How long does an ECG take to work for a heart attack?

The test itself is quick: small sticky sensors are placed on the chest and limbs while you lie still. The recording usually takes only a few minutes. A clinician can review the tracing promptly, especially when chest pain or other warning symptoms are present.

An ECG may show changes in the heart's rhythm or electrical pattern that support a heart attack diagnosis. A normal first tracing does not always settle the question, particularly if symptoms are continuing or started recently. The clinical team may repeat the ECG and compare it with earlier recordings.

Blood tests that look for heart muscle injury are often used with the ECG. Your symptoms, examination, medical history and test results are considered together rather than relying on the tracing alone.

If you have possible heart attack symptoms, stop exertion, sit or rest, and seek emergency medical help. Describe when the symptoms began, whether they are changing, and any medicines or heart conditions you have. Do not drive yourself if you feel faint, breathless or seriously unwell.

At the healthcare facility, keep still during the recording so the tracing is clearer. Tell staff if chest discomfort, sweating, nausea, shortness of breath or pain spreading to the arm, back, neck or jaw develops or worsens.

Call emergency services immediately for pressure, squeezing or pain in the chest that is severe, persistent or returning, especially with shortness of breath, cold sweating, faintness or nausea. Urgent assessment is needed even when symptoms are not dramatic, because heart attack symptoms can vary.

Do not wait for an ECG appointment if symptoms suggest a heart attack. Emergency teams can begin assessment during transport and continue testing when you arrive.

You could ask: What did my ECG show? Do I need another ECG or a blood test? Which symptoms should I report immediately? When can I safely return to normal activity?