Cardiac Monitoring Leads and Electrocardiography (Nursing)

00:01 So first of all, let's talk about putting this on the patient.

00:04 When you put on a cardiac monitor lead, we say right arm, left arm, V1, right leg, left leg.

00:10 See those in the picture there? Cool.

00:13 Now let's kind of help show what's going on in the heart because think of this as we're filming a movie.

00:21 And each one of these is a type of camera that has a different angle on the set.

00:26 Same thing with cardiac monitoring leads.

00:27 We've got five different angles on looking at how the electrical impulses traveling through the heart.

00:34 That's really what the leads do.

00:37 Now we can change on the different leads, lead II.

00:40 When you change the leads, the wave is going to start looking different.

00:43 We'll get to that later.

00:45 Just know for now, that by changing the different leads, it just means we're looking at the heart from a different perspective.

00:52 Or we're looking at with this cardiac monitor is the electrical activity.

00:57 Now some people remember, white on right, snow over trees and smoke over fire.

01:03 That's because of those are the colors of the leads.

01:06 The white on right.

01:09 Snow is white. Trees are green. Smoke is Gray. Fire is red.

01:13 So if you want to remember white on the right.

01:15 Snow over trees, smoke over fire.

01:18 That's just an easy way to remember where you put the right arm, left arm, V1, right leg and left leg lead based on colors.

01:28 Now let's start talking about electrocardiography.

01:31 You see, there's no reason for you to cry, like I did.

01:34 You already know far more about the electro conductive system of the heart than I did when I was taking the dysrhythmia course.

01:42 But look what we have done for you.

01:45 This gets me so excited when I see how they've broken this down.

01:48 It's so simple.

01:50 Okay, SA node.

01:52 Hello, old friend.

01:53 We recognize that one, right? We know what that is.

01:56 So we're talking about Depolarization.

01:58 That's what sends the signal through and causes the muscle to contract.

02:03 So what you're looking at, see how it's purple there and see the P wave.

02:08 Okay, all...

02:11 This is so simple, it's hard to even to not get excited even more when I tell you.

02:15 All a P wave is, is showing us the depolarization of the atria.

02:22 So it's initiated by the SA node, and it causes the P wave.

02:26 So see how they've got purple at the top for you.

02:29 That represents the depolarization Look at the P wave in purple.

02:33 Okay, cool.

02:34 So you know what I can learn about a patient's SA node with all the P waves look the same? They're all perfectly spaced.

02:42 They have the same length between those and the next wave, they match.

02:46 And I have one P wave for every QRS, I know all is well with the SA node.

02:52 So when you're looking at a strip, Now, this is lead II by the way.

02:56 Just so you know what lead we're in.

02:57 You might want to write a little roman numeral II up there to remind you.

03:01 The P wave represents the depolarization of the atria.

03:06 Okay, so you already knew how the signal travels.

03:09 Now you know what it looks like on a strip.

03:13 Now let's keep going.

03:15 Now you see the electrical impulse is delayed at the AV node.

03:19 What? Why would the AV node slow things down? Well, your heart's going to work better if it does this: Atrium, ventricles, atrium, ventricles, atrium, ventricles, atrium, ventricles.

03:28 Okay.

03:29 It doesn't do so good if you go.

03:31 If they're both contracting at the same time, leads going to go all different ways.

03:36 I need a little bit of a delay.

03:38 So the valves work, right.

03:40 And blood keeps going in a forward motion and not getting just all crazy.

03:45 So that's why I need just a touch, just a skoosh of delay, at the AV node.

03:51 See how now you have the depolarization has moved down a little farther.

03:55 Cool.

03:57 Now, the atrium is going back to repolarizing.

04:00 Its resting.

04:01 But now look where the purple has moved.

04:03 It's now the QRS part of an electrocardiography.

04:08 So see that? QRS is all in purple.

04:11 Now look at the purple on the drawing.

04:14 Okay, that's the ventricular depolarization begins the QRS complex.

04:20 Q-R-S.

04:23 Yeah, I promise it's that simple.

04:25 As well as the atrial repolarization.

04:27 Now we can't really see the atrial repolarization in there.

04:32 But trust me it is.

04:33 That's why it shaded the lovely shade of green in there.

04:37 And the purple is focusing on what's making the wave.

04:40 That's what's happening and to make the QRS.

04:45 Now, hey, what if that QRS and lead II we expect it all to be pointing up in lead II.

04:51 So if it looks like this wow, it's QRS.

04:54 It's got that nice look, it's not too wide or bizarre.

04:58 That tells me that all is well.

05:00 That things are moving through the ventricle and it's the electrical impulse is passing adequately.

05:06 And if we're getting a good heartbeat, everything should be as normal in that hearts electrical system.

05:13 Now when the ventricular depolarization is complete, look what we have there.

05:18 See it? Okay, so now you see where the purple is.

05:21 That's the depolarization.

05:23 We're going to look for repolarization.

05:25 So there you see it.

05:27 Now you see where it's green.

05:28 That's the T wave.

05:30 Okay, so the T wave is when the ventricle is resetting itself.

05:35 Now, lets gets super fancy when we're looking at MIs, we look at STEMIs or non- STEMIs, that is ST, that area between the S and the T.

05:44 ST segment elevated MI is the most serious MI.

05:50 You'll be able to tell that when you look at electrocardiograms.

05:54 When you look at an EKG, you'll be able to see ST segment elevation, But for now, you're looking for that to say, "Hey, is everything resetting normally?" "Is everything, okay?" In the future, you'll watch for that to either be depressed, like it could be in ischemia or we've got elevation because it's there because the patient is having a really serious heart attack.

06:17 Focus on what you see is going on in the heart right now during repolarization.

06:22 That's what represents the T wave.

06:26 All right, pretty cool.

06:27 Everything is complete.

06:29 Repolarization is All complete.

06:32 And now we've walked you all the way through one heartbeat.

06:36 P wave, QRS, to the T resetting.