Tips When Performing a 12-Lead ECG on a Prone Patient

Nurses have certainly learned a lot about pronation therapy recently, including how to pronate, when and why to pronate, and the clinical challenges of caring for a prone patient. At AACN, our team of clinical practice specialists has been fielding questions and providing clinical answers to our community from many sources.

I’m happy to share information about one of those clinical answers that had eluded us: What does the nurse need to know about doing a 12-lead ECG on a patient who is in a prone position?

The issues include:

• Where should electrodes be placed for a 12-lead ECG on a prone patient?
• What changes on the ECG when the patient is prone?
• What is important to know when interpreting the 12-lead ECG when the leads are placed on the patient’s back?

A recently published article by Nguyen and other physicians at Rush University Medical Center discusses the case of a woman positive for COVID-19 whose treatment included prone positioning. They compared her 12-lead ECG in both supine and prone positions and discussed the differences and implications for practice.

• Lead placement – Place all leads on the patient’s back directly opposite their typical anterior position. This means V1 is placed to the right of the spine at the 4th intercostal space, and the remaining V leads are to the left of the spine in their corresponding “normal” pattern and landmarks (intercostal spaces and mid-scapular line), with V5 at the posterior-axillary line and V6 in the usual mid-axillary line placement. Limb leads need to be placed on the back, with their usual left and right orientation. There’s a photo of anterior and posterior lead placement in Nguyen’s article.
• What changes – The apex of the heart falls forward to the anterior chest wall and caudally (toward the abdomen) when the patient is prone, and becomes more globular in shape. This moves the heart farther away from leads that are on the posterior chest wall with more tissue and bone between the heart and the electrodes. V-leads will have lower amplitude, as will lead aVR.
• How does this change the information from the ECG? P waves are likely to be very small. Q waves will be larger in leads V1 to V3 (don’t misinterpret this as an anteroseptal infarct; consider if the patient’s clinical case suggests acute coronary syndrome). ECG evidence of ischemia or infarction will benefit from expert interpretation.

What else do you need to know?

It is critically important to make sure that everyone looking at the ECG performed on a prone patient knows it was obtained with posterior chest leads. Otherwise misinterpretations are likely, which can result in additional diagnostic and possibly unneeded interventions.

What has been your experience with obtaining a 12-lead ECG on a prone patient?