ECG Level 1 Tutorial: Analyze the Waveforms
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Tutorial: Analyze the Waveforms
This module will teach the basic waveforms on ECG and a stepwise approach of how to analyze them. Practice each step and get feedback on your performance.
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Tutorial: Analyze the Waveforms How many P waves?
Lessons
42
Times Practiced
1284
Cases Completed
1h 24m
Total Time spent
1m 24s
Average Time
Progress
Accuracy
Efficiency
Accuracy
Efficiency
1 Anatomy Anatomy
2 Waveform Identification Waveform Identification
3 Waveform Identification #2 Waveform Identification #2
4 Determine the heart rate Determine the heart rate
5 Do you have Rhythm? Do you have Rhythm?
6 P waves! Where are you? P waves! Where are you?
Current lesson 7 How many P waves? How many P waves?
8 P wave Size and Shape P wave Size and Shape
9 PR Interval PR Interval
10 P conducted to QRS? P conducted to QRS?
11 QRS Width QRS Width
How many P waves?
This lesson will focus on the ratio of P waves to QRS's.

When there are more P waves:
  • some P waves are not getting conducted to the ventricles due to conduction block in the AV node

When there are more QRS's:
  • a QRS is being generated but no P wave is being generated
  • this occurs when the AV node or the ventricles generate the QRS

For the following ECG's:
  • count all the P waves
  • count all the QRS complexes
  • if not equal, then find the extra or missing items

In this example, we have 7 P waves and 5 QRS's. Therefore, there are more P waves and in this example, it is due to a conduction block. Blue ovals indicate the missing QRS complexes.
P wave without a QRS

What do you think about this example?
Lots of P waves
Crazy, all those skinny little P waves! Did you count 16 and only 4 QRS's, so there are WAY more P waves than QRS complexes. When this happens, there is a conduction block (in the AV node) which we will teach you about later.

P waves are usually very regular. Thus we should expect a P wave where the red arrow is. This P wave is not visible because the QRS is superimposed on the P wave, making it virtually impossible to see him. Poor little guy; it's just not fair sometimes. The T waves are not readily seen in this ECG. Sometimes, T waves or P waves do not show up in every lead.
regular P waves

How about this ECG?
only 2 P waves

It has 2 P waves (blue arrows) and 7 QRS's. The red arrows point to T waves.
2 P waves

Now it is your turn. Go practice. This skill is a little bit challenging, so some people might get frustrated.