How was this diagnosed, and does he see a cardiologist, I would think seeing a senior cardiologist would be my first port of call.
Husband at 59, GP or regular Dr said there was nothing wrong with him, but to me he was not as normal, I had to insist that he be seen by cardiologist.
How did I know, he needed a cardio Dr, I didn't realize until it was pointed out to me by nurse sister (sibling) that I had lived with a father with heart failure, he had it when I was born, and now my husband had developed the same, Dad's was from rheumatic fever, husbands from a virus or so they think, sister thinks I sub-conciously recognised the same even though Dad had died 40 years ago, before the modern drugs that are keeping my husband alive were available, husband also has a pacemaker and defibulator with three leads keeping his heart going, he has improved out of site since the pacemker installed.
My husband is only alive because of my strong demands, even junior cardiologists have dismissed subtle symptoms, husband does not get swollen ankles of most heart failure patients, but I can tell you when he is in trouble just by looking at him.
Educate yourself, ask lots of questions, hit the library, ask the local Dr for his cardiology books, and get an understanding of his condition, and then educate both of you, keep fit, husband walks 4 - 5 klm's a day, rides a stationery bike 3 - 4 times a day for 5 minutes at a time, doesn't allow himelf to get too breathless, has learnt to stop and take a breather, does his best to control weight, we have a dietitian available to us to help when we feel the need.
We are in Australia so we have universal health system thank god, because without it we would be in real trouble financially.
5 visits to heart hospital, each and every time life threatening in the last 5 years, last time, just a couple of weeks ago he caught a virus, and he got really sick, blood in urine, liver function tests extremly high, platelets collapsed, on the verge of giving him platelets transfusion, when his bloods came back from lab as improving, heart hospital kept him for 5 days, and then sent him home with me, with strict intructions and lots more out patient blood tests, he rested up for a couple of weeks, doing very little, this week his energy levels are back to normal and driving me nuts.