What does fainting feel like with atrial fibrillation?

Atrial fibrillation makes the heartbeat irregular. In some episodes, the heart may not move blood efficiently for a short time, causing reduced blood flow to the brain and a faint. Some people feel fluttering, chest awareness, breathlessness, tiredness, or dizziness instead of fully passing out. Fainting has several possible causes, so the symptom alone cannot identify atrial fibrillation.

Lie flat and raise your legs if you can do so safely. Loosen tight clothing, stay still, and ask someone to remain with you. Do not drive, climb, or stand quickly after recovering. Arrange medical assessment, especially if this is a first episode or your heartbeat remains irregular.

Call emergency services for fainting with chest pain, severe breathlessness, a sustained fast heartbeat, injury, confusion, weakness on one side, trouble speaking, or failure to wake normally. Urgent assessment is also needed if fainting happens during exertion or while you are known to have heart disease.

Ask whether an electrocardiogram or heart-rhythm monitor is appropriate, whether medicines could contribute, and which symptoms should prompt emergency help. Note what you felt before the episode, how long recovery took, and whether anyone saw unusual movements.