Fainting and heart problems: what to know

The heart normally keeps blood moving to the brain. A rhythm that is too fast, too slow, or irregular can briefly reduce that flow. Structural heart problems can also limit output, particularly during exertion. Fainting with palpitations, chest discomfort, breathlessness, or no warning is more concerning than a spell preceded by heat, nausea, and prolonged standing. Anaemia, dehydration, and hypoglycaemia can also cause collapse or similar symptoms, so the story should be assessed rather than guessed from one symptom.

After an episode, lie down until steady and avoid driving or operating machinery. Ask someone to stay with you if you remain dizzy. Write down your posture, activity, symptoms, known heart history, medicines, and the time needed to recover. A clinician may check blood pressure, an electrocardiogram, blood tests, or a longer rhythm recording depending on the account.

Call emergency services for fainting with chest pain, severe breathlessness, sustained palpitations, collapse during exercise, injury, abnormal breathing, prolonged confusion, or new neurological symptoms. Seek prompt review for a first episode, repeated blackouts, a family history of sudden cardiac death, or fainting while seated or lying down. Do not stop prescribed heart medicine without medical advice.

Ask whether the episode could be rhythm-related, which tests are appropriate, and whether activity or driving should be restricted while you are being assessed. Confirm how to respond if palpitations or light-headedness return.