The vectorcardiogram in prolapsed mitral leaflet myocardopathy

J. ELECTROCARDIOLOGY, 7 (1) 37-42, 1974

The Vectorcardiogram in Prolapsed Mitral Leaflet Myocardopathy BY SE DO CHA, M.D.,* ALDEN S. GOOCH, M.D.,t SING SAN YANG, M.D.,** AND HARRY GOLDBERG, M . D . t t

SUMMARY

S u p r a v e n t r i c u l a r or v e n t r i c u l a r a r r h y t h m i a s , a t r e s t or p r o v o k e d b y exercise, a r e c o m m o n findings. 7'1~ T h e m o s t f r e q u e n t l y r e p o r t e d E C G c h a n g e h a s b e e n in t h e T w a v e s ; b u t its c a u s e h a s not b e e n e l u c i d a t e d a n d a d e t a i l e d d e s c r i p t i o n in a l a r g e series of p a t i e n t s h a s not b e e n p r e s e n t e d . T h i s is a n a n a l y s i s of 87 p r o v e n c a s e s of p r o l a p s e d m i t r a l leaflet (PML) m y o c a r d o p a t h y w i t h a n a n a l y s i s of QRS a n d T c h a n g e s as recorded b y v e c t o r c a r d i o g r a p h y .

The vectorcardiograms (VCG) of 87 cases of prolapsed mitral leaflets syndrome were analyzed with reference to clinical, electrocardiographic and catheterization data. A total of 36.8% of electrocardiograms and 72.4% o f v e c t o r c a r d i o g r a m s displayed abnormal T changes. T loop changes included abnormal T vector directions, wide QRS-T angles and increased T vector magnitudes. Abnormal QRS loops were seen in 30 (34.5%) VCG. All thirty-two patients with chest pain had normal selective coronary arteriograms. It is believed, therefore, that these primary T vector abnormalities are not ischemic and that they are related to some myocardial changes of unknown etiology.

MATERIALS AND METHODS The patients included 20 males and 67 females. Their ages ranged from 15 to 68 years, with the mean age of 43.8 years. Patient selection was based on cardiac catheterization findings. All had systolic prolapse of the mitral valve leaflets as demonstrated by left ventriculography. Several had prolapse of the tricuspid valve in addition. The patients with other cardiac abnormalities were excluded from this study. All patients had 12-lead scalar electrocardiograms and treadmill exercise tests as well as vectorcardiograms (VCG). VCG were recorded with the F r a n k lead system on a vectorcardiograph (Hewlett-Packard system-1507 A). QRS loops were analyzed for rotation, size, and deformities. T loops were amplified to 0.5 mv/cm. The following measurements were made from each plane: maximal QRS vector direction, maximal T vector direction, m a g n i t u d e of the m a x i m a l T vector and length/width ratio of the T loop. The p a t i e n t s were divided into two groups according to their ages: group A, 39 yrs old or less, and group B, 40 yrs or more. The measurements in each group were compared with those in the respective groups of the n o r m a l VCG d a t a of Silverberg. 13 His findings were similar to the VCG data of other groups. 14-17 All patients had combined right and left heart catheterization. There were no a b n o r m a l i t i e s of pressures or cardiac outputs. ~ Left ventriculograms were obtained in the RAO projection recorded on 35mm Shellburst Film at 60 frames/sec. They were analyzed for the presence and magnitude of regional asynergy. The severity of these changes was correlated with the presence of T loop abnormalities and QRS-T angles. Selective coronary angiography by Sone's or Judkin's technique were performed in 32 patients who had chest pain.

T h e condition r e c o g n i z e d b y systolic clicks and/or systolic m u r m u r s h a s b e e n identified w i t h " p r o l a p s i n g " , "flopping", or " b a l l o o n i n g " of t h e m i t r a l l e a f l e t s 1-5 In addition, t h e r i g h t h e a r t m a y be i n v o l v e d w i t h p r o l a p s e of t h e t r i c u s p i d leaflets. 6 T h e i n v o l v e m e n t is not o n l y in t h e v a l v e leaflets b u t also in t h e m y o c a r d i u m . 7~ W h e t h e r t h e r e is a c a u s e a n d result relationship between the myocardial changes and valve prolapse and other manif e s t a t i o n s , s u c h as a r r h y t h m i a s a n d c h e s t pains, r e m a i n s u n k n o w n . T h e e l e c t r o c a r d i o g r a p h i c c h a n g e s assoc i a t e d w i t h t h i s condition a r e v a r i e d a n d m a y include p r o l o n g e d Q-T i n t e r v a l s , U w a v e s a n d o c c a s i o n a l l y Q R S i n f a r c t i o n p a t t e r n s . 3's

*Fellow in Cardiology, Deborah Heart and Lung Center tAssoc. Cardiologist, Deborah H e a r t and Lung Center and Assoc. Clinical Prof. of Medicine, Temple University **Assoc. Cardiologist and Director of Electrocardiology, Deborah Heart and Lung Center, Clinical Assistant Prof. of Medicine, Temple University t t C h i e f of Cardiology, Deborah Heart and Lung Center and Chief of Cardiology, Albert Einstein Medical Center, Prof. of Medicine, Temple University Reprint requests to: Alden S. Gooch, M.D., Deborah Heart and Lung Center, Browns Mills, N.J. 08015

RESULTS Electrocardiographic findings ((Table

1) 26 of 87 p a t i e n t s (29.9%) showed a b n o r m a l T w a v e c h a n g e s ; T w a v e i n v e r s i o n s in leads II,

37

38

C H A ET A L

III and AVF being the most frequent findings, comprising 25.3%. Other changes noted include: T inversions in the precordial leads (4 cases), complete left bundle branch block (1 case), posterior myocardial infarction (1 case),

incomplete right bundle branch block (1 case), and left axis deviation o f - 3 0 ~ or more (3 cases). The maximal QRS vector direction and inscription (Table 2)

TABLE 1 Electrocardiographic Findings - 87 Patients With Prolapsed Mitral Leaflets

TABLE 2 Vectorcardiographic QRS Loop Changes

55

Normal

32

Abnormal

T inversion in II, III, AVF*

Normal

57

Abnormal

30

Prominent anterior force (50% QRS loop area)

22

T inversion V 1 - V4

3

T inversion V 1 - V 6

1

Left axis deviation

(-30 ~ or more)

3

Incomplete RBBB

1

LBBB

1

Posterior myocardial infarction

1

11

Incomplete RBBB

5

Complete LBBB

1

Left axis deviation

(-35 ~ -37 ~ -50 ~

*Nine patients also had T inversion in V 5 - V 6 or V 1 - V 3

3

Left ventricular hypertrophy with strain

3

Right ventricular hypertrophy (type C)

2

Myocardial infarction (anterior; 1, lateral; 2, inferior; 2)

5

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Fig. 1. Maximal T vector directions in frontal plane. J. ELECTROCARDIOLOGY, VOL. 7, NO. 1, 1974

VCG IN PML MYOCARDOPATHY

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Fig. 2. Maximal T vector direction in left sagittal plane. T h i r t y patients had abnormal QRS loop changes. The maximal QRS vector was directed to the normal range in each plane in all except three patients with left axis deviation. Sixteen patients had QRS loop patterns compatible with a diagnosis of myocardial infarction, of which eleven had prominent anterior forces suggesting straight posterior infarction. O t h e r c h a n g e s included i n c o m p l e t e RBBB (5 cases), complete LBBB (1 case). Only 8 of these 30 patients had abnormal T vector changes which could be interpreted as secondary changes.

Maximal T vector direction (Figs. 1,2,3) Abnormal T vector directions were most frequently displayed in the transverse (horizontal) plane and included 37 cases (41.6%). The T vector was abnormally directed in 25 (29.4%) in the frontal plane and in 18 (21.2%) in the left sagittal plane (Table 3). QRS-T angle In the transverse plane, the QRS-T angle was abnormal in 27 patients (33.3%). In group A, 18 patients had narrow angles (4~ to 24 ~ and 6 patients had wide angles (77 ~ 80 ~ 100 ~ 101 ~ 103 ~ and 143~ In group B all 3 patients had a QRS-T angle exceeding 140 ~ (mean 173~ In the frontal plane, the QRS-T angle was abnormally wide in 25.3% - - mean 82.1 ~ in group A and 110.1 ~ in group B. In the left J. ELECTROCARDIOLOGY, VOL. 7, NO. 1, 1974

sagittal plane, the QRS-T angle was abnormal in 8 patients (11%). T vector magnitude Large numbers of patients had an increased m a g n i t u d e of t h e T vector: 45.2% in t h e transverse plane, 45.8% in the frontal plane and 55% in the left sagittal plane. These c h a n g e s were e q u a l l y d i s t r i b u t e d a m o n g those of group A and B. Length~width ratio of the T loop The length/width ratio of the T loop was normal (more than 2.6) in all but 3 instances, the average ratio being 6.4. The configurations of T loop were generally long and thin. Chest pains, ECG, VCG findings Fifty-one patients had atypical chest pains. Of these, 27 (52.9%) had abnormal ECGs, ST and T changes, while 32 patients (62.7%) had abnormal VCG T loops. Treadmill exercise did not induce ischemic ST-T changes in any of these subjects. Criteria for myocardial infarction was evident in the VCG of 5 patients whose coronary arteriograms were normal. Left v e n t r i c u l a r a s y n e r g y w a s demonstrated by ventriculography in 69 patients, 79.3%. There was no correlation between the magnitude of T vector changes and the presence of asynergy. The asynergy was seen as s e g m e n t a l d i s t o r t i o n s of c o n t r a c t i o n or relaxation, most often showing an anterior bulge combined with an inferior indentation.

40

C H A ET AL

DISCUSSION Abnormal T vector directions with normal maximal QRS vector directions may be defined as primary T abnormalities such as seen in m y o c a r d i a l ischemia, is digitalis effect, metabolic disorders or in myocardiopathies. 19 None of the patients of this study were receiving quinidine or digitalis t h e r a p y and none had a metabolic disorder. Castellanos et al 2~ reported that the direction ofT-loop is frequently abnormal (16 of 38 patients) and QRS-T angle is divergent (14 of 38 patients) in patients with old myocardial infarctions, and suggested this pattern could be due to a repolarization defect. In coronary heart disease, Abdulla and co-workers 21 reported that 50% of T vectors with abnormal direction are associated with QRS-T angles and low length/width ratios. Chou a n d co-workers 22 found a low length/width ratio of less than 2.6 in patients with myocardial infarction and postulated that this resulted from either a change in the sequence of re-

polarization or the decreased contribution from the necrotic area. The experiments of Burgess 23'2a showed an increase of the length/width ratio of the T loop when multiple repolarization boundaries coexist due to inhomogeneity of action potential durations. It is possible that the T-loop abnormalities in PML myocardopathy may represent such changes. The most significant findings of this study are: 1) normal inscriptions and maximal QRS vector directions and "infarction" patterns, 2) abnormal QRS-T angles, 3) increased T vector magnitudes, 4) abnormal T vector directions, 5) normal length/width ratio ofT loops, and 6) a greater degree of sensitivity of the VCG, as compared to ECG, in detecting these changes. The association of QRS and T wave abnormalities with PML myocardopathy has led to the assumptions of some investigators that the chest pains are truly ischemic in nature. T-wave inversions are most frequently found in leads II, III, AVF and V5-6 b u t coronary arteriographic findings have not been consis-

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Range Range

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Fig. 3. Maximal T vector direction in horizontal plane. J. ELECTROCARDIOLOGY, VOL. 7, NO. 1, 1974

VCG IN PML MYOCARDOPATHY

41

TABLE 3 Vectorcardiographic T Loop Parameters Maximal T Vector Directions Frontal Plane

QRS-T Angle

Maximal T Magnitude

Normal

60 (70.6%)

A:26 B:34

62 (74.7%)

A:29 B:33

45 (54.2%)

A:21 8:24

Abnormal

25 (29.4%)

A:13 B:12

21 (25.3%)

A: 8 B:13

38 (45.8%)

A:17 B:21

Normal

67 (78.8%)

A:31 B:36

65 (89%)

A:29 B:36

36 (45%)

A:18 8:18

Abnormal

18 (21.2%)

A: 7 B:11

8 (11%)

A: 5 B: 3

44 (55%)

A:19 B:25

Normal

51 (58.6%)

A:23 B:28

54 (66.7%)

A:12 B:42

48 (55.8%)

A:24 B:24

Abnormal

36 (41.6%)

A:17 B:19

27 (33.3%)

A:24 B: 3

38 (44.2%)

A:15 B:23

Left Sagittal

Transverse Plane

A = age 39 yrs or less B = 40 yrs or more

t e n t with these findings. The coronary arteries were found to be p a t e n t though t he y were often tortuous w i t h a "cork-screw" configuration. The significance of these T wave (T vector) abnormalities m a y be viewed in the context of t h e m y o c a r d i a l changes because of a h i g h incidence of v e n t r i c u l a r a s y n e r g y and freq u e n t association of a r r h y t h m i a s . Familial incidence, female preponderance, and freq u e n t association of cardiac anomalies and anomalies of coronary arteries m ay suggest a congenital n a t u r e of this syndrome. 25 A prim a r y muscle disorder such as m a l a l i g n m e n t of muscle bundles is conceivable. It is also possible t h a t th e prolapsing m i t r al valve with r e s u l t a n t tension at the chordae t e n d i n e a e a n d p a p i l l a r y m us c l e s m a y produce myocardial changes. The existing data t hus far shed no light on the mechanisms with which these T vector abnormalities are produced, b u t wh en the vent r i c ul a r abnormalities are t a k e n into account, it seems fair to state t h a t these p r i m a r y T vector abnormalities are not ischemic and t h a t t he y are related to some myocardial changes of yet ill-defined etiology. REFERENCES 1. BEHAR,V S, WHALEN, R E, AND McINTOSH, H D: The ballooning mitral valve in patients with "precordial honk" or "whoops". Am J Cardiol 20:789, 1967 J. ELECTROCARDIOLOGY, VOL. 7, NO. 1, 1974

2. KITTREDGE, R, SHIMOMURA, S, CAMERON, A, ANDBELL,A L L: Prolapsing mitral valve leaflets: Cineangiographic demonstration. Am J Roentgen 109:84, 1970 3. ENGLE, M A: The syndrome of apical systolic click, late systolic murmur and abnormal T waves. Circulation 39:1, 1969 4. TAVEL,M E, CAMBELL,R W, ANDZIMMER,J F: Late systolic murmur and mitral regurgitation. Am J Cardiol 15:719, 1965 5. SEGAL,B, ANDLINKOFF, W: Late systolic murmur of mitral regurgitation. Am Heart J 67:757, 1964 6. GOOCH,A S, MARANHAO,V, SCAMPARDONIS,G, CHA, S, ANDYANG, S S: Prolapse of mitral and tricuspid valves in systolic murmur-click syndrome. New Eng J Med 287:1218, 1972 7. GoocH, A S, VICENCIO, F, MARANHAO,V, AND GOLDBERG,H: Arrhythmia and left ventricular asynergy in the prolapsing mitral leaflet syndrome. Am J Cardiol 29:611, 1972 8. EHLERS, K H, ENGLE, M A, LEVINE, A R, GROSSMAN, H, AND FLEMING, R: Left ventricular abnormality with late mitral insufficiency and abnormal electrocardiogram. Am J Cardiol 26:333, 1970 9. JERESATY,R M: The syndrome associated with mid-systolic click and/or late systolic murmur. Chest 59:643, 1971 10. POCOCK,W A, AND BARLOW,J B: Postexercise arrhythmias in the billowing posterior mitral leaflet syndrome. Am Heart J 80:740, 1970 11. SLOMAN, F, WONG, M, AND WALKER, J: Arrhythmias on exercise in patients with abnormalities of the posterior leaflet of the mitral valve. Am Heart J 83:312, 1972

42

CHA ET AL

12. LEACHMAN, R, DEFRANCHESCHI, A, AND XAMALLOA, 0: Late systolic m u r m u r s and clicks associated with abnormal mitral valve ring. Am J Cardiol 23:609, 1969 13. SILVERBERG,S M: A quantitative study of the F r a n k vectorcardiogram: A comparison of younger and older normal populations. Am J Cardiol 18:672, 1966 14. MCCALL, B W, WALLACE, A G, AND ESTES, E H: Characteristics of the normal vectorcardiogram recorded with the Frank lead system. Am J Cardiol 10:514, 1962 15. DRAPER, H W, PEFFER, C J, STALLMAN, F W, LITLMANN, D, AND PIPBERGER, H V: The corrected orthogonal electrocardiogram and vectorcardiogram in 510 normal men. Circulation 30:853, 1964 16. BRISTOW, J D: A study of the normal Frank vectorcardiogram. Am Heart J 61:242, 1961 17. GUNTHER, L, AND GROF, W S: The normal adults spatial vectorcardiograms. Am J Cardiol 15:656, 1965 18. HOFFMAN,I, TAYMER, R, AND KITELL, I: T Loop rotation in ischemic heart disease. In Vectrocardiography, Vol. 2, edited by HOFFMAN, I. Lippincott Co, New York, 1971, p 181 19. SURAWICZ, B: The pathogenesis and clinical significance of primary T wave abnormalities.

In Advances in Electrocardiography, edited by

20.

21.

22. 23.

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25.

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J. ELECTROCARDIOLOGY, VOL. 7, NO. 1, 1974