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Orthopedics

 A 60 year old woman presents to the emergency department complaining of chest pain for the last 3 hours. She has a history of rheumatoid arthritis and takes indomethacin.  She has no prior history of similar pain. What does the EKG show and what is the diagnosis?

Rate:    90

Rhythm:  sinus rhythm

Axis:    left axis deviation

PR:    normal

QRS: Narrow complex, small R wave in V1, tall R waves in V2-V4, Q waves in II, III, and AVF

ST:    depression V2-V4

EKG Diagnosis: Posterior myocardial infarction

Clinical Diagnosis:  Acute posterior myocardial infarction

Does this patient require immediate OMT consultation in the acute setting? No

Practice Points: - True posterior myocardial infarction is unusual and is not easily recognized as no leads in the conventional 12 lead EKG are posteriorly situated

• -Lead V1 reflects posterior pathology but the appearances are the inverse of normal; ST depression and R waves in V1 are equivalent to ST elevation and Q waves elsewhere
• - A useful trick is to flip the EKG over and look through the paper at a bright light. The classical EKG changes of infarction will then be apparent
• - In this EKG tracing the R wave in V2 is bigger than that in V5 which is characteristic of a posterior infarct

The cardinal features of a true posterior infarct are:

• Large R waves in V1-V3 ( reciprocal of Q waves in a posterior lead if one existed)
• ST depression in V1-V3 if the infarct is recent
• Tall T waves in V1-V3 ( analogous to T wave inversion)
• Posterior changes may be further confirmed by recording chest leads V7-V9. These extend onto the posterior chest and record the posterior surface of the heart.  Acute changes in these leads will be the typical ST elevation and Q waves of a myocardial infarction

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