What should you know about cardiovascular syncope?

Syncope is a short loss of consciousness followed by spontaneous recovery. A heart rhythm that is too slow, too fast, or irregular can reduce the brain's blood supply. A valve problem or another circulation issue may also be involved. Fainting can instead be related to dehydration, anaemia, low blood sugar, standing for a long time, heat, pain, or a reflex response. The circumstances matter: fainting during exertion, while lying down, or with palpitations deserves particular attention. A witness account can help describe colour change, movements, duration, and recovery.

If someone faints, lay them flat and raise their legs when injury is not suspected. Check breathing, loosen tight clothing, and keep the area safe. Do not give food or drink until they are fully alert. After recovery, arrange medical assessment, especially after a first episode, an injury, or a history of heart disease. A clinician may review medicines, blood pressure, an electrocardiogram, and blood tests; further monitoring depends on the story and examination.

Call emergency services if the person does not wake promptly, is not breathing normally, has chest pain, severe breathlessness, a sustained fast or irregular heartbeat, a serious injury, or new weakness or speech difficulty. Seek urgent assessment for fainting during exercise, fainting without warning, repeated episodes, or a close family history of sudden cardiac death. Do not drive until a clinician has advised you.

Ask what may have triggered the episode, whether your medicines or hydration need review, and whether heart-rhythm monitoring is appropriate. Tell the clinician about palpitations, exertion, posture, warning symptoms, injuries, and any witness observations.