+ EKG Interpretation
Dr. Ohlbaum's Explanation
This is an interesting rhythm.
If you ask our usual questions: is it regular or irregular, narrow or wide, fast or slow, p's or flutters, you notice that there are not simple answers to any of those questions!
You notice that there are 2 very different QRS complexes. Every other beat is narrow (start with the 2nd complex on the page) and the distance between that beat and one before is very irregular. The other beats are wide but the intervals between the narrow and wide ones are mostly the same (one of them is a bit off).
There are no P waves, but in some stretches (look at Vl near the end) there are clear flutter waves. How can we put this all together?
The underlying rhythm (the atrial mechanism) is atrial fib-flutter (he is back and forth between those, and that is not new). But then, there are PVCs in a pattern of bigeminy (did you know that happens in afib as well as sinus?). When the R-R is from the afib the interval is very irregular, when it is from the PVCs it is nearly regular. And there are 2 different morphologies.
When we look at the QRS morphology, we only want to look at the narrow complexes (those coming from the afib) since the others are ventricular beats. Those complexes are about 100 msecs but look like a RBBB, so there is an incomplete RBBB.
So, this is afib-flutter, with PVCs in a pattern of bigeminy and an incomplete RBBB.