Download Inappropriate and Confusing Electrocardiographic Terms

Journal of the American College of Cardiology
© 2011 by the American College of Cardiology Foundation
Published by Elsevier Inc.
Vol. 57, No. 15, 2011
ISSN 0735-1097/$36.00
doi:10.1016/j.jacc.2010.11.040
VIEWPOINT AND COMMENTARY
Inappropriate and Confusing
Electrocardiographic Terms
J-Wave Syndromes and Early Repolarization
Borys Surawicz, MD,* Peter W. Macfarlane, DSC†
Indianapolis, Indiana; and Glasgow, United Kingdom
A plea is made for not using in publications the terms J-wave syndromes and early repolarization until such
terms are properly defined by appropriate task forces established by recognized authorities. The currently used
electrographic terminology, including J-point elevation, meets our needs. (J Am Coll Cardiol 2011;57:1584–6)
© 2011 by the American College of Cardiology Foundation
The term J-wave syndromes appeared first in a paper by Yan
et al. (1) and is a title of a contemporary review by
Antzelevitch and Yan (2). In Table 1 of the review (2), the
authors list 4 inherited and 2 acquired types of J-wave
syndromes. The inherited types are: early repolarization
(ER) type 1, where the ER pattern is located in the lateral
leads; type 2, where the ER pattern is in the inferior or
inferolateral leads; type 3, where there is global ER; and
type 4 is the Brugada syndrome. The 2 acquired types are
associated with ventricular tachycardia (VT) or ventricular
fibrillation (VF); 1 is ischemia mediated, and the other
hypothermia mediated.
What Does “J” Stand for
in Cardiac Electrophysiology?
J-wave. The J-wave or Osborne wave (3) frequently appears in the electrocardiogram (ECG) during deep hypothermia (4). It is a low-frequency deflection at the end of the
QRS complex, morphologically similar to the P-wave, and
is usually present in all 12 ECG leads. It is not clear whether
it represents ventricular depolarization or early repolarization. A similar deflection may be present in patients with
hypercalcemia, Brugada syndrome, and in several other
conditions (4).
J-point elevation. The J (junction) point marks the end of
the QRS complex, and is often situated above the baseline,
particularly in healthy young males. It may also be elevated
as a result of injury currents during acute myocardial
From the *CARE Group, Indianapolis, Indiana (retired); and the †Institute of
Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United
Kingdom. Dr. Surawicz has reported that he has no relationships to disclose. Dr.
Macfarlane is a consultant to industry in respect of provision of advice on electrocardiography, and his university receives grants from industry to support research into
ECG interpretation and electrocardiography in general.
Manuscript received August 12, 2010; revised manuscript received November 2,
2010, accepted November 8, 2010.
ischemia and pericarditis, as well as in various other patterns
of both normal and abnormal ECGs.
Defining normal limits of J-point elevation in millivolts
above the baseline requires consideration of several variables, such as the lead, heart rate, age, sex, race, and overall
amplitude of the QRS complex (see the following text). The
absence of such data makes it difficult to evaluate the
significance of increased J-point elevation found in survivors
of primary ventricular fibrillation (5).
End of QRS complex. One of the problems in measurement of the QRS duration is defining the J-point when the
transition of the QRS complex into the ST segment is not
sharp but gradual because of an overlap of ventricular
depolarization and repolarization at the end of the QRS
complex. In a method proposed by Lepeschkin and Surawicz (6) to define the J-point when the QRS-ST junction is
not sharply demarcated, but curved (wide QRS-ST junction), the discrepancy of repeated measurements of the QRS
interval reached 40 ms.
In current clinical practice, the measurement of the QRS
interval is performed by automated methods of analyzing all
12 leads simultaneously recorded in digital form. The
automated technique appears to decrease the error of measurement. However, the International Electrotechnical
Commission tolerance limits in measurement of QRS
duration in biological (real) as opposed to calibration and
analytical ECGs are ⫾ 10 ms (7).
Elevation of J-Point and ST Segment
Above the Baseline in Normal ECGs:
Age, Sex, and Race Differences
Differences between ventricular repolarization in the ECGs
of males and females have been known for a long time (8).
Bidoggia et al. (9) found that the amplitude of the J-point
and the angle between the ST segment and the baseline (ST
Surawicz and Macfarlane
Inappropriate ECG Terms
JACC Vol. 57, No. 15, 2011
April 12, 2011:1584–6
angle) were the best discriminators between the ECGs of
males and females.
Surawicz and Parikh (10) examined the previously mentioned 2 variables in normal ECGs of 529 males and 544
females, age 5 to 96 years. They inspected only the 4
precordial leads: V1 through V4. The pattern was considered
as female when the J-point amplitude above baseline was
⬍0.1 mV in each of the 4 leads, and as male when the
J-point was ⬎0.1 mV and the ST angle was ⬎20° in at least
1 of the 4 leads.
In females of all ages, the male pattern was present in ⬍20%
subjects, whereas in males, it was present in 60% at the age 5
to 7 years, increased at puberty, reaching 91% in the age group
of 17 to 24 years, and gradually declined to the same level as in
females after the age of about 60 years.
Macfarlane (11) published age- and sex-based normal
limits of J-point (STJ amplitude). In a more recent publication in collaboration with Katibi and others (12), he
pointed out that STJ is more elevated in African males
living in Nigeria than in Caucasian males.
We provide this information to explain the importance of
lead, sex, age, and race in the evaluation of the significance
of J-point elevation and the angle of ST segment takeoff
during early repolarization.
The Tale of 2 Js
It is curious that the letter J in cardiac electrophysiology
defines 2 unrelated and totally different events. One is a
rarely encountered, several millimeter long, slow deflection
of uncertain origin at the end of the QRS complex,
originally identified in hypothermia. The second is a point
in time, marking the end of QRS and the onset of the ST
segment that is present in all ECGs. The differentiation
between the meanings of the 2 Js is so great that confusion
is unlikely.
What Is Early Repolarization?
The repolarization in ventricular myocardial cells may or
may not begin with a notch attributed to transient outward
current (Ito), and is followed by a plateau (phase 2) and rapid
phase 3 (13). To our knowledge, the course of repolarization
has not been separated into an early and late phase by a
dividing line. The widely used term early repolarization has
been generated by electrocardiographers to describe, in most
cases, a normal variant of ST-segment elevation. The
American College of Cardiology (ACC)/American Heart
Association (AHA)/Heart Rhythm Society (HRS) recommendations for the standardization and interpretation of the
electrocardiogram (14) include a statement that the term
early repolarization is used frequently to characterize a
normal QRS-T variant with J-point elevation. In the
textbook Chou’s Electrocardiography in Clinical Practice, the
term early repolarization is featured as a normal variant that
lacks precise definition (4). This is because it is an early
portion of the ST segment of undetermined duration.
Moreover, the normal limits of
amplitude depend on the lead,
total QRS amplitude, age, sex,
and race.
Other Interpretations of the
Term Early Repolarization
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Abbreviations
and Acronyms
ACC ⴝ American College of
Cardiology
AHA ⴝ American Heart
Association
ECG ⴝ electrocardiogram
ER ⴝ early repolarization
Antzelevitch and Yan (2) referred
HRS ⴝ Heart Rhythm
to a 1961 paper by Wasserburger
Society
and Alt (15), who defined ER as
an elevated takeoff of the ST segment varying from 1 to 4 mm from the isoelectric line,
accompanied by downward concavity of the ST segment
and symmetrical T-wave.
Kimbaris and Philips used the term early repolarization in
the title of their 1976 paper (16), but concluded that it was
a normal variant. However, Gussak and Antzelevitch (17)
pointed out that ER has a potential for arrhythmogenicity.
Haissaguerre et al. (18) reported that ER is present in
31% of 206 subjects who were resuscitated from cardiac
arrest caused by idiopathic ventricular fibrillation, versus 5%
in control subjects (p ⬍ 0.001). Early repolarization in this
study was defined as an elevation of the QRS-ST junction
of at least 0.1 mV from baseline in the inferior or lateral
leads manifested as QRS slurring or notching. Similarly
assessed was the risk of ER in other studies. Tikkanen et al.
(19) found that among 630 middle-aged subjects with ER
in the inferior leads, ST-segment elevation exceeded 0.2
mV in 36 subjects (0.3%). This finding was associated with
an increased risk of cardiac death (p ⬍ 0.001).
Watanabe et al. (20) found ER in 63% of 37 patients with
short QT and associated sudden death (SQT syndrome).
Ghosh et al. (21) reported that in 2 patients with aborted
sudden death, ER was associated with large local dispersion
of repolarization. In a recent prospective study of 2,063
subjects between 35 and 74 years of age, prevalence of ER
was 18.5%, and ER was associated with increased cardiovascular mortality (22).
Morphology of ER
In publications in which the ER pattern (mostly in leads III,
aVF, and V4 to V6) is identified by an arrow (19,20,22), the
12-lead ECGs were recorded at the speed of 25 mm/s.
When the figures were magnified, it was possible to see that
the arrows pointed either at a slow descent of the R-wave
toward baseline (reminiscent of poor frequency response of
the recorder), or at notches before or after the approach of
R descent to the baseline. In 1 case, the terminal deflection
resembled that of an incomplete right bundle branch block.
Unfortunately, the deflections marked as ER in the
aforementioned studies were not synchronized in several
leads, not recorded at higher paper speeds, and not examined by body surface mapping or vectorcardiography. Thus,
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Surawicz and Macfarlane
Inappropriate ECG Terms
it is not possible to know whether the alleged ER is indeed
an abnormality of repolarization.
Wellens in his editorial comment (23) on the study of
Haissaguerre et al. (18) questioned “. . . whether the described abnormality at the end of QRS complex is indeed
early repolarization, or rather delayed activation of the
inferolateral wall.” The origin of the terminal QRS portion
was debated in subjects with the Brugada syndrome (24).
Concluding Remarks
The electrocardiographic terminology stemming from the
end of the 19th and the beginning of the 20th century has
undergone few modifications when scrutinized by a succession of task forces appointed by the ACC or the AHA from
1978 (25) onward. The terminology, including ST-segment
elevation, was recommended by the most recent task force of
the AHA/ACC/HRS, published in 2009 (14).
In our opinion, the established ECG terminology is sufficient to define clearly and accurately all normal and abnormal
ECG patterns, and therefore terms other than the existing
electrocardiographic nomenclature, such as J-wave syndrome
and early repolarization are superfluous and confusing.
The J-wave was described originally in the setting of deep
hypothermia, where it was often a precursor of ventricular
fibrillation. The J-wave is very seldom encountered under
other circumstances.
The J-point exists in all ECGs but does not need to be
singled out in the ECG reports describing ST-segment
deviations because it is a component of the ST segment.
The terms early and late repolarization are synonymous
with phases 2 and 3 of the transmembrane action potential.
In the ECG, they correspond to ST segment and T-wave.
Unlike ER, the duration and the amplitude of the ST
segment are measurable in millimeters and millivolts, respectively. This means the term ER is not needed in clinical
electrocardiography. The terminal QRS abnormalities can
be adequately described as fragmentation, slurring, or
notching.
We have refrained from discussing the suggestions that
terminal QRS abnormalities in the quoted references 18 to
22 mark substrates for ventricular arrhythmia, but acknowledge the need to investigate such correlations. This will
probably not change the existing ECG terminology.
Reprint requests and correspondence: Dr. Borys Surawicz, Care
Group, 8333 Naab Road, Indianapolis, Indiana 46260. E-mail:
[email protected].
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Key Words: early repolarization y electrocardiogram y J point.