From the bottom up

While you begin your consult to the local PCI/CABG/heart center of excellence, you notice the following tracing spit out from the monitor. The patient is remains hemodynamically stable but states that he's "a bit weak." He's also diaphoretic. Vitals:

BP: 110/60

P: 70
R: 18
Sp02: 96%

Interpretation
Sinus rhythm, first degree AVB, inferior lateral wall MI with posterior wall extension.

Discussion
There's ST elevation of > 1mm in leads II, III, and aVF.  These leads examine the "bottom," or inferior portion of the myocardium. There's also STE present in V6. Clear-cut reciprocal change is present in leads I and aVL. There's badness also going on in V1-V3. The ST depressions, tall R waves, and upright T waves are concerning for posterior wall myocardial infarction. Posterior wall MI rarely occurs in isolation and most commonly accompanies inferior wall ischemia. Leads V1-V3 indirectly reflect what's going on in the back of the heart. Placement of posterior leads on this particular patient would likely reveal ST segment ELEVATION. Also notice the long PR interval in V5 and V6. The right coronary artery (RCA) supplies the sinoatrial node. Myocardial ischemia that occurs in the territory supplied by the RCA can produce heart blocks and conduction disturbances such as the first degree block displayed in this tracing.

Posterior wall MI
-ST segment depression in leads V1-V3
-Tall R waves in V2-V3
-Usually upright T waves

EMS Pearls-
Avoid morphine in patients with massive or large territorial MI's; morphine increases the potential for respiratory depression and pulmonary edema