Posterior Myocardial Infarction - Are We Really This Bad?

From the excellent ECG repository at LITFL

Now, apparently a significant number of us are potentially missing and failing to diagnose posterior myocardial infarctions. Well, we are, according to this British study, published in this month's EMJ. Docs from ED and acute medicine at two teaching hospitals, and paramedics from the regional ambulance service were asked to interpret ECGs with changes associated with PMI in the context of patients with chest pain. This was compared with their ability to diagnose anterolateral STEMIs. Both doctors and nurses were also tested on their knowledge of lead positioning for a posterior ECG.

Diagnosing PMI successfully - Doctors - 38% (44/117), Paramedics - 10% (5/50). This was significantly worse than their ability to diagnose STEMIs 

Correct lead placement for posterior ECG - Doctors - 20%, Nurses - 22% (13/60)

The autors concluded that routine use of posterior leads in the standard assessment of chest pain patients may identify an additional 7% of STEMIs. I would also suggest implementing improved access to education for ECG interpretation for the relevant emergency personnel.

Lead V2 Appearance 

ECG Pearl

Posterior MI suggested by

- ST depression in V2-3

- Tall, broad R waves (>30ms) in V2-3

- Dominant R wave (R/S Ratio >1) in V2

- Upright terminal portions of the T waves in V2-3

Lead Placement for Posterior ECG

From Academic Life in EM

Emerg Med J. 2012 Jan;29(1):15-8. Epub 2010 Oct 20.

Excellent Summary of Posterior Myocardial Infarction on LITFL

Posterior Myocardial Infarction: The Dark Side of the Moon - an excellent case summary and review.