question: Hello doctor, My sister had her aortic valve (tissue) replaced last week. The operations were uneventful, though she has been suffering from nausea and weakness. Each time she is given Beta-blockers to prevent atrial fibrillation. Before the operation, her heart rate was 100 beats per minute, which attributed to the stenosis. After the surgery, her heart rate has remained around 100 without Beta-blockers. The hospital staff has now reduced the Beta-blocker dosage from 10 to 2.5 mg, yet she still feels very weak. With Beta- blockers, her heart rate has descended to 86, but she feels terrible. My question is, If she feels fine without the Beta-blockers, could it be safe for her to discontinue using Beta-blockers to avoid the weakness or nausea? Or would this be a bad decision?