Heart disease in dogs?

[nixy_nooh]

My Rough Collie, Sandy, seems to be showing signs of heart disease. He's slow, although there appears to be no aches or pains in his joints, apart from a slight spine arthritis that isn't really stopping him, He has sudden bursts of energy where he will run round in circles like a lunatic for a couple of minutes, then he will stop and start coughing his head off. He has also began panting a lot more than usual, even when its not very warm out. He was also diagnosed with a heart murmur by his vet when he was four years old, and he is now eight years old. DO you think he has heart disease? Should we get him checked out? Thanks
Also, what treatment would the vet give Sandy, and can heart disease be cured?