Hi, welcome to our video series on electrocardiogram.
This one is going to be fun. It's fairly dramatic.
We're going to be talking about ventricular tachycardia. I mean, this is the stuff that TV shows are made of.
So here's our friend, normal sinus rhythm. By this point, you might be saying,
why do you show us this every single time? Well, hey, I hope you're getting bored with this,
because that means you have learned how to recognize normal sinus rhythm.
Now we're back with our patients. This time, we need to check on this man.
After our previous discussions, at first glance, we definitely know
something is wrong with this ECG, but what exactly is it? Let's take a closer look.
Whoa, this ECG is ventricular tachycardia. It looks significantly different than normal sinus rhythm.
So before we go forward, I want you to stop and think about it. Well, normal sinus rhythm has P waves.
Do you see P waves in the strip? Normal sinus rhythm has a PR interval.
Nope, don't see one there.
What about a QRS that's less than 0.12.? Uh-huh, that ain't happening.
Can you see a T wave? No, we're in trouble. We know that tachycardia is fast.
Yep, that looks pretty fast.
And since it's ventricular tachycardia, we know the chamber that's involved.
So looking through this, again, we don't have a P wave, a PR segment.
We've got some weird looking things that we used to call a QRS complex,
but what is going on here? Well, look at our beating heart.
How does that look different than what you saw in normal sinus rhythm?
Whoa, what's going on in the top half of the heart?
Yeah, this is why ventricular tachycardia is called ventricular tachycardia.
All the electrical activity is happening in the ventricles.
So V tach is a cardiac dysrhythmia where there are abnormal electrical impulses in the ventricle.
I mean, look at that heart, that clearly does not look efficient, does it?
The patient may be alert, but they'll probably feel dizzy, short of breath or have chest pain.
Now why would that be?
Well, looking at that heart, how efficient do you think it is?
I mean, you know, that you need the atrium to empty and relax and the ventricle to fill and squish, right?
So we expect these to be working in synchrony with each other.
But look at those atrium, they're not really contributing anything.
So this is why the patient, if they are awake, may feel dizzy, short of breath, or have chest pain.
Now I know this seems weird, but I've had patients talking to me when they go in and out of V tach.
It is really a strange experience, but if that V tach is sustained, the patient will likely lose consciousness.
Now the V tach can last a few seconds or it can lead to V fib and asystole, which is sudden cardiac arrest.
So anyone ever sees V tach come up on the monitor, everyone is running into that patient's room to check on them.
Earlier, you used pause and recall to remember what normal sinus rhythm look like,
and then compare it to ventricular tachycardia. Now, I'm putting them right next to each other.
So start with just looking at the top half of the heart compare in a normal and ventricular tachycardia.
Then start looking at the bottom half of the heart.
Yeah, the reason we're taking so much time with you
to make sure that you understand these concepts is this is the key to interpreting ECG strips accurately.
Knowing what's going on in the heart will help you recognize it on the ECG.
We have these seven steps.
So we've gone into detail in our previous videos, but we have them here again as a reminder.
So let's do a quick review of how to analyze any strip. Step 1: You analyze the heart rate and rhythm.
Remember you're making sure that you have the same equidistance between the R waves of the QRS and the P waves.
So they should plot along equally. P wave to P wave to P wave. R wave to R wave to R wave.
The next step is to analyze the P waves. You should have one P wave for every QRS.
They should all look the same and they should measure out equally. Third step is to measure the PR interval.
You're going to measure from right where that P wave starts to leave the isolectric line
down to where it starts to deep down again that is the PR interval.
Now, step 4 is measure the QRS duration. So you're going to measure how wide the QRS is.
Step 5: Take a look at the ST segment. Step 6: Look at the T wave.
We want to make sure that it isn't depress or elevated. And then step 7 we're going measure the QT interval.
So, ready? Let's go for it. Let's try and assess step one the heart rate and rhythm.
Now normally, we would count the QRS complexes and multiply 10 for a 6-second strip to calculate the beats per minute.
I want you to try and do that on this strip. But remember, pause the video, count them yourself,
and then we'll bring the answer up when you restart the video.
Okay, now, did you wonder where to count? Well, the deal here is only the ventricular rate is visible.
So you count those and multiply them by 10 and that tells you the rate of this particular strip.
So how did you do?
Did your answer match with the one we're showing you? Well, the rate is usually between 100 and 250 beats a minute in V tach.
That's really fast. So we're looking at the rhythm, is it regular?
Well, we've got the calipers up there to show you that you can measure that.
So measure on that strip, do you count in between each one?
Do these appear to be regular?
Now looking at the P wave right, not really possible, is it?
All we have is the ventricular activity, we can't see the P waves. This is a chaotic ventricular dysrhythmia.
So when we're looking at this overall and analyzing sinus rhythm,
compared to V tach, look that in a P wave and normal sinus rhythm,
they'll be there and they'll be before every QRS complex.
In V tach, P waves are not visible. The rhythm is regular in sinus rhythm.
And in V tach, the ventricular rhythm may be regular, but the heart is not pumping blood efficiently.
The rate for sinus rhythm is slower. The rate is much higher, usually in V tach.
Okay now, this is again, one of our charts, you know our strategy,
it would be best for you to really get this into your long term memory to cover up all six boxes,
see if you can recall from information in your own brain, and then check your answers.
Cover back up again and go to another box.
The more you use that strategy of recalling from your own brain,
not from just looking at notes, you're going to be even better at interpreting ECGs.
So measure the PR interval, well, we kind of let that one out of the bag, right?
If there's no P wave, we can't measure a PR interval. There are no discernible P waves on a V tach strip.
What about the QRS duration?
What would you expect just by visually looking at this? Yeah, it's usually pretty bizarre.
This is greater than 0.12 seconds, it will typically look like that, and looking at the ST, again, not possible.
Right? All we're really seeing is a ventricular action. So we can't look at the T wave either in step six.
And so therefore, we can't measure the QT interval in step seven. Remember, we can just see on an ECG strip the ventricular activity.
So let's take a look at the ECG criteria for V tach. Like you're thinking, do we really need to?
It's kind of an obvious strip, you always want to be systematic and methodical.
So technically, the definition for ECG criteria-for ventricular tachycardia
is greater than or equal to three consecutive ventricular beats known as PVCs.
And the rate should be about between 100 and 250.
Now when I started as a baby nurse, I took this very literally, because that's what the textbook says.
However, there are lots of patients that walk around, during multiple PVCs,
or we may be aware that that's happened or we're not going to treat it
but I didn't really consider that as a new nurse. So I made it my mission to run strips for everybody.
It didn't take very long before I wasn't allowed to sit by the monitor anymore.
So no, that's a textbook definition but we don't necessarily need to document.
If this is normal for the patient, they've lived like this, they're doing fine, or we don't plan to treat it.
So V tach with a rate of 100 to 120 a minute can be referred to as slow ventricular tachycardia.
I don't want to experience either, but ventricular tachycardia
with a rate greater than 250 can be referred to as ventricular flutter.
Listen, at the end of the day, this is V tach and it gets everybody's attention.
This is a life threatening dysrhythmia that can devolve to a really bad outcome fairly quickly, or just resolve on its own.
Now the QRS duration, remember, it's kind of big and wide and bizarre, and that's easy to see.
You might not know exactly what theQRS duration by eyeballing it,
but you know, it's not normal and you know, it's larger than normal.
So, let's wrap this up by reviewing why this particular strip is ventricular tachycardia.
Heart rate, zoom, real fast.
Rhythm, oh, it's regular, but it's not really helpful or productive.
P wave, uh-huh can't see them, they're not discernible. You don't see a P wave before the QRS.
Remember, this is just a ventricle problem and it's chaos.
PR interval, well, if we don't have a P wave, we can't measure a PR interval.
And the QRS is wide and bizarre. It's greater than 0.12, which is the normal range.
Thank you for watching this part of our video series.