The cardiologist I just started seeing prescribed 10 mg of Atenolol as a means to decrease my heart rate, but mostly because he believes just about anyone who has had evidence of plaque build up should be on a beta blocker. I had a stint put in 5.5 years ago, but did not have a heart attack. My artery was narrowed to about 90-95%, so I was pretty close, and having some discomfort in my chest/arm. I seemed to be doing well since with overall good cholesterol numbers and no chest pain which includes some high intensity exercise with no problem. I have taken Lisinopril for since I had my stint put in as more of a preventative measure than having excessive blood pressure. After taking Atenolol, it makes me feel like something is wrong with me, but I can t describe what issue well. I m more aware of my heart rate, and it is slower, but something feels wrong with the rhythm maybe. Could my blood pressure be too low since I m taking 2 meds that lower BP? I ve read they can both increase potassium. I think my heart rhythm is sensitive to NOT having enough potassium, so I m not sure how that could be the problem, yet maybe too much potassium is affecting my rhythm?