Sorry to hear about your atrial fibrillation. When seeing patients who experience symptoms in the evening such as yours, we sometimes prescribe a twice a day dose of Toprol XL. However, you should discuss this with your doctor.
Vitamins E and C are ineffective blood thinners. Though your episodes don't seem to last over 48 hours it is possible for you to be experiencing asymptomatic episodes which last longer.
Atrial fibrillation is associated with a yearly ~5% risk of stroke in high risk individuals. People who are over the age of 60, have diabetes, hypertension, prior stroke,congestive heart failure or structural heart disease should be treated with coumadin. I would recommend discussing your concerns with your cardiologist. You may also consider seeing an electrophysiologist (EP), which is a cardiologist specializing in rhythm disturbances. Hope you feel better.
Thanks for your question,