What is pathophysiology of atrial fibrillation?

Incredibly complex: This still remains unknown to a large extent. We know the pathophysiology is not the same in everyone. Many people have afib as a result of frequent bursts of abnormal electrical activity in the pulmonary veins, which enter the heart and trigger atrial muscle fibrillation. However, stretching of atrial muscle can be a stimulus to trigger fibrillation, as can ischemia (limited blood flow) in some.

If you know...: The picture goes something like this: an unknown insult causes mild deposition of scar tissue and changes in the electrical properties of some atrial muscle. The atrium then dilates and more scar deposits. Thereafter, it becomes possible for a focus called a rotor to establish itself, waiting to be triggered by extra beats, usu from pulmonary vein foci. Rarely, the pvs can cause fib alone.