrhythmics as well as pacing. So a pacemaker may be necessary for this patient as well.

Here, in this strip, we have what's called ventricular fibrillation or V-fib.

So it's difficult when you see this to really assess the heart rate.

There's no P waves to assess.

These QRS complexes are replaced with these V-fib waves instead. So if you see something that looks like just a bunch of little bumps down here like this, then that's V-fib.

And in terms of treatment, you're going to want to do immediate defibrillation. So the hint here is defib, V-fib.

Here, we have an idioventricular rhythm.

So you can see we don't have any P waves here. So there's no P waves, and we have a really wide QRS, which is how we know that we are dealing with a ventricular rhythm. So we can't assess the regularity of the atrial rhythm because we don't have P waves, but we can assess the regularity of the ventricular rhythm. And it is regular; there's an equal distance between the QRS complexes.

So this is going to be a very slow heart rate, we can already tell. But if we calculate it, there's about 43 small boxes between these QRS complexes. So if I take 1,500, divide it by 43, the heart rate is going to be 35.

So with ventricular rhythms, and with an idioventricular rhythm such as this, we can expect a slow heart rate that would be under 40 beats per minute. So with this one, we have 35 beats a minute, so that definitely fits the bill for an idioventricular rhythm.

It is possible to have an accelerated ventricular rhythm, which would have a heart rate that would be over 40, but for a normal idioventricular rhythm, we would expect a heart rate under 40.

So in terms of treatment, idioventricular rhythms are typically transient and often don't require treatment at all.

Finally, here, we have asystole. So this is the rhythm you never want to see on your patient, but you always want to see on your exam because it's pretty easy to pick out, right? So this is asystole.

The heart rate is zero.

There's no atrial or ventricular heart rhythm.

There's no P wave.

There's no QRS complex.

And you will need to perform CPR on a patient with asystole pronto. Okay?

Of course, if your patient is up and talking and you see this rhythm, chances are that their tele leads are just not on, so definitely use your common sense.

But if your patient is unresponsive and you see asystole, then definitely get going on the chest compressions.

That wraps up ventricular rhythms, and in my next video, we will start talking about heart blocks. So thank you so much for watching!

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