![Shocked :shock:](./images/smilies/icon_eek.gif)
Thankfully, I am only 2 miles from a major clinic that brings in specialists. I had a heart ultrasound done on him. He has a leaky value, which in of itself is not a big problem, but he also now has an enlarged heart, which make it more serious. The change in the noise came from tearing off a 'leaflet' or something like that, so the noise is not the issue.
The cardiologist said that unless I did a riding ECG she could not guarantee my safety to ride him. That is because if he gets an arrhythmia while working, then it could be dangerous. I did the riding ECG on one of the hot and humid days. It was hard because I had to work him at least as hard as a normal ride. Fortunately, his heart beat stayed normal and I have the green light to keep working for about a year at which time I need to do both the ultrasound and ECG again ($750).
I had never had my horse's heart checked since his PPE. Had it not been for the vet last year and especially the dentist, I would have been clueless about the severity of this issue. Therefore, I would recommend that all those with old horses (and even young ones) get the heart checked routinely. You just never know. Lots of racehorses get Afib when they are young, so it is not just old horses.