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?
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.
9. II, III, and aVF also frequently have T-wave inversion.
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.
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.
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 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”)
Here are many more cases of proven BTWI from this blog: