No one should go off any drug including metoprolol other with their doctor s guidance. Metoprolol controls your heart rate so it doesn' t go too high which is typical when go into AFib. so you need this drug to control the rate. Heart rhythm is a different story: that s where you use a drug (antiarrhythmic drug such as dofetilide)or procedure ( such as ablation) to control the rhythm to keep it regular instead of going into atrial fibrillation. Rate and rhythm are two components of your heart treated with different meds and/or procedures
respectively.