Treatment of Paroxysmal Supraventricular Tachycardia (Nursing)

00:01 Now let's talk about that vagus nerve is kind of a cool thing, isn't it? I remember one time I was with my brother and my dad.

00:08 And something was so funny.

00:10 I don't even remember what it was.

00:12 But I was laughing so hard, I passed out, you know what happened? Well, I stimulated my vagus nerve.

00:21 I was out for just a second.

00:22 But when I came back, I was a little woozy.

00:26 Because the vagus nerve controls the parasympathetic response of the heart.

00:31 So stimulation of the vagus nerve will lower the heart rate.

00:34 In mine, it lowered it all the way down.

00:38 Now in healthy people, parasympathetic tone from these sources are well matched to the sympathetic tone so it doesn't usually cause a problem.

00:46 But hyperstimulation of a parasympathetic influence promotes some Bradyarrhythmias, that's what happened to me.

00:55 I went all the way out.

00:57 But the minute I went out, my body kicked in, that sympathetic stimulation kicked in, and I was right back with the world.

01:05 But when it's hyperstimulated, the left vagal branch predisposes the heart to conduction block, right at the atrioventricular node.

01:14 I remember that the we've also called that AV node.

01:18 So should this be a problem without hyperstimulation? No.

01:22 And if the person is relatively healthy, then they've got a good balance between their parasympathetic which is, you know, think of that, like after you've had a big thanksgiving meal, you're moving kind of slow, versus the sympathetic, which is that fight or flight, when you're all fired up.

01:40 There's usually a balance because our bodies are amazing.

01:45 But if that vagus nerve is hyperstimulated, your heart is going to slow way down, which is why it can sometimes be helpful with supraventricular tachycardia.

01:58 Now you've got a right and a left vagus, the right vagus nerve innervates the sinoatrial node, which is going to give you a very slow heart rate.

02:09 Before we go on, stop for just a minute and look at this drawing.

02:14 Now I know we're talking about the vagus nerve, you see those beautiful golden nerves, right? Right down there that the artists have created for you.

02:22 But stopping orient yourself to a picture.

02:25 Don't waste these beautiful pictures for helping you keep oriented and learning in more detail.

02:33 So look at everything that they have labeled for you, look for your trachea, look for the esophagus, where are the carotid arteries? Look at the other words, and make sure that you understand what those structures do in your body.

02:49 Yes, I know we're looking at ECGs and we're talking about SVT, and vagus nerves, but you can always reinforce information that you already have in your brain.

02:59 And that is a winner winner chicken dinner, as we say around my house, because you're using this as a form of spaced repetition and you're studying.

03:09 Anytime you do that, you're telling your brain, "We've got this, we've got this, we've got this." And the more you make connections between information, exams are going to be much more successful for you.

03:21 But even more important is you're going to be able to be a proficient and safe nurse.

03:27 So how do we stimulate the vagus nerve? Well, you do the valsalva maneuver.

03:32 This is what you do, you follow the steps in order.

03:34 So you could pinch your nose closed, close your mouth, and try to exhale as if you were trying to inflate a balloon like this.

03:44 I don't think you're doing this with me.

03:45 So I'm going to need you to really experience this.

03:49 So pinch your nose, close your mouth and try to exhale.

03:54 It's what a lot of us do when we're on an airplane and our ear feels like it's popping.

03:59 That's one way to do the valsalva maneuver.

04:02 Now, here's another way it's not so socially acceptable, but you're going to bear down as if you're having a bowel movement.

04:09 Now, be careful. I don't want to know what else happens in there.

04:11 But you want to do that for about 10 to 15 seconds, that will also stimulate that nerve.

04:18 So let's talk about the treatment of PSVT.

04:21 I'm going to focus specifically here on medication.

04:25 Now we've talked about the valsalva maneuver or we're stimulating the vagus nerve, those aren't medications.

04:32 What I want to talk about here are two types of medications.

04:36 One category is an antiarrhythmic agent.

04:39 The other category is a calcium channel blocker.

04:42 So let's go through an antiarrhythmic agent column first.

04:45 Name of the medication is Adenosine IV.

04:48 Now it takes just under two minutes to convert the patient out of PSVT.

04:54 What's our conversion rate? Hey, that's like a mid-range B 86.5%, that's pretty good.

05:01 Now what's the likelihood that the patient who's received adenosine might relapse into SVT? Well, it possibly you say the words they're possibly more common.

05:13 Could we be more vague than that? Well, it is not unusual for someone to relapse into SVT after being treated with adenosine.

05:23 Now, the side effects.

05:24 This is not fun for the patient.

05:26 They usually don't like receiving this medication, because they get chest pain, flushing, it's really uncomfortable for them.

05:34 Now a kinder gentler option could be a calcium channel blocker.

05:39 Now that might be Verapamil IV or diltiazem IV, but it's going to take a little longer for that PSVT to convert.

05:47 Remember, adenosine was under 2 minutes.

05:50 Calcium channel blockers is about 6.5 minutes.

05:54 But look at the conversion rate.

05:57 Yeah, it's 98%.

05:59 Now we think that compared to adenosine, they're less likely to relapse into SVT.

06:06 Now they can also have some hypotension.

06:08 Remember, anytime you give a medication, you have the risk of a side effect.

06:12 But practitioners will be looking at the risks and benefits of both of these groups of medications and see which one is more appropriate.

06:22 It would depend on the severity of the PSVT, how often they're having, but most people would prefer the experience of a calcium channel blocker over adenosine just speaking as a patient receiving that how they feel.

06:39 Now here's one important caveat, as we say, Wolff-Parkinson-White or WPW and medications.

06:48 Because both of the medications we just discussed like the adenosine or the calcium channel blocker, both of those groups of medications are contraindicated, meaning you should not give those medications to a patient who has a diagnosis of WPW.

07:05 Now that's a pre-excitation syndrome.

07:08 So Wolff-Parkinson-White or WPW is a pre-excitation syndrome.

07:15 That means it has a really short PR, it's delta wave, got some polymorphic atrial fibrillation.

07:21 At this point, you're saying, "What are you saying?" Well, I'd really focus on this got that super short PR.

07:28 And this can be problematic for a patient who has Wolf-Parkinson-White to receive adenosine or calcium channel blockers.

07:39 We'll talk more about Wolff-Parkinson-White in a future presentation.

07:43 But either one of these medications in WPW can lead to yeah, ventricular fibrillation.

07:53 That is a life-threatening, life ending dysrhythmia if we don't treat it effectively, and quickly.

08:01 Look at what's going on in our graphic.

08:04 How does that appear different to you from what we saw in sinus rhythm? So let's wrap up why this is PSVT.

08:14 So you look at the heart rate, overall it's over 100.

08:18 The rhythm is regular but you can see this reason it is shortened.

08:24 Now the P wave.

08:26 Yeah, you can measure it before the sinus beats, but you can't measure it where it kicks into PSVT.

08:33 Now the PR interval.

08:35 Again, I can measure that for the sinus beats, but I cannot measure it where it's PSVT.

08:41 QRS is even the sinus beats and the PSVT beats are within normal range less than 0.12.

08:50 Thank you for watching this part of our video series.