Hello, as I can understand you have undergone ablation for atrial fibrillation and are presently on bisoprolol( beta blockers). As per current available literature on the drug, weight gain is not a routine side effect of the drug. However, there are a few case reports only in which the causal relationship is not proven. In your case I would advise you to go retrospectively , that is we follow an approach of treating the common cause of obesity rather than attributing it to the drug. 1. Look if you are taking some other meds which have a clear association with weight gain 2. Get your lipid, sugar and thyroid profiles done as they are commonly associated 3. Last but not the least start treating yourself a. cut down your caloric intake ( high prot low carb and low fat diet) b. restrict your salt intake to c. Start aerobic exercise or brisk walking to begin with, atleast 5 times in a week ( 30 min/ day) d. maintain a weight log and calorie intake diary I have given you an outline to follow. you can always get back if you something additional to tell or any queries . Thanks