What should you know about ECG with spirometry?

An ECG uses small sticky electrodes on the chest and limbs to record the heart's electrical signals. Spirometry uses a mouthpiece connected to a spirometer; you breathe into it in a series of coached manoeuvres. The tests answer different questions, so one does not replace the other.

The ECG can help clinicians assess the heart rate and rhythm and look for electrical patterns that may need further assessment. Spirometry records measurements such as the amount of air you can breathe out and how quickly you can do so. These results can support assessment of breathlessness, wheeze, persistent cough or reduced exercise tolerance.

Together, the tests can help separate symptoms arising mainly from the heart, the lungs, or more than one system. Spirometry may be used when asthma or COPD is being considered, while other lung conditions such as bronchiectasis can also affect the wider assessment. A result is interpreted alongside your symptoms, examination and medical history.

Wear clothing that allows access to your chest and tell the clinician about medicines, especially inhalers, heart medicines and anything that affects breathing. Do not stop prescribed treatment unless the testing team gives you specific instructions. Avoid a heavy meal, vigorous exertion and smoking shortly before testing if your clinic advises this.

During spirometry, you may be asked to inhale fully, seal your lips around the mouthpiece and blow out hard and for as long as instructed. Coughing or feeling briefly light-headed can happen; tell the clinician if you feel unwell. The ECG is generally quiet and brief, with you lying still while the tracing is recorded.

Ask whether you should bring your inhalers and whether the test is checking your breathing before and after a bronchodilator. You can read more about [Spirometry](/treatments/diagnostics-and-screening/spirometry/) and the [Spirometer](/technology/spirometer/).

Seek urgent medical help for severe or rapidly worsening breathlessness, blue or grey lips, fainting, new severe chest pain, confusion, or an inability to speak in full sentences. Do not wait for a routine test if these symptoms are present.

Contact a clinician promptly for breathlessness that is worsening, coughing blood, a new irregular or very fast heartbeat, or symptoms that repeatedly wake you. If you have asthma, COPD or another diagnosed lung condition, follow your personalised action plan while arranging advice.

Ask what each test is intended to investigate, whether any usual medicine needs timing changes, and when you should expect an explanation of the results. You can also ask what follow-up is planned if the ECG or spirometry is outside the expected range, and whether [Inhaler Therapy](/treatments/medical-management/inhaler-therapy/) or a [Smoking Cessation Programme](/treatments/lifestyle-and-wellness/smoking-cessation-programme/) is relevant to your care.