Okay. In this video, we are going to talk about
junctional rhythms. So if you recall, we have the SA node or sinus
node. And if that fails, then the atrial foci take
over. And if that fails, then the junctional foci
in the AV junction take over. The inherent rate of a junctional rhythm is
a little slower, so it's between 40 and 60 beats per minute. And the key characteristic of a junctional
rhythm is that the P wave is messed up. It's either absent, it's inverted, it happens
after the QRS complex instead of before, or we have a very short PR interval. So you'll definitely want to be looking for
those things to be able to identify a rhythm as junctional. So in this video, we will talk about a junctional
rhythm, a junctional bradycardia rhythm, an accelerated junctional rhythm, as well as
a junctional tachycardia rhythm. Okay, here we are looking at a junctional
rhythm. So if we first assess the regularity of this
strip, we will see that it's actually very regular. We have equal distance between our R waves. Our P waves are messed up. You can see they're inverted as opposed to
upright and smooth. However, we have an equal distance between
those P waves. So both the ventricular and atrial heart rhythms
are regular. If we calculate the heart rate, so because
we we are dealing with a regular strip. We can use the small box method to do this. So we have approximately 34 small boxes between
these R waves. So if I take 1,500, divide it by 34, I get
44 beats per minute, which is right in that range we talked about with junctional rhythms,
right? Junctional rhythms will have an inherent rate
between 40 and 60 beats per minute. And if we look at the different components,
like we said, the P wave is inverted. That is not normal. That's our other big clue that this is a junctional
rhythm. Our QRS complex is nice and narrow, so that's
how we know we're not dealing with a ventricular rhythm. So this is a junctional rhythm strip. Treatment of a junctional rhythm is typically
not necessary. However, if the heart rate is too slow to
maintain adequate cardiac output, then atropine can be used to increase the heart rate. The other thing you should keep in mind is
you want to avoid the use of digoxin in patients with junctional dysrhythmias. And in fact, digoxin toxicity is one of the
most common causes of junctional rhythms. So you definitely have to be careful with
digoxin. Okay. Now we are looking at a junctional bradycardia
strip. So again, we have a regular strip. And if we calculate the heart rate between
these R waves, there are 46 small boxes between the R waves. If we take 1,500 divided by 46, we get 33
beats per minute. So this is a very slow rhythm that is regular. Again, we're looking at a junctional rhythm
because it's slow and because we have this messed-up P wave again. It's inverted here as well. QRS complex is nice and narrow, under three
small boxes wide. So with junctional bradycardia, the heart
rate is under 40 beats per minute. So in this case, we have 33 beats per minute. So that fits the bill here, and that's how
we know we are looking at a junctional bradycardia strip. So in terms of treatment, again, like I shared
with the last strip, if the heart rate is too slow to maintain adequate cardiac output,
then the patient may need to be given atropine to increase that heart rate. And again, we're definitely to want to watch
digoxin, because digoxin toxicity can lead to junctional rhythms such as this. Okay, now we are looking at an accelerated
junctional rhythm. So again, the strip is regular. We have equal distance between our R waves,
but we can see that we are missing our P waves, which is one of the things that will happen
when you have a junctional rhythm. So we know this isn't normal sinus rhythm
because we're missing these P waves. So let's look at the rate. If we count the number of small boxes between
the R waves, we will see that there are approximately 18. If we take 1,500, divided by 18, we get 83
beats a minute. So we know it's not junctional rhythm because
the inherent rate of junctional rhythm is between 40 and 60 beats per minute, so it's
a little faster than that. So with accelerated junctional rhythms, we
can expect a heart rate between 60 and 100 beats per minute, which is the same range
we see with normal sinus rhythm, but again, we're missing the P wave, and that's why we
don't have normal sinus rhythm here. Okay. We are finally looking at a junctional tachycardia
strip. So we can see that it's a very regular strip,
but it's very fast. So since we're dealing with a regular rhythm,
we can do the small box method to calculate the heart rate. We have approximately 13 small boxes between
R waves. So if we take 1,500, divide it by 13, we get
115 beats per minute. So it's definitely a tachycardia. It's not sinus tachycardia because we don't
have this P wave. We just have this little flat line where the
P wave should be. So it is a junctional rhythm. But with a normal junctional rhythm, the inherent
heart rate should be between 40 and 60. With accelerated, it's between 60 and 100. With junctional tachycardia, the heart rate
will be over 100. So in this case, we have approximately 115
beats per minute, so that fits the bill for junctional tachycardia. So we have normal QRS too, just to point that
out, because when we move into my next video, which will talk about ventricular rhythms,
we'll notice that this QRS will get wide. So stay tuned, and we'll get through the rest
of these dysrhythmias. Thanks for watching!
