Cardiomyopathy is a serious condition and the best advice is to seek out a qualified medical professional well versed in naturopathy.
Oxygen could help - either the H202 or the product I sometimes use and prefer - OxyGen, which has he equivalent oxygen as 12 drops of 35% food grade H2O2 in each capsule. So could colloidal silver since cardiomyopathy often has a viral cause.
Also important for heart health are:
Magnesium (supplemented 1 to 2 with calcium)
Iodine with it's important co-factor selenium
Hawthorne berry syrup (I like Dr. Christophers)
Though widely available, CZ sponsor Utopia Silver has all of those items and a discount code for CZ'ers of LR001 which gives a 15% discount to any items not currently on sale. Personally, I prefer the magnascent and SSKI iodine combo from Trapper, but the Lugols from Utopia Silver should work fine too.
I also note that building up the immune system is reported to be good for congestive heart conditions such as cardiomyopathy - and nothing does that as well as oleander extract and a good overall diet and lifestyle and an all around whole food nutrition product such as IntraMAX.