Are there any steps i can take to prevent mild atrial fibrillation from getting worse?

Yes: Downstream treatments are considered to have small benefits based on clinical studies once af is diagnosed (in other words damage is already done). I do believe that therapeutic lifestyle changes are important for some. These would include minimizng alcohol, controlling weight, getting adequate exercise, controlling blood pressure, and assessing and treating sleep apnea.

Stay or get healthy: There are many things that may worsen atrial fibrillation. These include excessive alcohol use, caffeine and being overweight. If any of these apply to you, try to improve them. You should also work with your doctor to ensure you don't have an underlying heart valve problem, coronary artery disease or a thyroid disorder that is causing atrial fibrillation.