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Inverted T waves in the precordial electrocardiogram of normal adolescents
Invsrted
T wavm
in the precordial
eleckocardkqp-am
d norm-d
#es
Norman S. Blackman, M.D.* Lawrence Kuskin, M.D.** New York, N. Y.
S
harp19 inverted T waves in the precordial electrocardiogram have been reported in patients without evidence of clinical heart disease. Inversion of the T waves in Leads V, through Vq have been found so frequently in normal children that it. has been called “the normal juvenile pattern.” In addition, inversion of the T waves over isolated areas of the precordium, as in V, or Vq areas, have been reported in healthy adults. Inversions of the precordial T waves similar to both of the above-mentioned patterns have been reported in normal adult Negroes,leg as well as in Caucasians.*r3f9-11 Findings such as these in adults without heart disease have been a source of deep concern because the patterns are alarmingly similar to those often found with acute myocardial disease. No satisfactory explanations have been given for these observations. Some possibilities which have been suggested include: the influence of a relative deficiency of potassium,12~13 the effects of aging,14 anxiety,‘5 fear,16J’ cooling of the precordial region,lOrls influence of the intake of food,lg rotation of the heart in a clockwise position,20 impact of the cardiac From
apex against the chest wa11,21 local pericardial or myocardial disease,21 drinking of ice water,22 differences in myocardial hyperventilation,13J3s24 blood suPPlY,1o sympathetic - parasympathetic imbalance,10,26 posture, 2os27the effects of respiration,26-2g and the influence of local electrical potentials.30-33 We have studied the form34 and the effects of respiration on the T wave.35 Thus, we were interested in finding inverted precordial T waves in the electrocardiogram of a clinically normal adolescent boy. Because of these findings he was prohibited from athletic activities, although he was an outstanding athlete. However, when he took a deep breath and held it, the inverted T waves in V4 immediately became upright and normal in appearance. The sudden change from an apparently abnormal to a familiar, normal-appearing pattern suggested that the changes were not evidence of myocardial disease. Within a short period of time, 4 similar cases came to our attention. The following is a presentation of our findings. The factors which may be responsible for the dramatic changes in the ECG are discussed.
the Cardiac Consultation Service, Bureau for Handicapped Children. New York City Department of Health, New York. N. Y. Received for publication June 3, 1963. *Clinical Assistant Professor of Medicine, State University of New York Downstate Medical Center, Brooklyn, N. Y.; Cardiac Consultant, New York City Department of Health; Associate Attending Physician, The Brooklyn and The Beckman-Downtown Hospitals. Address: 100 Remaen St., Brooklyn 1, N. Y. **Clinical Assistant Professor of Environmental Medicine and Community Health, State University of New York Downstate Medical Center. Brooklyn, N. Y.; Chief, Cardiac Consultation Service, New York City Department of Health, Brooklyn; Attending Pediatrician and Chief of Pediatric Cardiology Clinic, Maimonides Hospital, Brooklyn, N. Y.
304
Vohme Number
67 3
Inverted
T waves in precordial
Findings The clinical features of our 5 cases, summarized in Table I, are within normal limits. Initially, all patients had been referred for evaluation of a systolic heart murmur which was found on a routine physical examination at school. Although equal numbers of males and females are seen at our clinic, all of our patients were males. Four were Negroes, two of whom were trained athletes. The electrocardiographic tracings (Figs. l-5) show seemingly abnormal inversion of the T waves in Va or Vq precordial leads, with “cove-planing” of the S-T segments in Cases 2, 3, 4, and 5. The lower tracings were continuously recorded (except in Fig. 4) to show the rapid changes in the tracing when the subject took a deep breath. With this maneuver the seemingly abnormal S-T segments and T waves quickly became normal in appearance. The QRS contour, however, was not significantly changed, except for some changes in the voltage. This would seem to indicate that the reversal in the direction of the T waves as a result of the inspiration is not secondary to alterations in the QRS complex
Table
Case
I. Summary
Age
of clinical
Race
Sex
Discussion
An electrode placed on the precordium is displaced anteriorly and superiorly by the movement of the chest wall on deep inspiration. At the same time the heart is displaced inferiorly as it follows the descent of the diaphragm. This results in a shift in the spatial relations between the precordial electrode and the local area of underlying epicardial surface. Jn addition, other changes occur which may be of profound significance. The anatomy of the left lung and reflexions of the pleura are such that an area overlying the anterior surface of the heart is known as “the cardiac notch.‘lS1 Here the anterior surface of the heart is covered by a minimum of lung tissue or none at all (see Figs. 6 and 7). This is normally under the precordial area between Vz and Vq electrode positions on the chest. In this region, therefore, the anterior surface of the heart is in closest approximation to the chest wall.** However, with deep inspiration there is ample room for aeration and expansion of the left lung anteriorly and medially to cover much of the anterior surface of the heart. This removes the heart from its close proximity to the chest wall.
features of 5 normal adolescentswith inverted precordial T waves
Past h&ory
Performance
(YY.)
1.
G.R.
305
ECG of normal adolescents
BP (mm.
Murmurs
Fluo~osco~y
Hd
18 Negro M No cardiac symptoms
Varsity basket- 100/60 Innocentapical Upperlimit of norball team systolic ma1in size; slight nence
promiof right
ventricle 2.
J.S.
16
Negro
M
Occasional
Normal
11.5/80
Innocent systolic
apical
Heart normal in size and shape
105/70
Innocent systolic
apical
Heart normal in size and shape
130/80
Innocent systolic left sternal border
Heart normal in size and shape
122/68 Innocent apical
Heart normal in
precordial distress
vague
3.
B.B.
14
White
M
No cardiac symptoms
Normal
4.
A.C.
15
Negro
M
No cardiac symptoms
Normal track
5.
F.D.
14
Negro
M
No cardiac symptoms
Normal
varsity team
systolic
size and shape
Fig. I. ECG tracing of a 11or1na1 1%year-old .\egro boy, bvith illvcrtcd ‘1‘ wa\ es in Lead V: and low-voltage ‘1‘ waves in Lead \‘;. The lower two tracings are rontinuous recordings which show the immediate effect of deep inspiration.
Fig. 2. ECG tracing of a normal 16-year-old Negro boy, showing diphasic T waves in Leads VP, V1, VS; inverted T waves in Lead VI, with “cove-planed” S-T segments. The lower tracing (taken at reduced standardization) shows Lead VS continuously recorded during normal respiration and after the taking of a deep inspiration.
1'ohm? Ntrmbrr
67 3
Inverted T wuves in
precordial
ECG of
normal
adolescents
Fig. 3. ECG tracing of a normal 14-year-old white boy, showing the effects a deep inspiration upon the contours of the S-T segments and the T waves Leads VZ and Va.
of in
Fig. 4. ECG tracing of a normal 15year-old Negro boy, showing the effects of a deep inspiration on the S-T segments and inverted T waves in Leads V? and VEr. (The lower tracing is not continuous because of wandering of the base line.)
307
.4m. Heart I. March, 1964
Fig. 5. Electrocardiographic tracing of a normal 14-year-old Negro boy. The continuously recorded lower tracings show the effect of a deep inspiration upon the contours of S-T segments and T waves in Leads \1’3 and V,.
When the chest is fluoroscoped in the lateral view, the heart usually can be observed to follow the descent of the dia-
Fig.
6. Note
the cardiac
notch.
(After
Spalteholz.5’)
phragm on deep inspiration. The retrosternal field becomes broader and lighter in appearance. In some cases the chest wall separates from the heart sufficiently for one to see between them.49 Obviously, this space must be occupied by aerated lung tissue interposed between the anterior epicardial surface and the posterior surface of the sternum. It is inaccurate to consider the body tissues as homogeneous electrical conductors. Muscle tissue is an excellent conductor, blood has a higher resistivity,*’ and fully aeruted lung tissue is a relatively poor conductor of electrical currents.45-47 The heart may be considered to be more or less surrounded by aerated lung tissue which tends to insulate the local electrical potentials on its surface from the chest electrodes. Inverted precordial T waves are sometimes recorded from normal hearts in VI through Vq on the surface of the chest. It is pertinent, therefore, to consider the nature of the underlying electrical potentials found on the anterior epicardial surface
Volume Number
67 3
Inverted
T waves in @cordial
of the normal human heart. These have been studied by Groedel,36 Carouso,37 J ouve,38-40 Miyaji,l’ and Barbato.42T43 Except for the last named, these authors were primarily interested in the characteristics of the QRS. Dissimilarities are observed in the T waves when direct epicardial leads are compared with precordial leads. Fig. 8 is a reproduction of Barbato’s tracings obtained directly from the epicardial surface of a normal 43-year-old white man. For comparison, the curves obtained from the surface of the anterior chest wall of the same patient are also illustrated. The direct epicardial leads show local areas of sharply inverted T waves scattered over much of the anterior surfa.ce oj’ the heart. These were not recorded by the electrodes placed upon the precordium in VZ through V4 positions. Negative T waves are closely adjacent to and intermingle with areas of positive T waves. In such closely adjacent areas of the exposed heart, T-wave negativity could hardly be due to local differences in surface temperature.
Fig. 7. Cross section of Appleton-Century-Crofts.)
of chest
and V leads.
(From
ECG of normal adolescents
309
It seems that the orderly progression of upright T waves usually recorded in normal adults on the surface of the chest does not accurately correspond to those found on the local epicardial surface just underneath the electrodes. Our adolescent patients may be presumed to have the anatomic structure of heart, lungs, and chest wall intermediate between that of a child and an adult. Two were trained athletes with welldeveloped musculature and the ability to maximally ventilate their lungs far beyond that of a young child or an untrained adult. When they took a deep inspiration, the anterior chest wall moved a substantial distance away from the anterior surface of the heart, carrying with it the precordial electrodes placed on its surface. At the same time, the heart was displaced inferiorly with the descent of the diaphragm. Aerated lung tissue, usually minimal or absent over the area of “the cardiac notch” during quiet respiration, became greatly expanded both anteriorly and medially.
Eycleshymer
and Shoemaker,48
by permission
3 10
Blackman
recordibl
Fig. R. Comparison normal 43-year-old
chest
and h-uskipi
leads
of epicardial and chest leads in a white man. (After Barbato.43)
This tissue, a relatively poor conductor, was then interposed between the anterior surface of the heart and the chest wall. This may have resulted in the distortion of inverted T waves normally present in local areas on the epicardial surface of the heart. In children, and in some adolescents, the precordial electrodes (Vt-V,) are in close proximity to the heart. Therefore, they act chiefly like electrodes placed directly on the surface of the heart (direct electrodes). On deep inspiration, however, these electrodes became electrically distant, due to insulation by the interposition of aerated lung tissue. As a result, the same electrode may be only slightly influenced by the local epicardial potentials, and thus acts chiefly like a distant electrode. This hypothesis could explain the sudden reversion of the inverted T waves (exagger-
3tecl intrinsic effect) to T \33ves that were upright and normal (csaggeratc4 extrinsic effect). The so-called juvenile T-wave pattern may also be due to the exaggerated effect of local negative T-wave potentials normally present in certain areas on the anterior epicardial surface. These negative potentials can be transmitted to the anterior chest surface because of their closeness to and lack of insulation from this surface in a child. With growth, the chest wall becomes thicker, and the lurqgs cover more thoroughly the anterior surface of the heart. These changes with growth tend to insulate the local negative epicardia1 T waves. The upright T waves usually found in normal adults in Vz-V, nlust, therefore, be a result of predominantly extrinsic electrical potentials. By taking a deep inspiration, our adolescent patients (intermediate between childhood and adulthood) may have acutely simulated some of the anatomic changes in the heart-lung relations that normally occur only with growth and maturity. “Isolated areas of precordial T-wave negativity” have been recorded in normal adults on occasion.21 Such observations cannot be esplained on the basis of the precordial electrodes acting solely as distant electrodes, nor by vectorial concepts. Esaggerated local electrical proximity effects on the chest electrode by the normally present negative T potentials sometimes present on the surface of the heart are a reasonable esplanation for these observations. Their occurrence in some adults may be a result of unusually thin chest walls and,,‘or underdevelopment of the lungs in such individuals. It is difficult to estimate the importance of the changes in the spatial relations between the heart, lungs, and the electrode on the chest wall as a result of a deep inspiration. That the effects on conduction are probably considerable is suggested by the fact that in 3 of the 5 subjects the QRS comples became decreased in voltage after the taking of a deep, held inspiration. Despite this, the pattern of the QRS was altered only slightly or not at all. This may indicate that the shift in the heart and the chest electrode relative to each other in space was not great. The lack of persistence
Volttme 67
Inverted 1’ waves in prccordial ECG of normal adolescents
Number 3
of the abnormally
appearing
S-T segments and the negative precordial T waves when the electrode was lifted from the proximity of the epicardial surface by the deep inspiratory effort is worthy of note. Summary
and
conclusions
We have presented 5 cases of normal adolescent boys who had abnormally appearing negative precordial T waves accompanied in some instances by “cove-planed” S-T segments. The findings are similar to those often associated with acute, severe myocardial disease. These deviations became quite normal in appearance when the subjects took a maximum, held inspiration. An attempt has been made to explain our findings on the basis of known anatomic relations between the heart, lungs, and chest wall, on knowledge of the electrical conduction properties of tissues, and on the nature of electrical potentials found directly on the anterior epicardial surface of the heart. In addition, these have been offered as possible explanations for other unexplained electrocardiographic observations (i.e., the “negative juvenile T-wave pattern” found frequently in normal children, and the “isolated areas of precordial T-wave negativity” found occasionally in normal adults). When negative precordial T waves are recorded from otherwise normal adolescents or adults, the importance of an esaggerated local proximity effect should be considered. The immediate reversion of these seemingly abnormal findings to normal by the simple expedient of taking a deep, held inspiration should be considered additional evidence of their benignity. REFERENCES 1. Ashman, R.: An electrocardiographic study of Caucasians and Negroes, Tri-State M.J. 13:2686,1941. 2. Littman, D.: Persistence of the juvenile pattern in precordial leads of healthy adult Negroes, AM. HEART J. 32:370, 1946. 3. Littman, D.: Abnormal electrocardiograms in the absence of demonstrable heart disease, Am. J. Med. 5:33?, 1948. 4. Keller, D. H., and Johnson, J. B.: The T wave of the unipolar precordial electrocardiogram in normal adult Negro subjects, AX HEART J. 44:494, 1952. 5. Grusin, M. B.: Peculiarities of the African’s electrocardiogram and the changes observed in serial studies, Circulation 9:860, 1954.
311
6. Wasserburger,R. H.: Observationson the “juvenile pattern” of adult Negro males,Am. J. Med. 18:428, 1955. 7. Greene, C. R., and Kelly, J. J., Jr.: Electrocardiograms of the healthy adult Negro, Circulation 20:906, 19.59. 8. Powell, S. J.: Unexplained electrocardiograms in the African, Brit. Heart J. 21:263, 19.59. 9. Thomas, J., Harris, E., and Lassiter, G.: Observations on the T wave and S-T segment changes in the precordial electrocardiogram of 320 young Negro adults, Am. J. Cardiol. 5:468, 1960. 10. Brink, A. J.: An investigation of factors influencing repolarization G the human heart, South African I. Clin. SC. 2:288. 1951. M. j.: Normal varian& in the elec11. Goldman, trocardiogram leading to cardiac invalidism, AM. HEART J. 59:71, 1960. E.: Unipolar lead electrocardiog12. Goldberger, raphy, ed. 3, London, 13. Wasserburger, R. H., Siebecker, K. L., Jr., and Lewis, W. C.: The effect of hyperventilation on the normal adult electrocardiogram, Circulation 13:850, 1956. 14. Suarez, R. M., and Suarez, Jr., Ii. M.: The T wave of the precordial electrocardiogram at different age levels, AM. HEART J. 32:480, 1946. 15. Magendantz, H., and Shortsleeve, J.: Electrocardiographic abnormalities in patients exhibiting anxiety, Aw. HEART J. 42:849, 1951. R., and Krause, M.: Changes of the 16. Mainzer, electrocardiogram brought about by fear, Cardiology 3:286, 1939. 17. Mainzer, F., and Krause, M.: The influence of fear on the electrocardiogram, Brit. Heart J. 2:221, 1940. S. A., Abhyankar, R. N., and Tdhir, 18. Rahman, A.: Effect of cooling the anterior chest wall on the T wave of the electrocardiogram, Au. HEART J. 47:394, 1954. I., and Edwards, W. L.: Misinterpre19. Rochlin, tation of electrocardiograms with post-prandidl ‘I’ wave inversion, Circulation 10:843, 1954. 20. Johnston, F. D., Ryan, J. M., and Bryant, J. M.: The electrocardiogram and the position of the heart, AM. HEART J. 43:306, 1952. 21. Grant, R. P., Estes, E. H., and Doyle, J. T.: Spatial vector electrocardiography; the clinical characteristics of the ST and T vectors, Circulation 3:182, 1951. 22. Dowling, C. V., and Hellerstein, J. K.: Factors influencing the T wave of the electrocardiogram. II. Effects of drinking iced water, AM. HEART J. 41~58, 1951. 23. Scherf, D., and Schlachman, M.: The electrocardiographic changes caused by hyperventilation, Am. J. M. SC. 213:342, 1947. 24. Wasserburger, R. H., and Lotenz, T. H.: The effect of hyperventilation and Pro-Banthine on isolated K--ST segment and T wave abnormalities. AM. HEART I. 51:666. 1956. 25. Wendkds, M. H., ani Logue, ‘R. B.: Unstable T waves in Leads II and III in persons with neurocirculatory asthenia, .4~. HEART J. 31:711, 1947. 26. Woodruff, L. W.: A clinical study of respiratory
312
27.
28.
29.
30.
31.
32.
33.
34.
3s.
36.
37.
38.
Blackman and Kuskin.
variations in the form of the electrocardiogram, AM. HEART J. 8:412, 1933. Leimdorfer, A.: The electrocardiographic response to changes of posture during respiratory arrest following deep inspiration or expiration; clinical significance, Ann. Int. Med. 29:1043, 1948. Norris, G. L., and Massie, E.: The effect of a single inspiration in Lead III and a precordial lead of the human electrocardiogram, Ann. Int. Med. 34:641, 1951. Bixby, E. W., Jr.: Simple technic using orthostatic and Valsalva maneuvers to prove the existence of the electrocardiographic unstable T wave. Abstracts of 628th Scientific Sessions of the American Heart Association. Circulation 14:911, 1956. Lewis, T.: The mechanism and graphic registration of the heart beat, ed. 3, London, 1925, Shaw and Sons. Wilson, F N. : The distribution of the potential differences produced by the heart beat within the body and at its surface, AM. HEART J. 5:599, 1930. Wilson, F. N., Johnston, F. D., Rosenbaum, F. F., Erlanger, H., Kossmann, C. E., Hecht, H. II.. Cotrim. Iv.. Menezes de Oliveira. R.. Scarsi,’ R., and Baiker, P. S.: The precdrdiai electrocardiogram, AM. HEART J. 27:19, 1944. Einthoven, W., Fahr, G., and dewaart, A.: On the direction and manifest size of the variations of potential in the human heart and the influence of the position of the heart on the form of the electrocardiogram, AM. HEART J. 40:163, 1950. Kuskin, L., and Brockman, L.: The direction of the precordial T waves in 321 normal infants and children. Am. I. M. SC. 218:65. 1949. BIu&nthal,’ M. j., and Blackman, N. S.: Normal respiratory variation of the T wave in Lead I of the electrocardiogram, New York J. Med. 50:335, 1950. Groedel, F. M., and Borchardt, P. R.: Direct electrocardiography of the human heart, New York, 1948, The Brooklyn Medical Press. Carouso, G. J., Chevalier, H. A., Latscha, I., and LenPgre, J.: Epicardial electrocardiograms recorded in the course of seven cases of heart surgery, Circulation 5:48, 1952. Jouve, A., Carriol, J., Velasque, P., Benyamine,
39.
40.
41. 42.
43.
44.
4.5.
46.
47.
48.
49.
50.
51.
R., and Peytavy, Ii.: Comparison of epicardial and precordial leads in man, Cardiologia 33:4.5, 19.58. Jouve, A., Henry, E., Carriol, J., Velasque, P., and Benyamine, R.: The epicardial leads in man, with report of one case with anatomic control, Arch. mal. coeur 51:626, 1958. Jouve, A., Carriol, J., Torresani, J., Benyamine, R., \relasque, R., and Peytavy, R.: Epicardial leads in man, AM. HEART J. 59:856, 1960. Miyaji, M.: The direct epicardial electrocardiogram. M. 1. Osaka Universitv 814:785. 19.58. garbato, E:, Pileggi, R., Debes, A. C., Fljioka, T., Magalhses, M. S., Tranchesi, J., San Juan, E., and D&court, L. V.: Study of the sequence of ventricular activation and the QRS complex of the normal human heart using direct epicardial leads, AM. HEART J. 55:867, 1958. Barbato, E., Debes, A. C., Fujioka, T., Pileggi, F., Zerbini, E. J., and D&court, L. V.: Direct epicardial and thoracic leads; their relationship in man, AM. HEART J. 58:238, 1959. Schwan, H. I’., and Kay, C. F.: Specilic resistance of body tissues, Circulation Res. 4:664, 1956. Schwan, H. I’., and Kay, C. F.: The conductivitv of living tissues. Ann. New York Acad. SC. f&1007, 1957. ’ Katz, L. N., Gutman, I., and Ocko, F. H.: Alterations in the electrical field produced by changes in the contacts of the heart with the bodv. Am. 1. Phvsiol. 116:302. 1936. I&&, H. *C., alid van Milaan, J. B.: Measurements of the specific resistance of the human body to direct current, acta med. scandinav. 114:584, 1943. D.: A Eycleshymer, A. C., and Schoemaker, cross-section anatomy, New York, 1911, D. Appelton-Century Co., Inc. Zdansky, E., and Boyd, L. J.: Roentgen diagnosis of the heart and great vessels, 1953, New York, Grune & Stratton, Inc. Dressler, W., and Roesler, H.: The significance of notched T waves. (Unpublished observations.) Spalteholz, &‘. : Hand-atlas of human anatomy, Philadelphia, J. B. Lippincott Company, Fig. 679, p. 587.
T wavm
in the precordial
eleckocardkqp-am
d norm-d
#es
Norman S. Blackman, M.D.* Lawrence Kuskin, M.D.** New York, N. Y.
S
harp19 inverted T waves in the precordial electrocardiogram have been reported in patients without evidence of clinical heart disease. Inversion of the T waves in Leads V, through Vq have been found so frequently in normal children that it. has been called “the normal juvenile pattern.” In addition, inversion of the T waves over isolated areas of the precordium, as in V, or Vq areas, have been reported in healthy adults. Inversions of the precordial T waves similar to both of the above-mentioned patterns have been reported in normal adult Negroes,leg as well as in Caucasians.*r3f9-11 Findings such as these in adults without heart disease have been a source of deep concern because the patterns are alarmingly similar to those often found with acute myocardial disease. No satisfactory explanations have been given for these observations. Some possibilities which have been suggested include: the influence of a relative deficiency of potassium,12~13 the effects of aging,14 anxiety,‘5 fear,16J’ cooling of the precordial region,lOrls influence of the intake of food,lg rotation of the heart in a clockwise position,20 impact of the cardiac From
apex against the chest wa11,21 local pericardial or myocardial disease,21 drinking of ice water,22 differences in myocardial hyperventilation,13J3s24 blood suPPlY,1o sympathetic - parasympathetic imbalance,10,26 posture, 2os27the effects of respiration,26-2g and the influence of local electrical potentials.30-33 We have studied the form34 and the effects of respiration on the T wave.35 Thus, we were interested in finding inverted precordial T waves in the electrocardiogram of a clinically normal adolescent boy. Because of these findings he was prohibited from athletic activities, although he was an outstanding athlete. However, when he took a deep breath and held it, the inverted T waves in V4 immediately became upright and normal in appearance. The sudden change from an apparently abnormal to a familiar, normal-appearing pattern suggested that the changes were not evidence of myocardial disease. Within a short period of time, 4 similar cases came to our attention. The following is a presentation of our findings. The factors which may be responsible for the dramatic changes in the ECG are discussed.
the Cardiac Consultation Service, Bureau for Handicapped Children. New York City Department of Health, New York. N. Y. Received for publication June 3, 1963. *Clinical Assistant Professor of Medicine, State University of New York Downstate Medical Center, Brooklyn, N. Y.; Cardiac Consultant, New York City Department of Health; Associate Attending Physician, The Brooklyn and The Beckman-Downtown Hospitals. Address: 100 Remaen St., Brooklyn 1, N. Y. **Clinical Assistant Professor of Environmental Medicine and Community Health, State University of New York Downstate Medical Center. Brooklyn, N. Y.; Chief, Cardiac Consultation Service, New York City Department of Health, Brooklyn; Attending Pediatrician and Chief of Pediatric Cardiology Clinic, Maimonides Hospital, Brooklyn, N. Y.
304
Vohme Number
67 3
Inverted
T waves in precordial
Findings The clinical features of our 5 cases, summarized in Table I, are within normal limits. Initially, all patients had been referred for evaluation of a systolic heart murmur which was found on a routine physical examination at school. Although equal numbers of males and females are seen at our clinic, all of our patients were males. Four were Negroes, two of whom were trained athletes. The electrocardiographic tracings (Figs. l-5) show seemingly abnormal inversion of the T waves in Va or Vq precordial leads, with “cove-planing” of the S-T segments in Cases 2, 3, 4, and 5. The lower tracings were continuously recorded (except in Fig. 4) to show the rapid changes in the tracing when the subject took a deep breath. With this maneuver the seemingly abnormal S-T segments and T waves quickly became normal in appearance. The QRS contour, however, was not significantly changed, except for some changes in the voltage. This would seem to indicate that the reversal in the direction of the T waves as a result of the inspiration is not secondary to alterations in the QRS complex
Table
Case
I. Summary
Age
of clinical
Race
Sex
Discussion
An electrode placed on the precordium is displaced anteriorly and superiorly by the movement of the chest wall on deep inspiration. At the same time the heart is displaced inferiorly as it follows the descent of the diaphragm. This results in a shift in the spatial relations between the precordial electrode and the local area of underlying epicardial surface. Jn addition, other changes occur which may be of profound significance. The anatomy of the left lung and reflexions of the pleura are such that an area overlying the anterior surface of the heart is known as “the cardiac notch.‘lS1 Here the anterior surface of the heart is covered by a minimum of lung tissue or none at all (see Figs. 6 and 7). This is normally under the precordial area between Vz and Vq electrode positions on the chest. In this region, therefore, the anterior surface of the heart is in closest approximation to the chest wall.** However, with deep inspiration there is ample room for aeration and expansion of the left lung anteriorly and medially to cover much of the anterior surface of the heart. This removes the heart from its close proximity to the chest wall.
features of 5 normal adolescentswith inverted precordial T waves
Past h&ory
Performance
(YY.)
1.
G.R.
305
ECG of normal adolescents
BP (mm.
Murmurs
Fluo~osco~y
Hd
18 Negro M No cardiac symptoms
Varsity basket- 100/60 Innocentapical Upperlimit of norball team systolic ma1in size; slight nence
promiof right
ventricle 2.
J.S.
16
Negro
M
Occasional
Normal
11.5/80
Innocent systolic
apical
Heart normal in size and shape
105/70
Innocent systolic
apical
Heart normal in size and shape
130/80
Innocent systolic left sternal border
Heart normal in size and shape
122/68 Innocent apical
Heart normal in
precordial distress
vague
3.
B.B.
14
White
M
No cardiac symptoms
Normal
4.
A.C.
15
Negro
M
No cardiac symptoms
Normal track
5.
F.D.
14
Negro
M
No cardiac symptoms
Normal
varsity team
systolic
size and shape
Fig. I. ECG tracing of a 11or1na1 1%year-old .\egro boy, bvith illvcrtcd ‘1‘ wa\ es in Lead V: and low-voltage ‘1‘ waves in Lead \‘;. The lower two tracings are rontinuous recordings which show the immediate effect of deep inspiration.
Fig. 2. ECG tracing of a normal 16-year-old Negro boy, showing diphasic T waves in Leads VP, V1, VS; inverted T waves in Lead VI, with “cove-planed” S-T segments. The lower tracing (taken at reduced standardization) shows Lead VS continuously recorded during normal respiration and after the taking of a deep inspiration.
1'ohm? Ntrmbrr
67 3
Inverted T wuves in
precordial
ECG of
normal
adolescents
Fig. 3. ECG tracing of a normal 14-year-old white boy, showing the effects a deep inspiration upon the contours of the S-T segments and the T waves Leads VZ and Va.
of in
Fig. 4. ECG tracing of a normal 15year-old Negro boy, showing the effects of a deep inspiration on the S-T segments and inverted T waves in Leads V? and VEr. (The lower tracing is not continuous because of wandering of the base line.)
307
.4m. Heart I. March, 1964
Fig. 5. Electrocardiographic tracing of a normal 14-year-old Negro boy. The continuously recorded lower tracings show the effect of a deep inspiration upon the contours of S-T segments and T waves in Leads \1’3 and V,.
When the chest is fluoroscoped in the lateral view, the heart usually can be observed to follow the descent of the dia-
Fig.
6. Note
the cardiac
notch.
(After
Spalteholz.5’)
phragm on deep inspiration. The retrosternal field becomes broader and lighter in appearance. In some cases the chest wall separates from the heart sufficiently for one to see between them.49 Obviously, this space must be occupied by aerated lung tissue interposed between the anterior epicardial surface and the posterior surface of the sternum. It is inaccurate to consider the body tissues as homogeneous electrical conductors. Muscle tissue is an excellent conductor, blood has a higher resistivity,*’ and fully aeruted lung tissue is a relatively poor conductor of electrical currents.45-47 The heart may be considered to be more or less surrounded by aerated lung tissue which tends to insulate the local electrical potentials on its surface from the chest electrodes. Inverted precordial T waves are sometimes recorded from normal hearts in VI through Vq on the surface of the chest. It is pertinent, therefore, to consider the nature of the underlying electrical potentials found on the anterior epicardial surface
Volume Number
67 3
Inverted
T waves in @cordial
of the normal human heart. These have been studied by Groedel,36 Carouso,37 J ouve,38-40 Miyaji,l’ and Barbato.42T43 Except for the last named, these authors were primarily interested in the characteristics of the QRS. Dissimilarities are observed in the T waves when direct epicardial leads are compared with precordial leads. Fig. 8 is a reproduction of Barbato’s tracings obtained directly from the epicardial surface of a normal 43-year-old white man. For comparison, the curves obtained from the surface of the anterior chest wall of the same patient are also illustrated. The direct epicardial leads show local areas of sharply inverted T waves scattered over much of the anterior surfa.ce oj’ the heart. These were not recorded by the electrodes placed upon the precordium in VZ through V4 positions. Negative T waves are closely adjacent to and intermingle with areas of positive T waves. In such closely adjacent areas of the exposed heart, T-wave negativity could hardly be due to local differences in surface temperature.
Fig. 7. Cross section of Appleton-Century-Crofts.)
of chest
and V leads.
(From
ECG of normal adolescents
309
It seems that the orderly progression of upright T waves usually recorded in normal adults on the surface of the chest does not accurately correspond to those found on the local epicardial surface just underneath the electrodes. Our adolescent patients may be presumed to have the anatomic structure of heart, lungs, and chest wall intermediate between that of a child and an adult. Two were trained athletes with welldeveloped musculature and the ability to maximally ventilate their lungs far beyond that of a young child or an untrained adult. When they took a deep inspiration, the anterior chest wall moved a substantial distance away from the anterior surface of the heart, carrying with it the precordial electrodes placed on its surface. At the same time, the heart was displaced inferiorly with the descent of the diaphragm. Aerated lung tissue, usually minimal or absent over the area of “the cardiac notch” during quiet respiration, became greatly expanded both anteriorly and medially.
Eycleshymer
and Shoemaker,48
by permission
3 10
Blackman
recordibl
Fig. R. Comparison normal 43-year-old
chest
and h-uskipi
leads
of epicardial and chest leads in a white man. (After Barbato.43)
This tissue, a relatively poor conductor, was then interposed between the anterior surface of the heart and the chest wall. This may have resulted in the distortion of inverted T waves normally present in local areas on the epicardial surface of the heart. In children, and in some adolescents, the precordial electrodes (Vt-V,) are in close proximity to the heart. Therefore, they act chiefly like electrodes placed directly on the surface of the heart (direct electrodes). On deep inspiration, however, these electrodes became electrically distant, due to insulation by the interposition of aerated lung tissue. As a result, the same electrode may be only slightly influenced by the local epicardial potentials, and thus acts chiefly like a distant electrode. This hypothesis could explain the sudden reversion of the inverted T waves (exagger-
3tecl intrinsic effect) to T \33ves that were upright and normal (csaggeratc4 extrinsic effect). The so-called juvenile T-wave pattern may also be due to the exaggerated effect of local negative T-wave potentials normally present in certain areas on the anterior epicardial surface. These negative potentials can be transmitted to the anterior chest surface because of their closeness to and lack of insulation from this surface in a child. With growth, the chest wall becomes thicker, and the lurqgs cover more thoroughly the anterior surface of the heart. These changes with growth tend to insulate the local negative epicardia1 T waves. The upright T waves usually found in normal adults in Vz-V, nlust, therefore, be a result of predominantly extrinsic electrical potentials. By taking a deep inspiration, our adolescent patients (intermediate between childhood and adulthood) may have acutely simulated some of the anatomic changes in the heart-lung relations that normally occur only with growth and maturity. “Isolated areas of precordial T-wave negativity” have been recorded in normal adults on occasion.21 Such observations cannot be esplained on the basis of the precordial electrodes acting solely as distant electrodes, nor by vectorial concepts. Esaggerated local electrical proximity effects on the chest electrode by the normally present negative T potentials sometimes present on the surface of the heart are a reasonable esplanation for these observations. Their occurrence in some adults may be a result of unusually thin chest walls and,,‘or underdevelopment of the lungs in such individuals. It is difficult to estimate the importance of the changes in the spatial relations between the heart, lungs, and the electrode on the chest wall as a result of a deep inspiration. That the effects on conduction are probably considerable is suggested by the fact that in 3 of the 5 subjects the QRS comples became decreased in voltage after the taking of a deep, held inspiration. Despite this, the pattern of the QRS was altered only slightly or not at all. This may indicate that the shift in the heart and the chest electrode relative to each other in space was not great. The lack of persistence
Volttme 67
Inverted 1’ waves in prccordial ECG of normal adolescents
Number 3
of the abnormally
appearing
S-T segments and the negative precordial T waves when the electrode was lifted from the proximity of the epicardial surface by the deep inspiratory effort is worthy of note. Summary
and
conclusions
We have presented 5 cases of normal adolescent boys who had abnormally appearing negative precordial T waves accompanied in some instances by “cove-planed” S-T segments. The findings are similar to those often associated with acute, severe myocardial disease. These deviations became quite normal in appearance when the subjects took a maximum, held inspiration. An attempt has been made to explain our findings on the basis of known anatomic relations between the heart, lungs, and chest wall, on knowledge of the electrical conduction properties of tissues, and on the nature of electrical potentials found directly on the anterior epicardial surface of the heart. In addition, these have been offered as possible explanations for other unexplained electrocardiographic observations (i.e., the “negative juvenile T-wave pattern” found frequently in normal children, and the “isolated areas of precordial T-wave negativity” found occasionally in normal adults). When negative precordial T waves are recorded from otherwise normal adolescents or adults, the importance of an esaggerated local proximity effect should be considered. The immediate reversion of these seemingly abnormal findings to normal by the simple expedient of taking a deep, held inspiration should be considered additional evidence of their benignity. REFERENCES 1. Ashman, R.: An electrocardiographic study of Caucasians and Negroes, Tri-State M.J. 13:2686,1941. 2. Littman, D.: Persistence of the juvenile pattern in precordial leads of healthy adult Negroes, AM. HEART J. 32:370, 1946. 3. Littman, D.: Abnormal electrocardiograms in the absence of demonstrable heart disease, Am. J. Med. 5:33?, 1948. 4. Keller, D. H., and Johnson, J. B.: The T wave of the unipolar precordial electrocardiogram in normal adult Negro subjects, AX HEART J. 44:494, 1952. 5. Grusin, M. B.: Peculiarities of the African’s electrocardiogram and the changes observed in serial studies, Circulation 9:860, 1954.
311
6. Wasserburger,R. H.: Observationson the “juvenile pattern” of adult Negro males,Am. J. Med. 18:428, 1955. 7. Greene, C. R., and Kelly, J. J., Jr.: Electrocardiograms of the healthy adult Negro, Circulation 20:906, 19.59. 8. Powell, S. J.: Unexplained electrocardiograms in the African, Brit. Heart J. 21:263, 19.59. 9. Thomas, J., Harris, E., and Lassiter, G.: Observations on the T wave and S-T segment changes in the precordial electrocardiogram of 320 young Negro adults, Am. J. Cardiol. 5:468, 1960. 10. Brink, A. J.: An investigation of factors influencing repolarization G the human heart, South African I. Clin. SC. 2:288. 1951. M. j.: Normal varian& in the elec11. Goldman, trocardiogram leading to cardiac invalidism, AM. HEART J. 59:71, 1960. E.: Unipolar lead electrocardiog12. Goldberger, raphy, ed. 3, London, 13. Wasserburger, R. H., Siebecker, K. L., Jr., and Lewis, W. C.: The effect of hyperventilation on the normal adult electrocardiogram, Circulation 13:850, 1956. 14. Suarez, R. M., and Suarez, Jr., Ii. M.: The T wave of the precordial electrocardiogram at different age levels, AM. HEART J. 32:480, 1946. 15. Magendantz, H., and Shortsleeve, J.: Electrocardiographic abnormalities in patients exhibiting anxiety, Aw. HEART J. 42:849, 1951. R., and Krause, M.: Changes of the 16. Mainzer, electrocardiogram brought about by fear, Cardiology 3:286, 1939. 17. Mainzer, F., and Krause, M.: The influence of fear on the electrocardiogram, Brit. Heart J. 2:221, 1940. S. A., Abhyankar, R. N., and Tdhir, 18. Rahman, A.: Effect of cooling the anterior chest wall on the T wave of the electrocardiogram, Au. HEART J. 47:394, 1954. I., and Edwards, W. L.: Misinterpre19. Rochlin, tation of electrocardiograms with post-prandidl ‘I’ wave inversion, Circulation 10:843, 1954. 20. Johnston, F. D., Ryan, J. M., and Bryant, J. M.: The electrocardiogram and the position of the heart, AM. HEART J. 43:306, 1952. 21. Grant, R. P., Estes, E. H., and Doyle, J. T.: Spatial vector electrocardiography; the clinical characteristics of the ST and T vectors, Circulation 3:182, 1951. 22. Dowling, C. V., and Hellerstein, J. K.: Factors influencing the T wave of the electrocardiogram. II. Effects of drinking iced water, AM. HEART J. 41~58, 1951. 23. Scherf, D., and Schlachman, M.: The electrocardiographic changes caused by hyperventilation, Am. J. M. SC. 213:342, 1947. 24. Wasserburger, R. H., and Lotenz, T. H.: The effect of hyperventilation and Pro-Banthine on isolated K--ST segment and T wave abnormalities. AM. HEART I. 51:666. 1956. 25. Wendkds, M. H., ani Logue, ‘R. B.: Unstable T waves in Leads II and III in persons with neurocirculatory asthenia, .4~. HEART J. 31:711, 1947. 26. Woodruff, L. W.: A clinical study of respiratory
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