EKG
Last week’s 5-minute EKG discussion was lead by our APD, Dr. Scott Heinrich.
You get handed this EKG from a patient in triage with chest pain. Should you activate the cath lab?
…
The answer: No
This EKG is showing left ventricular hypertrophy (LVH) with repolarization abnormality, also known as LVH with strain. This can be easily confused for ischemia, so how do we differentiate between the two?
First and foremost, you must meet criteria for left ventricular hypertrophy. While the gold standard for diagnosing LVH is through echo, there are several different EKG criteria we can use to diagnose LVH, including:
- S wave depth in V1 + tallest R wave height in V5 or V6 > 35 mm (Sokolov Lyon Criteria)
- R wave in aVL and S wave in V3 > 20mm (female) or >28mm (male) (Cornell Criteria)
- R in aVL > 11mm
- And several other criteria, although these are the most common
In LVH, the myocardium becomes thickened, which causes the electricity to move more slowly through the heart. This slowed conduction causes widening of the QRS and repolarization abnormalities. This will appear on EKG as increased R wave peak time of >50ms in leads V5 or V6 and ST depressions with T wave inversions in lateral (left-sided) leads. It is important to note that in LVH with strain, T wave inversions are often asymmetric, in contrast to the symmetric t wave inversions often seen in ischemia.
Ex: Deep, symmetric inverted t waves in Wellen’s (type B)
In summary, in LVH with strain you will see:
- Lateral leads (I, aVL, V5 – V6) with increased R wave amplitude, time to peak R wave at least 50ms, and ST depressions with asymmetric inverted t waves
- Inferior and anterior/septal leads with deep S waves and ST elevations in V1-V3 (discordant to deep S)
Lastly, here are some tips from EKG guru Amal Mattu that may help to differentiate between LVH with strain and ischemia:
- If voltage criteria for LVH is not met, assume ischemia
- Asymmetric T wave inversions favor LVH with strain (although this is NOT always the case, you can have asymmetric TWI in ischemia)
- Horizontal ST elevations and depressions should be concerning for ischemia
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