ST Elevation in a Pre-Op Patient

It was 10 am on a weekday and this Mid-70’s male was sent to my ED from the clinic where he was having a routine pre-op assessment for an upcoming minor day surgery. This patient was sent by the ECG technician because of the following ECG.

The triage nurse showed me the ECG. Yup, those are scary ST elevations in V3-V5, not to mention Q waves.

If this ECG looks familiar, you may have seen it on Amal Mattu's excellent ECG website, as it was featured a few weeks ago (ekgumem.tumblr.com/)

A little more info...

No previous ECG’s. No symptoms (no CP, no SOB, no N/V, no diaphoresis).

PHx – HTN, lipids, smoker, “kidney cysts”

Meds – adalat, atenolol, lisinopril, lipitor

Vitals: T-36.7, p50, BP 139/76, RR 18, Sat 98%

Where would you want the patient?

Without a more detailed history, I was inclined to place him in our acute area and asked for a CXR and cardiac workup, including another ECG when the patient was moved to a room.

The repeat ECG was essentially unchanged.

All labs were normal, including CK and troponin.

CXR was normal.

I considered the DDx of ST elevation (for a great review of the DDx of ST elevation, check out this study by Edhouse et al in BMJ 2002 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1122906/):

• STEMI
• Pericarditis/Myo-pericarditis
• Benign Early Repolarization
• LBBB
• Brugada syndrome
• Aortic dissection
  Hyperkalemia
• Subarachnoid hemorrhage/ICH
• Coronary aneurysm
• LV aneurysm

From H&P we can eliminate pericarditis, dissection and intracranial bleed. His ECG doesn’t fit with Brugada, LBBB or BER. His electrolytes were normal.

This was not a STEMI. I suspected an LV aneurysm (LVA). How can one differentiate between STEMI and LVA?

• Clinical context: STEMI requires chest pain or chest pain equivalent (SOB, N/V, diaphoresis)
• ST changes not dynamic in LVA
• Usually no reciprocal ST depression in LVA
• Always compare to old ECG (could not do in this case)

Luckily it was the morning of a weekday and a STAT echo in the ED could be arranged.

Echo results:

• Grade 3 ventricle
• Evidence of large apical infarct
• Apical aneurysm with 2.5 cm thrombus

A bit of extra info on LVA:

• Causes persistent ST elevation > 2 weeks post MI
• Most often Anterior MI (may also be Inferior MI)
• ST elevation due to scar formation and paradoxical wall movement
• Causes: post MI, cardiomyopathy, cardiac infection, congenital

Clinically significant because:

• May cause cardiomyopathy/CHF
• Arrythmogenic --> may cause sudden cardiac death
• Potential for thrombus formation --> Risk of embolization --> stroke!

ECG findings of an LV aneurysm:

1. ST Elevation > 2 weeks post MI
2. Primarily precordial leads
3. May be concave or convex
4. Often well-formed Q-waves or QS waves
5. T-waves tend to be small compared to QRS

So let’s revisit the patient’s ECG with this info in mind:

Pt’s Course in the ED:

• A few runs of non-sustained VT while in ED awaiting CCU bed
• Started on heparin drip and transitioned to coumadin
• Surgery cancelled
• Set up for myocardial perfusion imaging, which confirmed previous MI(s)

Learning points from this case:

• All that is ST elevation is not MI/pericarditis
• If cannot explain ST elevation clinically, consider STAT echo in ED to r/o alternative causes
• LV aneurysm causes persistent ST elevation due to wall motion defect
• High risk for arrhythmia, thrombus formation --> Clinically important!

References and other sources cited in this text:

• lEdhouse, Brady and Francis. ABC of clinical electrocardiography: Acute myocardial infarction – Part II. BMJ. 2002 April 20; 324(7343): 963–966. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1122906/
• lDr Smith’s ECG Blog (http://hqmeded-ecg.blogspot.com/search/label/LV%20aneurysm)
• lLife in the Fast Lane (lifeinthefastlane.com)
• Amal Mattu's EKG of the week (ekgumem.tumblr.com/)