Don't forget to add heart supporting supplements like: calcium/magnesium/potassium and vitamin e. Iodine would be good too, ditto C and a healthy dose of cod liver oil for d & a and efa's.
Don't despair. The heart can heal itself. I remember when my cat was diagnosed with hypertrophic cardiomyopathy. I was a wreck, even at work. The vet wanted me to put him on Hill's HD and didn't know diddly squat about supportive supplements for the heart. I took out my copy of The Natural Cat and worked up a diet from the book and tweaked her vitamix powder and added co-q10. My cat, then age 7, lived to be 18.
Post over to Natural Healing and see if uniy would recommend cayenne to his diet. I know cayenne is good for the heart too.