Sunday, July 29, 2018

Chest pain and T-wave inversion in lead V2

This is the ECG of a young man who complained of chest pain.

Here is the computer interpretation:
ATRIAL FLUTTER/TACHYCARDIA (this is obviously incorrect)

I saw the ECG before seeing the patient, indeed before he was even in his room.  
I immediately saw that the computer was incorrect, but I found 2 abnormalities.  
What are they? 

I showed this to several physicians.  
They were worried about the T-wave inversion in V2.

One mentioned "Wellens' waves"

Another asked: "Are these juvenile T-waves?" (very good question!)
For more on this: Persistent Juvenile T-wave Pattern

What do you think?

I keep getting response tweets that T-wave inversion in V2 is normal.  It is not normal.  It is not necessarily pathologic, but it is not normal.  It occurs normally in approximately 1% of males over age 14 but younger than 30.  It is common in young women (these are the typical juvenile T-waves, link to relevant post above).

T-wave inversion in V2 occurs in many pathologies, including posterior MI, pulmonary embolism, Wellens' syndrome.  It is one of the minor criteria for arrhythmogenic right ventricular dysplasia ("Minor: Inverted T-waves in right precordial leads V1-V2")

Here is my list of Normal and Pathologic T-wave inversion:

• Normal t wave vector is leftward, inferior and anterior.
• T waves should be positive in lead II.
• Inversion in lead I in the presence of a positive QRS is always abnormal
• In a normal ECG, T waves in V5-V6 should always be upright.
• Inversion in lead III or aVL may be normal
• Lead aVF may be slightly negative
• Lead V1 is commonly negative
• Of leads V2-V4, normal inversion is rare in V2, more rare in V3 and most rare in V4
• QRS-T angle > 60 degrees

My interpretation was this: this is a normal ECG of a healthy young thin male.

But it looks abnormal because there are 2 different lead placement mistakes on the same ECG:

1) V1 and V2 were placed too high.  When you see T-wave inversion in lead V2, you should wonder if perhaps it is due to high lead placement.  How can you verify or refute that?  Look at the P-wave in V2: it should be upright.  Here it is negative.  Thus, V1 and V2 were placed too high.  The "ST depression" seen by the computer is in leads V1 and V2 and is a result of lead placement as well; see below that when they are recorded correctly, there is normal variant ST elevation.

2) Limb leads were reversed.  Look at the (limb lead) axis.  It is directly to the right, with tall R-waves in I and aVL.  Yet there are R-waves in V5 and V6.  Although V5 and V6 are slightly different than I and aVL because they are more inferior, they should not look this different.  The depolarization is to the left (V5 and V6), not to the right.  This is why the axis appears to be to the right and why the computer called it left posterior fascicular block.

The patient arrived in his room and still had his stickers on.  I obtained written permission to take a photo of his chest.  Look how high V1 and V2 are:
 Notice also he is a thin young man

I put the leads in the correct position (4th intercostal space) and recorded another ECG, also being certain that the limb leads were not reversed.

Here is the result:

Now it is simply a healthy looking ECG with high voltage (not due to LVH, but normal for a young thin healthy male)
The axis is normal now.
The T-wave is upright in lead V2, as is the P-wave.

The ST depression in V1 and V2 is replaced by normal variant ST elevation.

Interestingly, I forgot to put in the formal read on that first ECG.

Another physician did so, and simply confirmed the erroneous computer interpretation.

I have no idea how it failed to diagnose sinus rhythm.
It is hazardous to simply confirm the computer interpretation!

Here are K. Wang's comments:
1) The computer is calling Atrial flutter/atrial tachycardia, which obviously is wrong.  Computer is usually better than this. Where did the computer go wrong? I see that, in lead l, the negative P wave and the negative T wave occur at about same distance at a rate of about 160/m, which the computer is mistaking as ectopic atrial P waves or the negative component of the flutter waves.
2) Before one calls right axis deviation, always pay attention to the P wave in lead l. If it is inverted, it's either reversed arm leads or dextrocardia. One needs the precordial leads to sort this out. Obviously, a human error of reversing the arm leads is far more common than dextrocardia.

From Sam Ghali:

Steve, Another great teaching case! It’s crazy how commonly V1 + V2 are placed high, precisely where you have shown. I think it’s mostly because it is easier to not remove the shirt, or the bra gets in the way in a woman. Regarding the limb lead reversal, the other key clue that the leads have been reversed is they leave an usual P-wave axis (+ in aVR, - in I & aVL) around 120-150 degrees, coinciding with the QRS axis. I presume this is why the computer did not call Sinus Rhythm! Sam

Comment by KEN GRAUER, MD (7/29/2018):
Short and simple case in which Dr. Smith reviews a “Must Know” Concept — which is ready recognition of Lead Misplacement. The fact that not one — but several physicians apparently missed both of the types of lead misplacement that occurred here — and, that another physician signed off on the grossly inaccurate computer interpretation of the 1st tracing, apparently without even looking at the ECG — is evidence that much work remains to be done in the area of ECG interpretation. Dr. Smith expertly covered the essentials of the ECG diagnosis in this case. I limit my comments to a few additional points. For clarity and ease of comparison — I’ve put both tracings together in Figure-1.

Figure-1: ECG #1 is the original tracing. ECG #2 is after limb lead and chest lead placement were corrected by Dr. Smith (See text).

  • There are many different types of limb lead misplacement. That said, the most common lead mix-up (by far!) — is LA-RA mix-up. When this is done — then the appearance of the QRS complex and ST-T wave in lead I will look like lead aVR typically looks — and vice versa. You can instantly suspect LA-RA mix-up has occurred if you remember that there should never be global negativity (of the P wave, QRS and T wave) in lead I. The only 2 conditions that cause this are: iLA-RA mix-up; and iidextrocardia (which is rare!). You can quickly rule out dextrocardia by looking to see if there is normal R wave progression (as well as making sure heart sounds are on the left). Note in Figure-1, in lead I of ECG #1 that there is global negativity! Even when there has been a huge lateral infarction that produces a large Q in lead I — you will not see global negativity in this lead.
  • The perspective of lead aVR is to look down at the heart from the right shoulder. As a result — this lead generally sees electrical activity as moving away from aVR, which often results in the global negativity normally seen in aVR. At times, you may see a component of positivity in aVR — but you should not see the positive P and QRS complex that is present in aVR for ECG #1.
  • Finally — there is NO upright P wave in lead II of ECG #1. This means that either the rhythm is not sinus — or — there is some kind of lead misplacement.
  • Note in Figure-1 that there is normalization of electrical activity in all 3 of these leads in ECG #2 after limb lead placement has been corrected ( = positive P, QRS and T wave in lead I; global negativity as it should be in aVR; and return of an upright P wave in lead II).
  • PEARL: My favorite “Quick GO-To” reference for the most common types of lead misplacement comes from LITFL (= Life-In-The-Fast-Lane). In addition to the superb user-friendly diagrams and charting in their write-up — I love the fact that you can instantly find this LITFL post by searching on-line for “lead misplacement litfl” — which I have done numerous times when I wanted to find quick answer to the question of which lead got mixed up with which other lead?

Our group surveyed the internet in search of assessing how prevalent chest lead misplacement is. Suffice it to say that even on internet sites purporting to demonstrate “correct chest lead placement” — errors in chest lead placement were disturbingly common. The most frequent of these is placing leads V1 and V2 one or two interspaces too high on the chest. For just one example of the potential clinical impact misplacement of leads V1 and V2 may have — you have no further to look than the ECG Blog post by Drs. Meyers and Smith from yesterday ( = July 28, 2018 You'll see my discussion of this error if you scroll down to the bottom of the page).
  • Recognition that leads V1 and V2 are probably placed too high on the chest is easy! Look for: iA significant negative component to the P wave in leads V1 and V2; iiT wave inversion isolated to leads V1 and V2; iiian rSr’ in V1 and V2; and ivAppearance of the QRST complex in V1 that closely resembles the QRST appearance in lead aVR. Just 2 or 3 of these findings are all that is needed to raise suspicion — which you can then easily check out by repeating the ECG after verifying lead placement. It should be mentioned that there may normally be a slight negative component to the P wave in lead V1 — and, that with left atrial abnormality, this negative component in V1 may become fairly large. But one does not usually see the deep, all negative P waves that appear in V1 and V2 of ECG #1. And one does not typically see a nearly identical appearance in V1 and V2, with negative P waves and T inversion that also looks nearly identical to what we see in lead aVR in ECG #2, once the limb leads were correctly placed.
  • PEARL: My favorite quick reference regarding placement of leads V1 and V2 too high on the chest, is the Letter to the Editor by Javier GarcĂ­a-Niebla (Rev Esp Cardiol 61(10):1109-1110, 2008).

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