EKG of the Week
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+ EKG Interpretation
Dr. Ohlbaum's Explanation
This "new" EKG is a bit tricky, and we have an old one, so let's start by looking at the old one.
At first glance, the ventricular complexes (QRS's) are narrow but occur irregularly. For most of the EKG there are clear atrial flutter waves and irregular conduction pattern so it is atrial flutter with variable block though there are also some areas with more chaotic (not perfectly marching out flutters) atrial activity. I would call that afib-flutter and there is an overall fast rate. The QRS's are narrow, there are no Q's. The ST's are somewhat obscured by the flutter waves but even allowing for that they are a bit saggy in many leads so a nonspecific ST abn.
So, overall reading: afib/flutter with rapid rate and nonspecific ST abnormalities.
Ok, so with that in the back of our minds let"s look at the "new" EKG. It is still irregular and there are no p waves or flutter waves so atrial fibrillation makes sense. But what has happened to the QRS? It is MUCH wider. The shape looks similar in every lead, just stretched out a lot wider. But it does not really fit a right or a left BBB. And then, what do you think of the T's? They are very big and come to a point at the top.
Remember what happens with hyperkalemia. I think about K+ as living under the T. So as the potassium goes up the first thing we see is a big and PEAKED T wave. We usually see that when K+ is in high 6's. As the K+ continues to rise the T continues to get bigger and the P wave starts to disappear. This patient in afib/flutter to begin with so no P to lose (though I wonder if that is why we don't see a flutter wave).
It's easy to imagine the potassium pulling on the T wave making it pointy. As it continues to pull, the QRS widens and finally the PR prolongs.
As the K+ continues to climb the QRS starts to widen out. Eventually the QRS is so wide and the T's big and pointy we are looking at a sine wave.
This ekg is showing hyperkalemia in a patient with acute renal failure and a K+ of 9.2.
