ECG Pointers: LVH vs STEMI

Author: Lloyd Tannenbaum, MD (Emergency Medicine Resident, San Antonio, TX) // Edited by:  Jamie Santistevan, MD (@jamie_rae_EMdoc – EM Physician, Presbyterian Hospital, Albuquerque, NM); Manpreet Singh, MD (@MPrizzleER – Assistant Professor of Emergency Medicine / Department of Emergency Medicine – Harbor-UCLA Medical Center); and Brit Long, MD (@long_brit  – EM Attending Physician, San Antonio, TX)

Welcome to this edition of ECG Pointers, an emDOCs series designed to give you high yield tips about ECGs to keep your interpretation skills sharp. For a deeper dive on ECGs, we will include links to other great ECG FOAMed!

The Case:

Only 15 minutes left of your busy overnight shift. You’re wrapping up your last chart when your attending looks at you and says, “The patient they just pulled back doesn’t look so good. You better go take a look…” You walk in the room and see an older African American male clutching his chest. He is diaphoretic and looks very uncomfortable. Your nurse hands you this EKG:

There is sinus rhythm and a normal axis. There are ST segment depressions (inferior and lateral leads) and ST segment elevations (anterior leads). There are deep S waves in the precordial leads. Does this meet STEMI criteria, or is it just Left Ventricular Hypertrophy (LVH)?

What is LVH?

When the left ventricle is constantly pumping against increased resistance (chronically high blood pressure, aortic stenosis), the muscle hypertrophies like any other muscle. The thickened muscle wall takes longer to depolarize and longer to repolarize. All of this results in increased R-wave amplitude in the left sided leads (I, aVL, V4-V6) and increased S-wave depth in the right sided leads  (III, aVR, V1-V3). Repolarization abnormalities can cause ST segment depressions and T-wave inversions in the lateral leads, known as the left ventricular strain pattern.

Let’s also refresh ourselves with the STEMI criteria [1]:

  • New ST Elevation at the J point in two contiguous leads of >1 mm in all leads other than V2-V3
  • For Leads V2-V3, the following cutoffs apply:
    1. >2 mm of ST elevation in men >40
    2. >2.5 mm of ST elevation in men <40
    3. >1.5 mm of ST elevation in women of any age

So, looking back at our EKG, it seems like he may meet STEMI criteria. But the voltage on this EKG is awfully high. There are several different voltage criteria for diagnosis LVH. Some of the more popular ones are listed below. Remember, voltage criteria alone are not diagnostic of LVH.

Voltage criteria for LVH [2]:

Limb Leads:

  • R wave in lead I + S wave in lead III > 25 mm
  • R wave in aVL > 11 mm
  • R wave in aVF > 20 mm
  • S wave in aVR > 14 mm

Precordial Leads:

  • R wave in V4, V5 or V6  > 26 mm
  • R wave in V5 or V6 plus S wave in V1 > 35 mm
  • Largest R wave plus largest S wave in precordial leads > 45 mm

The bolded criteria are known as the Sokolow-Lyon criteria [3]. It is one of the most frequently used equations when looking for LVH.   Another formula to diagnose LVH is known at the Cornell-criterion. It is more accurate for diagnosing LVH than the Sokolow-Lyon criteria, but harder to remember, so less often used [4]. The Cornell-Criterion are posted below:

  • R in aVL and S in V3 >28 mm in men
  • R in aVL and S in V3 >20 mm in women

Well, now what?

It appears that our patient meets LVH voltage criteria. With LVH, it is common to see a strain pattern, where there are ST Depression and T Wave inversions in the left sided leads [2]. Is this patient having LVH with strain or is it a true STEMI?

Armstrong et al introduced a flow chart to help identify a STEMI in patients with LVH[5]:

Below is a marked EKG in V2 to see if we’d meet STEMI criteria by their flowsheet:

Case Conclusion:

By their criteria, this patient did not meet STEMI criteria. Because of the way the patient was presenting and the concerning EKG, a CODE STEMI was called on this patient. The staff cardiologist and senior cardiology fellow examined the EKGs and felt that it was likely LVH with strain, but given his presentation, they took him to the cath lab for an emergent cath to confirm. He was found to have clean coronaries.

The major conclusion of most of the algorithms for LVH vs STEMI is that the only way to definitively prove that it is LVH and not a STEMI is to take them to the cath lab. If in doubt, discuss the EKG with your cardiology colleagues. Given how acutely this patient presented, better to be safe and overcall than miss a STEMI.

Interestingly, Dr. Smith, of Dr. Smith’s EKG blog does a write up on LVH with Strain vs STEMI and reviews the above flowchart.

References/Further Reading:

  1. Aboufakher, R. ECG in STEMI: Importance and Challenges.
  2. Burns, Edward. 18Mar2017.
  3. Sokolow M, Lyon TP: The ventricular complex in left ventricular hypertrophy as obtained by unipolar precordial and limb leads. Am Heart J 37: 161, 1949
  4. De Jong, JSSG. 8Oct2014. Chamber Hypertrophy and Enlargement.
  5. Armstrong, EJ, et al. Electrocardiographic Criteria for ST-Elevation Myocardial Infarction in Patients With Left Ventricular Hypertrophy. American Journal of Cardiology. 977-83.

2 thoughts on “ECG Pointers: LVH vs STEMI”

Leave a Reply

Your email address will not be published. Required fields are marked *