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 P conducted to QRS?
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?
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
Current lesson 10 P conducted to QRS? P conducted to QRS?
11 QRS Width QRS Width
P conducted to QRS?
Is the P wave "conducted" to the QRS? Very good question. In a normal heartbeat the answer is yes because the following events occur:

the electrical impulse is initiated by the SA node,
impulse starts at the SA node

is conducted through the atria,
conduction through the atria

down through the AV node,
conduction through the AV node

and conducted to the ventricles.
depolarization of the ventricles

Super important detail: the SA node is generating both the P wave and the QRS complex. When this happens, we say that the P wave is conducted to the QRS. 

When this happens, we will see on the ECG:
  • an upright P wave is present
  • the PR interval is normal length, or could be long
  • a QRS complex is present
  • the P wave occurs before the QRS
WHY these criteria are required?
  • when the SA node is the pacemaker, it immediately conducts into the atria and creates an upright P wave (as opposed to an inverted P wave)
  • the PR interval is created by the delay in the AV node
  • if the electrical system makes it down to the ventricles, then a QRS complex is also required
  • everything must happen in this order
Before you have learned about abnormal rhythms (which is now), you might be thinking that all these details are super obvious. However, there are rhythms with no P waves or P waves that come AFTER the QRS or missing QRS complexes or pretty much any combination of strangeness that you could imagine. Therefore, always look for the threesome of the: P wave, PR Interval, and QRS complex in that order. If any one of these is missing, something abnormal will be happening in the ECG.

This lesson might seem like a small detail, but it is a very important concept: we are dedicating an entire lesson on it. Try the practice sessions and see how you do.