EKG Changes In Athletes?

May 19, 2011 3:28 AM

I need help. Can someone provide a really, really non-smarty pants explanation of how the conduction through the heart changes for athletes (EKG) -- with an emphasis on 1st AV block.

I've googled this topic but I'm confused. I was hoping someone can provide an easier to understand explanation.

Thank you!

posted by learninguntilidie to Science & Nature (2 answers total)

Response by poster: I omitted the word degree, it should read: "1st degree AV block"
posted by learninguntilidie at 3:33 AM on May 19, 2011

Best answer: In general, athletes' hearts undergo some degree of remodeling, ie, they become more muscular, certain chambers are enlarged, etc. With these remodeling changes come changes in the conduction of electrical impulses through the heart. As the heart gets bigger, say, the conduction pathways are also modified, and it takes longer for the impulse to reach the ventricles from the SA node, which leads to a 1st degree AV block, which is almost always a benign condition, even in non-athletes. There are a few EKG changes that you can see in highly conditioned athletes that can mimic serious or potentially serious problems in non-conditioned people. First degree AV block is one, as well as sinus bradycardia (heart rate less than 60 but with a normal sinus presentation), increased amplitude of the QRS complex, etc. "Normal" EKG parameters are based on typical hearts, so when the heart itself undergoes changes because of increased demands placed on it, from conditioning or, conversely, pathological conditions like heart failure, it causes changes in how the typical conduction system works and how it appears on an EKG. This is why it's often possible to tell what areas of the conduction system are damaged or which chambers of the heart are abnormal based on the EKG.

That was a relatively simple explanation, I think...I hope it wasn't too smarty-pants.
posted by doogan nash at 4:02 AM on May 19, 2011 [7 favorites]