I don't know for sure, but heart problems & penis & erectile function can sometimes be linked. For example, in older guys, a complaint of poor erectile function can be the first sign of arterial blockages to the heart. It is somewhat normal for OLDER guys to lose a little size (both length & girth) as they age, but at 22, that seems unlikely. However, because you do have heart issues, I would ask the Dr. if there's any possible linkage. Masturbation (even so-called 'excessive' masturbation) would not cause issues with your heart...