Jerry_NJ, wow, that is tall! Here I thought the guy next to you in your profile pic was short :-)
jeric, R on T is shorthand for the timing of a PVC. It means that a PVC occurs during the T wave. In English, it means the ventricles trigger a ventricular beat while the ventricles are recovering from a previous beat. The T wave is when the ventricles are "repolarizing". Think of it as the muscle is recharging itself to get ready for the next beat. So, R on T basically means that a ventricular beat is fired while the muscle is trying to recharge itself. There’s some theory around the implications of this hence why it has its own name.
Another interesting point about the differences between the atria and the ventricles is the T wave itself. When the atria are in recovery (repolarizing) there's no discernable wave detected (that I'm aware of). Not so with the ventricles. There's so much more muscle mass there that when the ventricles repolarize there's a detectable electric wave called the "T wave". The T wave is *usually* larger than the wave produced by the atria when they are actually contracting! The basics of the ECG are this: SA node fires causing the atria to contract - small P wave - this goes to the AV node hitting the ventricles causing them to contract - That's the big QRS wave - then the ventricles produce the T wave during recovery. That's the major points to it. The heart is a beautiful machine when it works right.
Maybe I'll just sit......:)
I was told years ago by a cardiologist that a percentage (I'm thinking he said 20%) of the population has irregular heart beats at any one time, and it's not always the same 20 percent.
So is a thinner atrial wall better or worse? I was told the septum between the atria was thickening.
Yes, I have read/heard that extreme athletes and tall people have a higher than average incidence - I am 6' 6" (that's tall) and was a runner (but not extreme) long before I was diagnosed with AFib.
You're probably right about enlargement/irritation. The atrial muscle walls are much thinner than the ventricles. It all has to do with stroke volume. I think some of the gains in stroke volume that athletes get is attained through muscle stretch, from what I’ve read over the years. Again I'm thinking along the lines of "too much of a good thing".
Yes, that's interesting. Seems moderate exercise is good for body and mind, but athletes actually strain their hearts which may cause arrhythmias.
I had a theory that the right atrium was going "front line" in receiving all the blood from the veins that returns during exercise and high cardiac output, and got dilated or irritated, but that's probably not correct..
Interesting how trained hearts had a significantly higher rate of PACs. I've anecdotally read that hyper trained athletes have a higher incidence of a-fib as-well. The atria don’t seem to like all that work. To me this is further evidence that "everything in moderation". Too much (or too little) of anything can lead to unexpected results.
Thanks for sharing that is encouraging. :)