Diet & exercise is great but will not be enough for many heart conditions that require beta blockers.
For example, there can be electrical irregularities but no real physical cause such as from PVCs, PAC's the most common forms of arrhythmias, etc. where beta blockers like Metoprolol should be taken forever to lessen the potential strain of on the heart. In the majority of cases, PACs occur in normal healthy individuals - especially older - without any evidence of heart disease.
The surgical possible "fix" of killing the tissue sending out the premature electric pulse is usually not recommended unless the symptoms (palpitations etc) interfere with everyday life.
In some cases, exercise can increase the arrhythmias which is why patients often have stress tests to see if they increase or not during exercise. Of course, good diet and exercise is beneficial but not the full answer and won't help much for common heart arrhythmia issues.
Yes, I have had these PVC/PAC's for years but very rarely feel them. Had all the extensive heart tests and nothing is wrong physically just an electrical problem that many have.
To the main issue of drugs and "performance", I have been lucky. In my 70s with some help from Viagra have not had any issues other than the normal lack of "force" and lower output

I have been on Metoprolol for years. Other medications may interfere more and different men react differently based on individual situations.