You should get a formal and comprehensible (for you) assessment of your risk if you take the oil and if you decide to forego it from henceforth. If your ablation was successful, then you probably don't have much to worry about, especially if you only take a small dose of the oil. If you're taking more than the daily recommended, or more than what your own physician says you should take (he she knows you best and has other information about you that will help with the decision), then you must be able to compare the relative personal risk of recurring AF over what you hope to prevent, also as a probability, if you stop taking the oil.

You can get decent protection by using other oils, not just fish oil, or walnuts, or avocado...several other options.