Sometimes, atrial fibrillation can lead to the following complications:

Heart failure. Atrial fibrillation alone, especially if not controlled, may weaken the heart, leading to heart failure – a condition in which your heart can’t circulate enough blood to meet your body’s needs.

Stroke. In atrial fibrillation, the chaotic rhythm may cause blood to pool in your atria and form clots. If a blood clot forms, it could dislodge from your heart and travel to your brain. There it might block arterial blood flow, causing a stroke. The risk of stroke in atrial fibrillation depends on your age (you have a higher risk as you age) and on whether you have high blood pressure or a history of heart failure or previous stroke, and other factors. Most people with atrial fibrillation have a much greater risk of stroke than do those who don’t have atrial fibrillation. Medications such as blood thinners can greatly lower your risk of stroke or damage to other organs caused by blood clots.