Wednesday, January 2, 2019

15 yo AAM with ST Elevation and T-wave Inversion. Hypertrophic Cardiomyopathy or Normal ("Variant")?

Is this normal or hypertrophic cardiomyopathy (HOCM)?


The mother of a 15 yo African American male brought her son to the clinic for a sports physical.  There was a family history of sudden death.  The clinic recorded this ECG and was alarmed:

Should the physician be alarmed by this?












Answer: No.

This is almost certainly a normal ECG in an African American adolescent male.  There is some remote possibility of HOCM, but the morphology is classic for a normal variant.  Even calling it a normal variant is an ethnocentric terminology, as if the white normal is the true normal.  This is normal normal for an African American youth.

The high voltage is typical of a young athletic thin-walled male.

The mother was alarmed and brought the boy to the ED, where I saw him and recorded this ECG, which is slightly different but within normal day to day variation:

There is also "Sinus arrhythmia" (varying sinus rate)
V4 is classic benign "variant" and is the most recognizable lead in this ECG morphology.

This has been called "Benign T-wave Inversion" BTWI) in this blog, as Chou named it in his textbook.


BTWI is a normal variant associated with early repolarization.  K. Wang studied it.  He reviewed ECGs from all 11,424 patients who had at least one recorded during 2007 at Hennepin County Medical Center (where I work) and set aside the 101 cases of benign T-wave inversion.  97 were black.  3.7% of black men and 1% of black women had this finding.  1 of 5099 white patients had it.  Aside from an 8.8% incidence (9 of 109) in black males aged 17-19, it was evenly distributed by age group.

I have reviewed these 101 ECGs, and what strikes me is:

1. There is a relatively short QT interval (QTc less than 425ms)  
2. The leads with T-wave inversion often have very distinct J-waves.
3. The T-wave inversion is usually in leads V3-V6 (in contrast to Wellens' syndrome, in which they are V2-V4)
4. The T-wave inversion does not evolve and is generally stable over time (in contrast to Wellens', which always evolves). 
5. The leads with T-wave inversion (left precordial) usually have some ST elevation 
6. Right precordial leads often have ST elevation typical of classic early repolarization
7. The T-wave inversion in leads V4-V6 is preceded by minimal S-waves
8. The T-wave inversion in leads V4-V6 is preceded by high R-wave amplitude
9. The QRS is not at all widened.
10. II, III, and aVF also frequently have T-wave inversion. 

HOCM may have some of these features, but another one which distinguishes HOCM is evidence of septal hypertrophy, with either or both of tall (even needle-like) R-wave in V1 and/or deep (and needle-like) S-wave in V6.  I have provided 2 examples of this below.


Case continued:

We performed a bedside echo:


Parasternal long axis - normal



Parasternal Short Axis -- normal



A formal contrast echo done later and read by a pediatric cardiologist was also normal.

Learning points:

While it is possible that such an ECG may represent HOCM, the vast majority of the time it is a normal finding in an African American Male under age 20-25, and even older.

I believe that there are distinct differences between the ECGs of HOCM and those of BTWI because, from the examples I have seen, the morphology is subtly but clearly different.

Below are some ECGs for comparison: The bottom two ECGs below are HOCM that are purported to mimic benign T-wave inversion.  I think they look distinct.  (These references come to me courtesy of Brooks Walsh):

The first two are from this publication: Drezner JA et al.  Abnormal electrocardiographic findings in athletes: recognising changes suggestive of cardiomyopathy.  Br J Sports Med 2013;47:137-52.
https://bjsm.bmj.com/content/bjsports/47/3/137.full.pdf

This one is presented as normal, and I agree:
This is normal.  This journal states that if there were T-wave inversion in V5/V6, then one could not say it is normal, and one should be worried about HOCM.
However, benign T-wave inversion frequently has T-wave inversion in V5/V6; therefore, this finding is certainly not specific to HOCM.

This one is HOCM:
This is a case of HOCM
To me this looks clearly different from the one above.
Some important features that differentiate:

1. R-wave is much more prolonged; it is not a very narrow R-wave
2. QT interval is significantly longer.
3. There is no S-wave in V4
4. There is no J-wave in V4
5. No elevated J-point in V2, V3


This HOCM ECG comes from this publication: Schnell F et al. The Recognition and Significance of Pathological T-Wave Inversions in Athletes.  Circulation 2014;131:165-173.

This is a case of HOCM
This one also looks clearly different:
1. No S-wave in V3 or V4
2. No J-wave in V4
3. Neither S-wave nor J-wave in V3 ("Terminal QRS distortion")

HOCM with needle R-waves in V1 and/or needle S-waves in V6.  

These are both courtesy of Life in the Fast Lane. https://litfl.com/hypertrophic-cardiomyopathy-hcm-ecg-library/
HOCM with needle tall R-wave in V1.  In other respects, it looks a lot like BTWI, but this R-wave is a distinguishing feature.

Here is one with a large R-wave in V1 and deep needle like S-waves in V5, V6.
This one does not look anything like BTWI.



Here are many more cases of proven BTWI from this blog:









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Comment by KEN GRAUER, MD (1/2/2019):
-----------------------------------------------------------
I love this post by Dr. Smith — because it is clinically experiential. Based on a comprehensive review by Dr. K. Wang of no less than 11,424 patients — a group of 101 cases of benign T wave inversion was identified. Dr. Smith’s 10 Observations regarding these 101 tracings are highly relevant clinically and most noteworthy. For clarity regarding the case presented here — I’ve reproduced the first 2 ECGs shown above (Figure-1). The Questions raised are: #1Should the treating clinician be alarmed by the two ECGs in Figure-1?; and#2Are these tracings suggestive of HCM ( Hypertrophic CardioMyopathy)? Addressing these issues and incorporating the PEARLS I abstract from Dr. Smith’s observations, I’d add the following thoughts:
  • While hard to say “never” — it’s tremendously helpful to first and foremost consider the clinical setting of ECG #1 done in this case: This tracing was obtained from an asymptomatic 15yo African American male who presented to the clinic for a sports physical. Given this clinical setting, cause for “alarm” in the form of concern for an acute ongoing cardiac event is exceedingly unlikely no matter how “worrisome” ST-T wave abnormalities may appear. As is so often the case when interpreting ECGs — the clinical History is KEY.
  • Seemingly benign ST-T wave repolarization abnormalities are common ECG findings — especially among young African American males. Although at first glance, the appearance of some of these ST-T wave abnormalities may indeed be alarming — there is a characteristic “look” to most of these tracings, that with experience becomes quite recognizable.
  • Pay attention to the QT interval. Benign repolarization tends to have a relatively short QTcIF the QTc is clearly prolonged — this is helpful, and favors pathology (Caution: A normal QTc does not rule out a pathologic cause).
  • Pay attention to the width of the QRS complex. Benign repolarization tends to have a narrow QRS. IF the QRS is at least slightly widened — this is helpful, and favors pathology (Caution: Slight-to-moderate QRS widening may at times be seen in patients without underlying heart disease).
  • With benign repolarization — Leads with T wave inversion often have prominent (distinct) J waves. (Caution: J waves are not always seen with benign repolarization; and J waves can occur at times when there is a pathologic cause).
Figure-1: The 2 ECGs performed on the 15yo African American male in this case (See text).
==========================
Regarding the 2 ECGs in Figure-1:
I didn’t think the findings in ECG #1 were acute. However, I thought the appearance of this tracing in the anterior chest leads was highly unusual. I suspected lead malposition, at least of leads V1 and V2 because:
  • There is an uncharacteristically deep S wave in lead V1 of ECG #1 — especially in view of the relatively tall R wave in this lead, and the lack of a deep S wave in lead V2.  In addition, the markedly coved ST elevation in V1 just looks “out of place”.
  • Lead V2 manifests a bizarre 4-phase QRS complex (rSr’S’) — with an unexpectedly low amplitude ST-T wave compared to the much larger ST-T wave deflections in neighboring leads V1 and V3. In a word, QRST morphology in lead V2 looks nothing like a “transition lead”, that should show intermediate QRST morphology to what we see in V1 and V3.
The repeat ECG done in the ED ( = ECG #2) supports my initial impression that there was lead malposition of at least V1 and V2 in ECG #1. Note that while there has been little appreciable change between these 2 tracings in either the limb leads or in leads V4-thru-V6 — the appearance of the first 3 chest leads (ie, leads V1, V2 and V3) is markedly different in ECG #2, compared to what it was in ECG #1. There is now a much more normal progression of QRST appearance as one moves across the chest leads. Due to this technical shortcoming — I won’t comment further on ECG #1.
  • ECG #2 is most probably normal for age. As per Dr. Smith — large amplitude R waves are often seen in younger individuals who do not have chamber enlargement. Prominent J waves are seen in several leads (leads I, V4-6), with the lead showing greatest J-point ST elevation and greatest T wave inversion also manifesting the most prominent J wave.
==========================
QUESTION: Are the findings in ECG #2 suggestive of HCM? Was an Echo indicated in this case?


ANSWER: The mother of this 15yo boy was concerned enough to bring her son to the ED for evaluation. There was a family history of sudden death. These 2 factors alone justify doing an Echo — which turned out to be completely normal.

COMMENT: The answer to the above question regarding HCM is far from simple. HCM is estimated to occur in ~1 in 500 young adults, making it among the most common inherited cardiac disorders. It is the most common underlying cause of sudden cardiac death (SCD) in asymptomatic young individuals. The condition is easily ruled in or ruled out on echocardiography — so obtaining an Echo is clearly indicated whenever a screening ECG shows any findings potentially suggestive of HCM. That said — there will by many false positive ECGs that turn out not to be due to HCM (increased cost of getting Echos on these subjects …) — and even if found, one will still be left with sorting through the large “spectrum” of HCM disorders encompassing “lower risk HCM” with modest or moderate hypertrophy but without obstruction, vs higher-risk obstructive forms of HCM.
  • Although the majority of patients with HCM do not have a normal ECG — the ECG is far from ideal as a screening tool. There are a variety of possible ECG findings that may be seen in patients with HCM. These include increased QRS amplitude; large septal Q waves; tall R wave in lead V1; abnormal ST-T wave abnormalities (not obeying the more benign characteristics in Dr. Smith’s observations above); conduction defects (ie, LBBB, IVCD); WPW; cardiac arrhythmias. The problem is that none of these findings are specific for HCM.
  • The patient in this case apparently had a screening ECG done as part of a routine sports physical. The obvious goal of a screening ECG is to reduce the incidence of sudden death among asymptomatic, healthy athletes not suspected of having a cardiac disorder. In addition to HCM — other entities that might be suggested by an abnormal ECG include congenital long QT syndrome, Brugada syndrome, and RV dysplasia (all very important, but very rare syndromes) — leaving greatest potential benefit to accrue from detecting HCM. That said, the approach to screening remains highly controversial with lack of consensus (and beyond the scope of my discussion here). Who should be screened? It is probably “wishful thinking” that random ECG screening of millions of young US athletes will detect potentially preventable cardiologic entities in a cost-effective manner. Getting an Echo on all such young athletes (to rule out possibility of HCM) would seem to be cost-prohibitive. And then, what about potential harm from false positive ECGs? (ie, unnecessarily prohibiting exercise … ).
==========================
BOTTOM LINE: Positive service was provided to the patient and his family in this case by Dr. Smith. The normal Echo confirmed clinical suspicion that ECG #2 was indeed normal for age. This is clearly reassuring given the positive family history of sudden death in this case.
  • That said — the unfortunate clinical reality is that no approach to this issue is perfect. There still are cases in which despite our best screening efforts, a young athlete drops dead suddenly every so often during vigorous athletic activity (estimated to occur every 1-4 times per 100,000 person-years).
  • DON’T FORGET to ASK these QUESTIONS: After ensuring no obviously pathologic heart murmur or other concerning findings on exam — ASK the Patient: iDo you ever feel lightheaded during exercise?; andiiIs there anyone in your family who dropped dead suddenly (unexplained) at an early age (probably defined as under 55)? A “YES” answer to either of these questions should initiate automatic referral to your friendly cardiologist colleague.


2 comments:

  1. A good tracing to illustrate and discuss the entity.

    ReplyDelete
  2. sir ur post r really very helpful love from india

    ReplyDelete

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