What Causes Difficult In Breathing In People With Hypertrophic Cardiomyopathy?

I m 37 years old. 3 years ago I had my mital and aortic valve replaced with mechanical valves. 16 years ago I recieved a ICD. I take metoporol and coumadin. I just had an echo that was normal. I have low blood pressure and a slow heart beat, 60 s. My cardiologist says that is normal for me. I ve been having hard heart beats that keep me up at night and sometime annoy me at work. I work out when I can 3-4 times a week. I mostly do cardio and a small amount of lifting. I have Hypertrophic cardiomyopathy so my workouts aren t what I wish they were. Recently when playing softball I m easily winded. More than usual. I told my cardiologist and he wasn t too concerned. He said he didn t want to go looking for a problem. Any advice?