Yes it is possible but not probable. It could be caused from old scar tissue from your earlier MI or from errant foci in the Pulmonary Veins. It is a good sign that your A-Fib converted on its own in such a short time. That means that with medication your A-Fib should be able to be controlled. I am in the same boat as you. My A-Fib lasted only four hours and converted on its own and has been normal for almost two years now just by taking Cardizem and Toprol. Mine may have been caused by Drinking a few glasses of wine. Caffeine can also cause A-Fib. There are many triggers of A-Fib. Research them.
Nunik,
Thanks for the (international?) post.
The answer to your question is:
Yes.
The American College of Cardiology has a naming system for atrial fibrillation (afib) that is based on how often a patient gets the atrial fibrillation and by how hard it is to make it go away. See www.ACC.org for details.
Paroxysmal afib comes and goes. Once someone has their first episode, they are much more likely to have a second episode than the average person, with at least a 40-50% recurrence in the first year. Persons with a first-time episode should be screened for reversible causes of atrial fibrillation, such as hyperthyroidism.
Persistent afib is afib that requires cardioversion, chemical or electric, to make it go away.
Chronic afib is afib that is almost always present. Chronic afib can start out as paroxysmal afib that was never treated, or as persistent afib that was treated and then recurred.
Hope that helps.