Anyone Have Experience With Cardiac Disease in Cats?

My 2 yr old cat recently developed an infrequent cough, I brought him to the vet to be checked out. We did bloodwork and some x-rays. The bloodwork showed no significant findings but the x-rays showed a heart that looks like it belongs to a cat 7 times his age. The vet is recommending an ultrasound and an ECG as further screening but wanted to know if anyone has any perience with cardiac disease in cats