00:01
Occasionally, beats will actually -- extra beats will actually develop in the AV node itself.
00:07
These are so-called 'nodal extra systoles'. They also have a narrow QRS
but there's no abnormal P wave before the abnormal beat.
00:17
They originate in the upper AV nodal region.
00:20
They're not very common. Much more common are atrial premature beats.
00:24
And here we see some examples.
00:26
You'll notice that the first three marked with an arrow have no P waves before the extra systoles.
00:36
So, you'll notice first beat, there's no P wave in front of it.
00:39
Then when we have a normal beat. The second beat, P wave, QRS, and T.
00:43
There's another beat there, no P wave. Then the fourth beat, P wave, QRS, and T.
00:49
And there's another extra beat with no P wave and so forth. It continues through out.
00:54
So, these without a P wave are nodal extra systoles.