Eccentric hypertrophy of the left ventricle. Thickened mitralis valves with prolaps of posterior leaflet.
I think blood culture should be done (since the dog has pyrexia of unknown origin)
For the frontlimb lameness I would be worried about a tromboembolie. I would measure glucose level central (v. jugularis) and periferal (in this limb) to see if there is a difference which is suggestive of embolus.
