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Module title = Tutorial: Analyze the Waveforms
Lesson title = How many P waves?
This is lesson 7 of 11 in this module
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.
What do you think about this example?
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.
How about this ECG?
It has 2 P waves (blue arrows) and 7 QRS's. The red arrows point to T waves.
Now it is your turn. Go practice. This skill is a little bit challenging, so some people might get frustrated.
Lesson 7 of 11
That was the last lesson!