Dressy’s Arrhythmia

Dressy has always had a cardiac arrhythmia. It’s something called a second degree AV (atrioventricular) block. An AV block is not dangerous or any kind of a problem. It typically occurs in very fit, athletic horses with efficient hearts. It’s rather as if the heart works so well that it takes a bit of time off in between. An AV block still produces a regular heart beat pattern. It might be three beats/skip/three beats/skip, etc. Or it could be four beats/skip etc. But it’s regular. And the skip pause is exactly the time it would have taken to beat, so it’s right in rhythm. The skip goes away once she starts working.

When she first started competing a few years ago, I got a letter from the vet documenting the AV block so that I could request “Stethoscope Only” heart rate checks, since a hand held monitor (known as a ‘wand’) can be inaccurate with arrhythmias.

What Dressy has now though is quite different. Her heart beat has become very chaotic. There’s no pattern. Some beats are louder, some quieter. Sometimes you don’t hear a clear lub-dub. It speeds up, slows down, misses one beat, misses three beats.

I think, in hindsight, that this probably started at Aprilfest. Our final heart rate at the end of the 25 was 48. Which is quite high for Dressy. At the time I wrote it off to her being a bit tired. But Chrystal pointed out that she should not have been that tired. And she’s right. Dressy has a resting pulse of 28 at home. And it is not unusual for her to have 36 or 40 pulses in competition if she is given time to cool down. She did have 30 minutes. The last person to listen to her heart rate (a PR tech, not a vet), commented that it sounded odd (‘freaky’ was the word she actually used). I didn’t pay much attention, since I very often hear comments from techs at rides because of the AV block. But I guess I should have. I suspect that’s right when it all started.

We will find out tomorrow if what she has is Atrial Fibrillation. That’s the most likely diagnosis (and at this point is what I’m hoping for). It would be treated by restarting/shocking her heart back into a normal sinus rhythm. It’s a rather scary procedure, and there are some risks. Sometimes it takes several tries. But assuming she survives being dead, the prognosis is pretty good in most cases. She’d have a short recovery period and then could go right back to doing what she’s always done.

We will find out tomorrow what we are dealing with. If what she has is not AF, then things would likely not look nearly so good.

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