Question: What causes atrial fibrillation?
Answer :No one knows precisely why one patient suddenly starts developing atrial fibrillation. But we do know the situation in which atrial fibrillation occurs -- and those conditions or situations, the most important of which is age. Atrial fibrillation is very rare before the age of 50. But beginning at the age of 50 it becomes more common, and by the time someone's 80 years old, one in 10 patients or people have atrial fibrillation. So it's clearly age related.
And it's also related to other cardiac conditions. So someone who's had cardiac heart failure, has hypertenstion, who's obese, is more likely to develop atrial fibrillation than someone who doesn't have those conditions. So why someone gets it, no one precisely knows. But we do know the settings in which it's more likely to occur.