I had atrial fib for almost 10 years. Tried about every substance known.....and nothing worked. Went to UNC heart center and told them to fix it or stop it. They did an ablation and I have a new life now. Blood thinner is only helps prevent a stroke but does nothing to resolve or mitigate a-fib. And long term use of Coumadin is associated with hardening of the arteries (from what I have read). Get an ablation and fix the issue.