Sinus Tachycardia (Nursing)

00:01 Hi, welcome to our video series on electrocardiogram.

00:05 In this one, we're going to look at the fast moving sinus tachycardia.

00:10 Now at this point, we all know this is a normal ECG but what if we shorten it like this? Would you consider it to be abnormal? Let's find out together in this course.

00:23 A normal P wave is an atrial contraction precedes every QRS complex in a normal sinus rhythm.

00:30 The rhythm is regular, but can vary slightly during respirations.

00:34 The rate ranges between 60 and 100 beats a minute, and the P wave is positive in lead I, lead II, and it's biphasic in lead V1.

00:45 So here are the seven steps we're going through in each of our videos.

00:49 If you need more help on this, go back to the first videos that will explain in detail each of these seven steps.

00:58 Once again, let's recap.

01:01 Remember, the electrical impulse travels from the atria to the ventricles and its trajectory is what gets documented on the ECG strip.

01:09 At first, the electrical impulse gets created at the SA node and starts traveling toward the AV node.

01:16 This causes contraction of the musculature of the atria and the formation of the P wave.

01:22 When the impulse reaches the AV node, it doesn't just pass through it, it gets delayed.

01:28 This delay is documented in the ECG strip as the PR segment.

01:33 So the PR segment corresponds to the passage of the impulse through the AV node.

01:40 Next, we have the QRS complex.

01:43 The QRS complex represents ventricular contraction, which is caused by the migration of the impulse from the AV node to the Purkinje fibers.

01:53 Moving on, we can see the T wave, which is caused by repolarization or relaxation of the ventricles.

02:00 And as previously mentioned, the interval between the ventricular depolarization and repolarization gets documented as the ST segment.

02:09 Finally, we have the U wave, which is believed to be the product of a delayed repolarization of the Purkinje fibers.

02:15 And remember, this wave may or may not be present on the ECG strip.

02:21 So let's walk through the seven steps with this ECG strip.

02:26 Step one is rate and rhythm.

02:29 So identify six seconds of a strip and count those QRS complexes.

02:36 Now, you want to make sure that the intervals in between the Rs are the same.

02:41 And so they're regular that will help us identify a regular rhythm.

02:45 So when we're assessing the rate, make sure you assess both the ventricular and the atrial rate.

02:52 Pause the video, count the rate on this slide and see what you get for the atrial and ventricular rate, and then compare your answer with the answer we display.

03:09 Now when you plot the R to R and from the P wave to P wave, is it regular and consistent? The answer is yes.

03:20 So let's take a look at those P waves.

03:23 Are there P waves present for each one of the QRS? Now don't just jump ahead, actually make yourself look to see that there's a P wave in front of every QRS.

03:35 Okay, they're all there and they look the same.

03:38 Now we've highlighted the P waves with a blue box here, just as a gentle reminder.

03:43 Now look at the P to P interval.

03:45 Is it regular? Yeah, excellent. Things are looking pretty good for us.

03:52 Now we're going to measure the PR interval.

03:55 Remember it should be .12 to .20 or 3 to 5 of those tiny boxes, because they represent .04 seconds apiece.

04:07 So pause the video and measure the PR interval on this strip.

04:12 When you're done, restart the video and compare your answer with the answer we will display.

04:25 Step four. Let's look at the QRS duration.

04:28 Now in a normal beat, we would expect it to be less than 0.12 or 3 tiny boxes.

04:37 Pause the video and what is the QRS duration on this strip so we're going to ask you to measure the QRS duration.

04:44 When you're done, restart the video and see if your answer compares to our answer.

04:54 Next, number five, look at the ST segment.

04:59 Do you see any depression or elevation? Remember that is not normal to see depression or elevation.

05:07 What do you see on this strip? Do you see depression or elevation in the ST segment? Right, the answer should be no.

05:18 Now we're going to look at the T wave.

05:21 Is it rounded? It looks pretty rounded to me because we do not want that to be peaked or tall.

05:28 That tells us we've got another problem.

05:30 So examining the T wave we're looking for, is it the same? Is it rounded? And is it not peaked? And is it not taller than normal? Looks like we're good to go on this rhythm strip.

05:47 Step seven, measure the QT interval.

05:50 Well, we have the normals up there for women and for men, I want you to pause the video and measure the QT interval.

06:03 Now that you've done that on your own, we're going to show you the answer.

06:08 So let's wrap up why this particular ECG strip is sinus tachycardia.

06:13 Heart rate, definitely greater than 100.

06:16 Rhythm, regular.

06:18 R to R to R to R, P to P to P to P, we're good.

06:24 Is there a P wave before each QRS? Absolutely, and they are identical PR interval, is it within .12 to .20? Yes.

06:36 And QRS, is it less than 0.12? Beautiful, we have a winner.

06:43 So thank you for watching this part of our video series.