What should you know about types of electrocardiogram?

A resting ECG records the heart while you lie still, using small sticky electrodes on the chest and limbs. An exercise ECG records electrical activity while you walk or pedal under supervision; it can show how the heart responds to increasing demand. An ambulatory ECG uses a portable recorder worn during ordinary activities for longer monitoring, making it useful when palpitations or rhythm changes come and go. A single ECG can provide helpful information but may not capture an intermittent problem. The tracing can support assessment of rhythm, conduction, heart strain, and signs that need further testing.

Wear clothing that allows access to the chest and lower limbs, and tell the clinician about medicines, implanted devices, skin sensitivity, and recent symptoms. Avoid applying oily moisturiser where electrodes will be placed. During monitoring, record the time of palpitations, chest discomfort, dizziness, or breathlessness and what you were doing. An ECG does not by itself explain every symptom; a GP consultation may combine it with an examination, blood tests, imaging, or referral.

Call emergency services for new or severe chest pressure, breathlessness at rest, fainting, collapse, or sudden weakness with a racing or irregular heartbeat. Do not wait for a routine ECG if symptoms are severe or ongoing. Arrange medical review for repeated palpitations, unexplained dizziness, reduced exercise tolerance, or swelling. An ECG may be used while assessing conditions such as angina, atrial fibrillation, or heart failure, but the tracing needs clinical interpretation.

Which ECG format fits my symptoms? How should I prepare? Should I keep an activity and symptom diary? What did the tracing show, and do I need another test? When should I seek urgent help?