The DR diagnosed me about 4 years ago with A-fib. The Dr. put me on 25 mg of Atenolol. I immediately noticed side effects of dizziness. I told the Dr. and he suggested I cut the dosage in half. That did the trick for that side effect. However, over time I have concerns about other side effects that I don't know if they just come with getting older or that they are tied to the Atenolol. Iby hobnober - AFIBBERS FORUM