When Do We Need Additional Chest Leads?

Following a standard (12 lead) ECG, if posterior (V7, V8, V9) or right sided (V4R) infarction is suspected, additional chest leads are required in:

• Patients with inferior ST segment elevation because the majority of right-sided infarcts and posterior infarcts occur as extensions of inferior infarcts. This may affect management patients with right sided MI and hypotension may respond to fluid resuscitation.
• Patients with anteroseptal ST segment depression (indicating ischaemia) because this may be masking true posterior infarction; this will, if demonstrated, affect immediate treatment.

Standard and posterior ECG lead placement

Figure 1: Standard and posterior ECG lead placement

Click on the links below to see standard-lead and posterior-lead ECG traces.

Standard chest lead

Additional posterior leads

Learning Bite

Be alert to the need for right sided or posterior leads when diagnosing STEMI they should be performed as routine in all patients with inferior ST elevation or anteroseptal ST depression.