What should you know about cardiogenic syncope causes?

Fainting happens when the brain temporarily receives too little blood flow, leading to a short loss of consciousness and loss of posture. A heart-related cause can involve an unusually slow, fast or irregular rhythm, or a problem that limits how well the heart pumps or blood leaves the heart. Fainting during exertion or without warning deserves particular attention.

Not every faint is cardiogenic. Dehydration, anaemia, low blood sugar and reflex fainting can also cause collapse. Atrial fibrillation may produce an irregular heartbeat, but fainting has several possible causes and cannot be attributed to one condition from the symptom alone.

Arrange prompt medical assessment after an unexplained faint, especially if it occurred while exercising, followed palpitations, caused an injury, or happened with known heart disease. Write down what happened before the event, whether there was warning, how long recovery took, and any medicines or illness around that time. A clinician may check blood pressure, heart rhythm and blood tests, with further heart testing if needed.

Until assessed, avoid driving, heights, swimming alone and other situations where another collapse could cause serious harm. Sit or lie down as soon as warning symptoms appear.

Call emergency services if fainting occurs with chest pain, severe breathlessness, a sustained abnormal heartbeat, seizure-like movements, significant injury, confusion that does not clear, or weakness on one side. Urgent assessment is also needed when someone collapses during exercise or while lying down. Do not give food or drink to a person who is unconscious.

Ask whether the episode could be heart-related, whether you need an ECG or longer rhythm monitoring, and whether medicines or an electrolyte problem may contribute. Ask when it is safe to drive, which activities to pause, and what symptoms should trigger emergency help.