Consequences of atrial fibrillation

If atrial fibrillation is left untreated, it can result in serious consequences, such as stroke and congestive heart failure.

Stroke

Because the atria are not beating effectively, blood isn't pumped efficiently through the heart. It can pool in the atria and form clots. If a clot breaks loose from the heart, it can enter the bloodstream and travel to the brain, where it may block blood flow and cause a stroke.

Heart failure

Atrial fibrillation causes the ventricles to beat rapidly. If this continues for a period of time, the ventricles can become weakened, leading to heart failure.

Atrial fibrillation fact sheet (pdf)