STEMI Without The "STE"

HPI: 57 y/o woman with remote hx of CABG/PCI presents with 2 hrs of 6-10/10 substernal chest tightness and SOB. No recent cardiac events/complaints. Initial troponin is 1.48.

EKG Interpretation: normal sinus rhythm at a rate of 71 with a normal axis. Narrow QRS complexes throughout, normal intervals. Mild ST elevation in I, aVL, and V2.  Inverted T wave in III with mild ST depression as well. No previous EKG available for comparison.

Discussion: Although this patient does not have an obvious STEMI on their EKG, there is mild elevation in I, aVL and V2 with reciprocal changes in III, a pattern similar to the South African flag.  Concern should be high for a high lateral MI which is an area of that is poorly represented by standard EKG lead placement.  In this case, the patient had an acute thrombotic occlusion of a diagonal branch of the LAD artery.

On the initial EKG, the patient has lower voltages in their limb leads as well as V3-V6.  Although they don’t have frank ST elevation ≥ 1 mm in any lead other than V2, their mild ST elevation should be concerning given the low(er) QRS voltage. Move one of the V leads higher into the left axilla (2-3 interspaces) to obtain a tracing of the high lateral wall. Make sure to discuss with Cardiology your concern for a potential STEMI despite the lack of qualifying ST elevation. 

Management:
- Obtain EKG tracing of high lateral wall
- Labs including troponins as well as CXR
- MONA, heparin
- Cardiology consult emphasizing the concern for ST changes in the setting of low QRS voltage
- Consider emergent cath for patients with persistent chest pain and persistent ST changes

By: Dr. Andrew Godfrey