- Email: [email protected]
T wave changes in mitral stenosis
T Wave Changes in Mitral Stenosis* DONALD MCCAUGHAN, M.D., ROBERT E. PRIMEAU, M.D., F.R.c.P.(c)~ West
I
Roxbury,
N ANALYSIS of scalar
electrocardiograms, the electrical events of repolarization are usually considered in terms of a mean T vector, and as a consequence the only alteration of the T wave that is regarded as significant is a change in the In a previous article’ orientation of that vector. we introduced the concept of considering the T wave as two vectors, an initial and a terminal. This adds two further factors to be considered in T wave analysis: The relation of these two vectors to each other on the plane, i.e., the direction of T loop rotation on the plane, and the angle between the vectors or T loop configuration. Figures 1 and 2 show such an analysis of the normal T loop and the effect of right ventricular overload on the horizontal plane. The present study was undertaken to compare the usefulness of T wave axis and direction of inscription in the precordial leads with the current criteria for diagnosis of right ventricular overIn many inload in men with mitral stenosis. stances the T wave is normally directed, but the direction of inscription is altered to clockwise. This results in upright T waves in leads Vz to VB with a diphasic T wave in lead Vr, showing initial negativity and terminal positivity. If this pattern is recognized as abnormal, right ventricular overload may be suspected more frequently.
and
DAVID LITTMAIVN, M.D.
Massachusetts
on the horizontal plane Frank vectorcardiogram, the direction of inscription being determined visually as the vectorcardiogram was displayed on an oscilloscope screen from a tape recorder. The patients were divided into three groups on the basis of pulmonary artery mean pressure, and the parameters of the electrocardiogram were compared with each group and the total group. Group 7 consisted of 20 patients with pulmonary artery mean pressure of less than 25 mm. Hg at rest; group 2, 36 patients with pulmonary artery mean pressure of 25 to 39; group 3, 33 patients with resting mean pulmonary artery pressures of 40 mm. Hg or greater. The mean age of all patients was 42, with a range of Only 10 patients were older than 50 23 to 67 years. years. Fifty-eight patients were in normal sinus rhythm and 31 in atria1 fibrillation. Autopsy confirmation of the diagnosis was available in 18 cases. RESULTS Table I shows the major findings in the electrocardiograms for all parameters considered indicative of right ventricular overload. The percentage of positive results increased with increasing levels of pulmonary artery mean pressure, as expected.6s7 However, if group 3 is considered separately, the greatest incidence of positive results for any parameter was 60 per cent. Table II shows the direction of inscription of the horizontal plane T loop, determined from the V leads; “indeterminate” includes cases in which the direction of inscription was not obvious by inspection, either due to coarse atria1 fibrillation or to absence of a diphasic T complex in any lead. The percentage of clockwise T waves is a function of increasing pulmonary artery mean pressure, with 94 per cent clockwise in the group with pulmonary artery mean pressure greater than 40 mm. Hg. Figure 3 shows the T axis on the horizontal plane for the three groups.
PATIENTS AND METHODS All subjects with isolated mitral stenosis, proved by left and right heart catheterization and angiocardiography, were selected from our files. A total of 89 patients with adequate documentation of isolated mitral stenosis whose electrocardiograms showed a QRS duration of less than 0.12 sec. was available for analysis. The standard electrocardiograms were studied independently by each of the authors and all parameters usually considered diagnostic or suggestive of right ventricular overload were tabulated.2-6 In addition, the direction of inscription of the T loop in the horizontal plane was determined from the precordial leads. This was subsequently confirmed
DISCUSSION The
electrocardiographic
ventricular
overload
in
diagnosis adults
* From the Cardiology Section, Veterans Administration Hospital, West Roxbury, Mass. t Research Fellow. Work done during the tenure of a Research Fellowship from the Canadian 666
with Heart
THE AMERICANJOURNAL
of right acquired
Foundation.
OF CARDIOLOGY
T Wave
Changes
in Mitral
Stenosis
667
TABLE 1 Electrocardiographic Criteria of Right Ventricular Overload in the Three Groups of Patients with Mitral Stenosis Group 1 Criteria
FIG. 1. Normal T loop variations in the horizontal plane. A, the entire T loop lies on the negative side of derivation of lead Vi, thus resulting in a negative T wave. B, the mean T axis is at right angles to lead VI; the initial T vector lies on the positive side of derivation, and the terminal T vector lies on the negative side of derivation. The T wave in lead Vi is biphasic with an initial positive component. M = mean T vector; 1 = initial T vector; 2 = terminal T vector.
No.
RAD 110’ 0 RV, 7 mm. 3 R aVR 5 mm. 0 R/S V, = 1; RV, 2 7 mm. 1 S-T dcpresian, T inversion VI & RV, 5 mm. or mOre 0 RV, + SVsor vs 10.5 mm. or Vn jJ R/SVs >l QR in VI sv.
m,.
70
Group 2 No. 4;
Group 3 No.
All C.ura No. “;
“;,
0
2
5
6
IX
15 00
4
11 0
15 3
45 ‘J
22 3
24 3
5
3
8
8
24
I-’
13
0
2
5
16
48
IX
21
1
5
5
14
20
60
26
29
1 0 0
5 0 0
3 0 0
8 0 0
13 7 5
39 21 15
17 7 5
19 8 6
Pulmonary artery mean pressures: 25-39 mm.; Group 3,40+ mm.
TABLE
Group
1, <25
R
mm.;
9
Group 2,
II
Frequency of T Wave Inscription on the Horizontal Plane as Determined from the V Leads in the Three Groups of Patients
Group 1 2 3 Total FIG. 2. The horizontal plane T loop zn right ventricular overload. The mean T axis is normally directed, but the inscription is now clockwise. The initial and terminal T vectors are transposed, thus resulting in a biphasic T wave in lead Vi with an initial negative component.
heart disease is notoriously difficult.* In mitral stenosis most reports indicate that the electrocardiogram shows evidence of right ventricular overload in about 60 per cent of all cases.g-13 This is due to the fact that the QRS changes of right ventricular hypertrophy in the adult represent superimposition of increased right ventricular forces on a predominant levocardiogram. Diminution in the magnitude of the spatial QRS and a verticalization of the mid and terminal QRS forces results. The only change that may be seen in the scalar electrocardiogram is a vertical axis on the frontal plane and small complexes in V1 with an R/S ratio approaching one. The R wave in the right precordial leads later increases in size as the mid QRS force deviates anteriorly to the E point.14 This usually only occurs if the pulmonary artery mean pressure is VOLUME 20,
NOVEMBER
1967
Clockwise
Counterclockwise
No.
%
No.
%
7 15 31 53
35 42 94 60
8 14 0 22
40 39 0 25
Indeterminate No. %;, 5 7 2 14
25 19 6 15
greater than 40 mm. Hg at rest and the total pulmonary resistance is greater than 1,000 dynes sec. cmP5. In contrast to the QRS changes in right ven-
0
180’
Frc. 3. Horizontal plane T axis for the three groups of patients with mitral stenosis. The shaded areas indicate range, and the figures indicate mean T axis of each group.
McCaughan,
668
Primeau and Littmann
to Ve) in early right ventricular that is apparent is an ablead VI, indicating a clockdiagrammaticaiiy.
FIG. 5. Precordtal V leads (VI to Vs) in more severe right ventricular overload. Lead VI shows an inverted T wave. The diphasic-isoelectric T wave occurs in lead VP with an initial negative component. The T loop is shown diagrammatically.
tricular overload, the T wave changes appear with relatively mild degrees of right ventricular hypertrophy. The horizontal plane T wave becomes clockwise, a change that is usually evident in the precordial leads. This may occur Debefore the T wave axis deviates posteriorly. termination of T wave inscription on this plane is usually easy and provides valuable information. The alteration in the T wave may be stated as follows : T waves that are diphasic in lead V, with an initial negative and terminal positive component with upright T waves in the other precordial leads indicate right ventricular overload (Fig. 4). A similar pattern in lead VZ with a negative T wave in lead V, and upright T waves in other V leads represents a greater degree of right ventricular overload (Fig. 5). With increasing degrees of right ventricular overload this pattern shifts leftward across the chest Rarely, leads as the T axis deviates posteriorly. the T axis is such that the T wave is upright in all the V leads, VI to Vg, and is abnormally diphasic in V&.
inversion of the T wave in lead V1. If this configuration is recognized as a criterion of right ventricular overload, milder degrees of right ventricular overload are recognized before other alterations occur in the electrocardiogram. The present study indicates that it is a sensitive index of right ventricular overload. Furthermore, this configuration of the T wave does not occur in anterior myocardial infarction, the other most frequent cause of inversion of the T wave in the right precordial V leads.
FIG. 4. Precordial V leads (VI overload. The only change normal diphasic T wave in wise T ioop, which is shown
SUMMARY
In right ventricular overload, the horizontal plane T axis deviates posteriorly, and the direcThe retion of inscription alters to clockwise. sult of this change in inscription is an alteration in the configuration of the T wave in the right precordial leads. Initially, lead V1 shows a diphasic T wave with initial negativity and terminal positivity. With increasing degrees of right ventricular overload, the T wave becomes inverted in lead V1, and this abnormal diphasic configuration shifts to lead Vz and later to lead Vt or Vq. Alteration of the configuration of the T wave in lead V1 frequently occurs before the T axis has deviated sufficiently posteriorly to cause
REFERENCES 1. MCCAUGHAN,D., PRIMEAU,R. E. and LITTMANN,D. The precordial T wave. .4m. J. Cardiol., 20: 660, 1967. 2. SOKOI-OW, M. and LYON, T. P. The ventricular complex in right ventricular hypertrophy as obtained by unipolar precordial and limb leads. Am. Heart J., 38: 273, 1949. 3. MILNOR, W. R. Electrocardiogram and vectorcardiogram in right ventricular hypertrophy and ;$tt~. bundle branch block. Circulation, 16: 348, 4. SCOTT, R. C. The correlation between the electrocardiographic patterns of ventricular hypertrophy and the anatomic findings. Circulation, 21: 256,196O. 5. ROMAN, G. T., WALSH, T. J. and MASSIE, E. Right ventricular hypertrophy. Am. J. Cardiol., 7: 481, 1961. 6. WHITAKER, W. Clinicai diagnosis of pulmonary hypertension in patients with mitral stenosis. Quart. J. Med., 23: 105, 1954. 7. SEMLER, H. J. and PRUITT, R. D. An electrocardiographic estimation of the pulmonary vascular obstruction in 80 patients with mitral stenosis. Am. Heart J., 59: 541, 1960. 8. GOODWIN,J. F. and ABKIN, 2. H. The cardiogram of congenital and acquired right ventricular hypertrophy. Brit. Heart J., 21: 523, 1959. 9. TROUNCE, J. R. The electrocardiogram in mitral stenosis. Brit. Heart J., 14: 185, 1952. 10. SCOTT, R. C., KAPLAN, S., FOWLER, N. 0. and THE AMERICANJOURNAL OF CARDIOLOGY
‘1’ Wave
Changes
\\ .I. ‘l‘he t-lectrocardiographic pattern of right vrntricular hypertrophy in mitral valw disease. Cirruldon, 11 : 761, 1955. Il. MORRIS, ‘I’. I,. and WHITAKER, W. The ventricular patterns in the right precordial leads in mitral stenosis. Am. Heart J., 52: 738, 1956. 12. GRAF, W. S., GUNTHER, L. and ALLENSTEIN, B. QRS pattern in mitral stenosis. Am. J. Cardiol., 14: 266, 1964. SI.II.ES,
VOLUME
20. NOVEMBER
1967
in Mitral
Stenosis
069
13. LEE, YLJ-CHUEN, S(:HERLIS, L. ;~nti SINGL.ET~N, R. ‘1‘. Mitral stenosis. .Im. Hart ./.. 69: 559, 1965. 14. MCCAUGIIAN, D., KOROXENIDIS, G. T., HOPPI:, L. G. and WILLIAMS, C. New vectorcardiographic criteria for the diagnosis of acquired right ventricular hypertrophy: Comparison with standard electrocardiographic criteria (i\bstr.). Circulation, 28: 766, 1963.
I
Roxbury,
N ANALYSIS of scalar
electrocardiograms, the electrical events of repolarization are usually considered in terms of a mean T vector, and as a consequence the only alteration of the T wave that is regarded as significant is a change in the In a previous article’ orientation of that vector. we introduced the concept of considering the T wave as two vectors, an initial and a terminal. This adds two further factors to be considered in T wave analysis: The relation of these two vectors to each other on the plane, i.e., the direction of T loop rotation on the plane, and the angle between the vectors or T loop configuration. Figures 1 and 2 show such an analysis of the normal T loop and the effect of right ventricular overload on the horizontal plane. The present study was undertaken to compare the usefulness of T wave axis and direction of inscription in the precordial leads with the current criteria for diagnosis of right ventricular overIn many inload in men with mitral stenosis. stances the T wave is normally directed, but the direction of inscription is altered to clockwise. This results in upright T waves in leads Vz to VB with a diphasic T wave in lead Vr, showing initial negativity and terminal positivity. If this pattern is recognized as abnormal, right ventricular overload may be suspected more frequently.
and
DAVID LITTMAIVN, M.D.
Massachusetts
on the horizontal plane Frank vectorcardiogram, the direction of inscription being determined visually as the vectorcardiogram was displayed on an oscilloscope screen from a tape recorder. The patients were divided into three groups on the basis of pulmonary artery mean pressure, and the parameters of the electrocardiogram were compared with each group and the total group. Group 7 consisted of 20 patients with pulmonary artery mean pressure of less than 25 mm. Hg at rest; group 2, 36 patients with pulmonary artery mean pressure of 25 to 39; group 3, 33 patients with resting mean pulmonary artery pressures of 40 mm. Hg or greater. The mean age of all patients was 42, with a range of Only 10 patients were older than 50 23 to 67 years. years. Fifty-eight patients were in normal sinus rhythm and 31 in atria1 fibrillation. Autopsy confirmation of the diagnosis was available in 18 cases. RESULTS Table I shows the major findings in the electrocardiograms for all parameters considered indicative of right ventricular overload. The percentage of positive results increased with increasing levels of pulmonary artery mean pressure, as expected.6s7 However, if group 3 is considered separately, the greatest incidence of positive results for any parameter was 60 per cent. Table II shows the direction of inscription of the horizontal plane T loop, determined from the V leads; “indeterminate” includes cases in which the direction of inscription was not obvious by inspection, either due to coarse atria1 fibrillation or to absence of a diphasic T complex in any lead. The percentage of clockwise T waves is a function of increasing pulmonary artery mean pressure, with 94 per cent clockwise in the group with pulmonary artery mean pressure greater than 40 mm. Hg. Figure 3 shows the T axis on the horizontal plane for the three groups.
PATIENTS AND METHODS All subjects with isolated mitral stenosis, proved by left and right heart catheterization and angiocardiography, were selected from our files. A total of 89 patients with adequate documentation of isolated mitral stenosis whose electrocardiograms showed a QRS duration of less than 0.12 sec. was available for analysis. The standard electrocardiograms were studied independently by each of the authors and all parameters usually considered diagnostic or suggestive of right ventricular overload were tabulated.2-6 In addition, the direction of inscription of the T loop in the horizontal plane was determined from the precordial leads. This was subsequently confirmed
DISCUSSION The
electrocardiographic
ventricular
overload
in
diagnosis adults
* From the Cardiology Section, Veterans Administration Hospital, West Roxbury, Mass. t Research Fellow. Work done during the tenure of a Research Fellowship from the Canadian 666
with Heart
THE AMERICANJOURNAL
of right acquired
Foundation.
OF CARDIOLOGY
T Wave
Changes
in Mitral
Stenosis
667
TABLE 1 Electrocardiographic Criteria of Right Ventricular Overload in the Three Groups of Patients with Mitral Stenosis Group 1 Criteria
FIG. 1. Normal T loop variations in the horizontal plane. A, the entire T loop lies on the negative side of derivation of lead Vi, thus resulting in a negative T wave. B, the mean T axis is at right angles to lead VI; the initial T vector lies on the positive side of derivation, and the terminal T vector lies on the negative side of derivation. The T wave in lead Vi is biphasic with an initial positive component. M = mean T vector; 1 = initial T vector; 2 = terminal T vector.
No.
RAD 110’ 0 RV, 7 mm. 3 R aVR 5 mm. 0 R/S V, = 1; RV, 2 7 mm. 1 S-T dcpresian, T inversion VI & RV, 5 mm. or mOre 0 RV, + SVsor vs 10.5 mm. or Vn jJ R/SVs >l QR in VI sv.
m,.
70
Group 2 No. 4;
Group 3 No.
All C.ura No. “;
“;,
0
2
5
6
IX
15 00
4
11 0
15 3
45 ‘J
22 3
24 3
5
3
8
8
24
I-’
13
0
2
5
16
48
IX
21
1
5
5
14
20
60
26
29
1 0 0
5 0 0
3 0 0
8 0 0
13 7 5
39 21 15
17 7 5
19 8 6
Pulmonary artery mean pressures: 25-39 mm.; Group 3,40+ mm.
TABLE
Group
1, <25
R
mm.;
9
Group 2,
II
Frequency of T Wave Inscription on the Horizontal Plane as Determined from the V Leads in the Three Groups of Patients
Group 1 2 3 Total FIG. 2. The horizontal plane T loop zn right ventricular overload. The mean T axis is normally directed, but the inscription is now clockwise. The initial and terminal T vectors are transposed, thus resulting in a biphasic T wave in lead Vi with an initial negative component.
heart disease is notoriously difficult.* In mitral stenosis most reports indicate that the electrocardiogram shows evidence of right ventricular overload in about 60 per cent of all cases.g-13 This is due to the fact that the QRS changes of right ventricular hypertrophy in the adult represent superimposition of increased right ventricular forces on a predominant levocardiogram. Diminution in the magnitude of the spatial QRS and a verticalization of the mid and terminal QRS forces results. The only change that may be seen in the scalar electrocardiogram is a vertical axis on the frontal plane and small complexes in V1 with an R/S ratio approaching one. The R wave in the right precordial leads later increases in size as the mid QRS force deviates anteriorly to the E point.14 This usually only occurs if the pulmonary artery mean pressure is VOLUME 20,
NOVEMBER
1967
Clockwise
Counterclockwise
No.
%
No.
%
7 15 31 53
35 42 94 60
8 14 0 22
40 39 0 25
Indeterminate No. %;, 5 7 2 14
25 19 6 15
greater than 40 mm. Hg at rest and the total pulmonary resistance is greater than 1,000 dynes sec. cmP5. In contrast to the QRS changes in right ven-
0
180’
Frc. 3. Horizontal plane T axis for the three groups of patients with mitral stenosis. The shaded areas indicate range, and the figures indicate mean T axis of each group.
McCaughan,
668
Primeau and Littmann
to Ve) in early right ventricular that is apparent is an ablead VI, indicating a clockdiagrammaticaiiy.
FIG. 5. Precordtal V leads (VI to Vs) in more severe right ventricular overload. Lead VI shows an inverted T wave. The diphasic-isoelectric T wave occurs in lead VP with an initial negative component. The T loop is shown diagrammatically.
tricular overload, the T wave changes appear with relatively mild degrees of right ventricular hypertrophy. The horizontal plane T wave becomes clockwise, a change that is usually evident in the precordial leads. This may occur Debefore the T wave axis deviates posteriorly. termination of T wave inscription on this plane is usually easy and provides valuable information. The alteration in the T wave may be stated as follows : T waves that are diphasic in lead V, with an initial negative and terminal positive component with upright T waves in the other precordial leads indicate right ventricular overload (Fig. 4). A similar pattern in lead VZ with a negative T wave in lead V, and upright T waves in other V leads represents a greater degree of right ventricular overload (Fig. 5). With increasing degrees of right ventricular overload this pattern shifts leftward across the chest Rarely, leads as the T axis deviates posteriorly. the T axis is such that the T wave is upright in all the V leads, VI to Vg, and is abnormally diphasic in V&.
inversion of the T wave in lead V1. If this configuration is recognized as a criterion of right ventricular overload, milder degrees of right ventricular overload are recognized before other alterations occur in the electrocardiogram. The present study indicates that it is a sensitive index of right ventricular overload. Furthermore, this configuration of the T wave does not occur in anterior myocardial infarction, the other most frequent cause of inversion of the T wave in the right precordial V leads.
FIG. 4. Precordial V leads (VI overload. The only change normal diphasic T wave in wise T ioop, which is shown
SUMMARY
In right ventricular overload, the horizontal plane T axis deviates posteriorly, and the direcThe retion of inscription alters to clockwise. sult of this change in inscription is an alteration in the configuration of the T wave in the right precordial leads. Initially, lead V1 shows a diphasic T wave with initial negativity and terminal positivity. With increasing degrees of right ventricular overload, the T wave becomes inverted in lead V1, and this abnormal diphasic configuration shifts to lead Vz and later to lead Vt or Vq. Alteration of the configuration of the T wave in lead V1 frequently occurs before the T axis has deviated sufficiently posteriorly to cause
REFERENCES 1. MCCAUGHAN,D., PRIMEAU,R. E. and LITTMANN,D. The precordial T wave. .4m. J. Cardiol., 20: 660, 1967. 2. SOKOI-OW, M. and LYON, T. P. The ventricular complex in right ventricular hypertrophy as obtained by unipolar precordial and limb leads. Am. Heart J., 38: 273, 1949. 3. MILNOR, W. R. Electrocardiogram and vectorcardiogram in right ventricular hypertrophy and ;$tt~. bundle branch block. Circulation, 16: 348, 4. SCOTT, R. C. The correlation between the electrocardiographic patterns of ventricular hypertrophy and the anatomic findings. Circulation, 21: 256,196O. 5. ROMAN, G. T., WALSH, T. J. and MASSIE, E. Right ventricular hypertrophy. Am. J. Cardiol., 7: 481, 1961. 6. WHITAKER, W. Clinicai diagnosis of pulmonary hypertension in patients with mitral stenosis. Quart. J. Med., 23: 105, 1954. 7. SEMLER, H. J. and PRUITT, R. D. An electrocardiographic estimation of the pulmonary vascular obstruction in 80 patients with mitral stenosis. Am. Heart J., 59: 541, 1960. 8. GOODWIN,J. F. and ABKIN, 2. H. The cardiogram of congenital and acquired right ventricular hypertrophy. Brit. Heart J., 21: 523, 1959. 9. TROUNCE, J. R. The electrocardiogram in mitral stenosis. Brit. Heart J., 14: 185, 1952. 10. SCOTT, R. C., KAPLAN, S., FOWLER, N. 0. and THE AMERICANJOURNAL OF CARDIOLOGY
‘1’ Wave
Changes
\\ .I. ‘l‘he t-lectrocardiographic pattern of right vrntricular hypertrophy in mitral valw disease. Cirruldon, 11 : 761, 1955. Il. MORRIS, ‘I’. I,. and WHITAKER, W. The ventricular patterns in the right precordial leads in mitral stenosis. Am. Heart J., 52: 738, 1956. 12. GRAF, W. S., GUNTHER, L. and ALLENSTEIN, B. QRS pattern in mitral stenosis. Am. J. Cardiol., 14: 266, 1964. SI.II.ES,
VOLUME
20. NOVEMBER
1967
in Mitral
Stenosis
069
13. LEE, YLJ-CHUEN, S(:HERLIS, L. ;~nti SINGL.ET~N, R. ‘1‘. Mitral stenosis. .Im. Hart ./.. 69: 559, 1965. 14. MCCAUGIIAN, D., KOROXENIDIS, G. T., HOPPI:, L. G. and WILLIAMS, C. New vectorcardiographic criteria for the diagnosis of acquired right ventricular hypertrophy: Comparison with standard electrocardiographic criteria (i\bstr.). Circulation, 28: 766, 1963.