Idiopathic hypertrophic cardiomyopathy involving the right ventricle

Idiopathic

Hypertrophic

Involving DOLORES

bvl.

Cardiomyopathy

the Right

Ventricle*

FALC:ONE, hi.~., DOUGLAS MOORE, M.D. and EDWARD C. LAMBERT, M.D. Buffalo, New York

murmur. The peripheral pulses and blood pressure measurements were normal. The electrocardiogram (Fig. 1A) indicated moderate right ventricular hypertrophy with marked right axis deviation. The chest roentgenogram (Fig. 2-4) revealed a moderately enlarged heart (cardiothoracic ratio of 60%) and normal vascuiarity. The patient has remained asymptomatic and active during the period of observation. Clinical findings did not change during this time. Right-sided card& catheteruation was performed at age 8 years (1958). This study failed to reveal an intracardiac shunt or a significant pressure gradient across the right ventricular outflow tract. The pressures obtained from the right heart were normal (Table I). In a further effort to determine the diagnosis, a second right heart catheterization with selective angiography was performed in 1959. On this occasion a high-pressure area was entered in the region of the apex of the right ventricle, where there was a marked decrease in the oxygen saturation of the blood (Table I). There was no significant pressure gradient across the pulmonary valve or right ventricular outflow tract. On a selective biplane angiogram there was a filling defect in the region of the apex of the right ventricle; the outflow tract was normal. On the basis of this study, abnormal partitioning of the right ventricle was suspected. The patient continued asymptomatic until age 15 (1965), when he noted exertional dyspnea. Symptoms of angina, syncope, or arrhythmia were not present. ‘The cardiac murmur was not changed. The electrocardiogram (Fig. 1B) continued to show evidence of marked right ventricular hypertrophy, and the chest roentgenogram displayed evidence of cardiac enlargement (Fig. 2B). A vectorcardiogram was obtained at this time (Fig. 3) and demonstrated the mid-forces to be abnormally rightward, superior and anterior, with terminal slowing and a counterclockwise frontal vector loop. Blood studies disclosed normal values for the erythrocyte sedimentation rate, serum glutamic oxaloacetic transaminase, serum glu-

DIOPATWX hypertrophic cardiomyopathy involves the ventricular septum and frequently the free walls of the right and left ventricles, Outflow obstruction of the left ventricle is the usual hemodynamic finding and may be associated with outflow obstruction of the right ventricle of a lesser degree.le4 Recently it has been recognized that an isolated area of high pressure at the right ventricular apex may occur in the absence of a gradient across the right ventricular outflow tract.5 However, it is rare to find such involvement of the right ventricle in the absence of pressure gradients across the left ventricular outflow area. The patient to be described is therefore unusual in that he has displayed evidence of He has isolated right-sided cardiac involvement. been observed now for 14 years without evidence of significant change in his clinical or hemodynamic status. The initial cardiac catheterization failed to demonstrate an isolated area of high pressure, but subsequently it was demonstrated at the apex of the right ventricle, from which blood with a low oxygen content was obtained.

I

CASE HISTORY a 16 year old white boy, was first His previous medical seen in 1952 at age 21 months. history, growth and development had been without incident with the exception that a heart murmur had appeared at 18 months of age. There was no familial history of congenital heart disease or of sudden death in relatives. On physical examination the only significant finding was a harsh, loud, ejection systolic murmur at the lower left sternal border and apex. The heart sounds were of normal intensity, no thrills were palpable, and there was no ejection click nor diastolic

The patient,

* From the Children’s Hospital of Buffalo and the Department of Pediatrics, State University of New York at Buffalo School of Medicine. This study was supported by Grant Tl-HD-39 from the National Institutes of Health, U. S. Public Health Service. Dr. Falcone was a postdoctoral research fellow, National Heart Institute, U. S. Public Health Service. VOLUME 19,

MAY

1967

735

736

Falcone,

Moore

and Lambert

FIG. 1. Electrocardiograms taken (A) at the age of 21 months (paper speed 25 mm./sec.) and (B) at the age of 15 years (paper speed 50 mm./sec.). Right ventricular hypertrophy is evident on both tracings together with progressive right axis deviation.

B

:1

Chest roent~genograms taken at age 21 months (A) and at 15 years (B). cardiomegaly. The cardiothoracic ratio in .2 is GO’;&and in B, 547,. FIG.

2.

tamic pyruvic transaminase, C-reactive protein and lactic acid dehydrogenase. A third diagnostic study, which included right and left heart catheterization and selective cineangiography, was then performed. The high-pressure area in the region of the apex of the right ventricle was entered on four

Both indicate moderate

The blood oxygen saturation in this area occasions. was again found to be decreased in three serial The right atria1 pressure tracings were norsamples. The pressure tracing obtained in the abdominal mal. aorta (Fig. 4) showed a “bisferiens” notch and a rapid upstroke time (0.08 sec.). The right and left THE

AMERICAN

JOURNAL

OF

CARDIOLOGY

Cardiomyopathy

Involving

the Right

737

Ventricle

FIG. 3. (age

V&orcardio,qam obtained at the time of the third cardiac rathcterization .\ 1 mv. reference standard The Frank Icad system was utilized. 15 yr.).

peared deformed by a thickened flow obstruction was seen.

septum,

but no out-

DISCUSSION Pressure gradients within the right ventricle between the inflow area and the right ventricular outflow tract are not uncommonly found in patients with idiopathic hypertrophic cardiomyopathy when there is predominant involvement of the left ventricular outflow area.’ ,2,6,7 Recently

FIG. 4. Pressure cum fromthe abdomnol aorta. ing shows a “bisferiens” pulse and sharp T = “tidal” wave; D = dicrotic notch.

The tracupstroke.

ventricular pressure curves did not display upstroke notches, and the postextrasystolic aortic pressures were not decreased. There was no gradient across the left ventricular outflow or the aortic valve at rest. Intravenous infusion of isoproterenol was followed by an increase in systolic pressure of the right ventricular apex, while the aortic pressure remained unchanged. The administration of levarterenol produced proportionately similar increases in systolic pressure in the right ventricular apex as in the left ventricle (Fig. 5). Cineangiograms were obtained following low-pressure injection of : 0 cc. of contrast media into the apex of the right ventricle. There was a narrow communication between the apex and the inflow area of the right ventricle (Fig. 6). This channel appeared to be obliterated during systole and was elongated and narrow in diastole. There was an adequate right ventricular outflow area, although the septum appeared thickened and bulged into the cavity of the right ventricle. On recirculation through the left side of the heart, the cavity of the left ventricle apVOLUME

19. MAY1967

FIG. 5. Simultaneous pressure recordiqs with catheters in the right ventricular apex and in the left ventricle following the administration of levarterenol.

Falcone,

738

Moore

and

TABLE

Cardiac January 1958 Blood 02 Pressure Sat. (5,) (mm. Hg) Superior vena cava Right atrium Right ventricular inflow Right ventricular outflow Right ventricular apex Pulmonary artery Aorta Left ventricle Systemic artery

77 66 72 70

21’j1’2*

98

114/57

I

Catheterization

Data

October Blood 02 Sat. (%)

6-9* 29/3 21/3*

71’

Lambert

74 73

1959 Pressure (mm. Hg)

3-6

45,30 68 98

24/8 87/10 20/10 92/67 90,‘8

December 1965 Blood 0s Pressure Sat. (o/;) (mm. llg) 73 76 73 70,74 57,46, 73 97

M (2) M (2) t9/3 81/4,78/2 20/l 1 83/55+ 83/6* 88/52

50

* Pullback recording. M = mean blood pressure.

a few patients have been reported in whom little or no obstruction to right ventricular outflow could be demonstrated, although a gradient was present between the apex and the inflow area of the right ventricle. Goodwin6 noted that the right-sided gradients in his patients often lay between the apex of the right ventricle and the right ventricular outflow tract, rather than between the right ventricular outflow and the pulmonary valve. His patients were found to have left-sided gradients as well. Lockhart and associates5 found a significant gradient between right ventricular inflow and outflow in only 3 of 13 patients but were able to define an

FIG. 6. Composite diagram drawn from 16 mm. cineangiographic frame recorded in diastole at the time of the third cardiac catheterization. The tip of the catheter lies in the apex of the right ventricle (A), through the narrow communicating channel between the apex (A) and the inflow area (I). This channel was obliterated in systole by the septal mass (S) lying to the left of the channel. The outflow area of the right ventricle (0) is not obstructed.

area of high pressure at the right ventricular All of the patients apex in 8 of their 13 cases. who had left heart catheterizations had gradients across the left ventricular outflow area at rest Taylor and his or after isoproterenol infusion. colleagues* noted 4 patients with idiopathic hypertrophic cardiomyopathy, 3 of whom had high pressure areas at the right ventricular apex, without significant gradients between the pulmonary artery and the right ventricular inIn 1 of these patients, as in our fundibulum. case, it was possible to withdraw a catheter from the pulmonary artery to the right atrium without passing through the high-pressure area. In another patient there was no left-sided obstructive gradient recorded. Recently Criley and his associates9 have questioned the significance of high pressures recorded in the left ventricle in patients with idiopathic hypertrophic cardiomyopathy. They suggested that systolic obliteration of the left ventricular cavity could provide an explanation It is for the pressure gradient in this condition. possible that the high pressures recorded at the right ventricular apex in our patient are produced by muscular contraction around the catheter tip in systole, and that the increase in pressure observed after isoproterenol infusion directly reflects an increase in the rate and degree of right ventricular emptying; the mechanism of response is similar to that thought by Criley to occur in the left ventricle following Steiner,lO in a disadministration of this drug. cussion of right ventricular angiograms in patients with idiopathic hypertrophic cardiomyopathy, noted that pockets of contrast material frequently formed between hypertrophied musTHE

AMERICAN

JOURNAL

OF

CARDIOLOGY

Cardiomyopathy cle masses and then became

Involving

isolated from the rest of the ventricular cavity. He suggested that sllch areas may produce abnormal pressures that can bc recorded at right heart catheterization. Diagrams of his right ventricular angiograms were included in the report by Cohen of the and others,’ and in 3 the configuration right ventricular cavity resembled that found in our patient. The low blood oxygen saturation at the right ventricular apex in our patient may be due to blood trapped in the cul-de-sac created by the isolated right ventricular apex. Clinical Diagnosis: The realization that large presslu-e gradients may be recorded within the right ventricle in patients with hypertrophic cardiomyopathy is important. In those patients with septal hypertrophy manifested only by right-sided involvement, the findings may be ascribed to the presence of aberrant muscle bands, and the correct diagnosis may remain unrecognized. The two-chambered right ventricle is a congenital anomaly characterized by the presence of hypertrophied muscle bands which bisect the right ventricle and cause partition.” This results in an obstructive gradient between the inflow and outflow areas of the right ventricle.” During cardiac catheterization the localization of an elevated pressure area to the right ventricular inflow suggests the presence of a double-chambered right ventricle. Differentiation can best be made by analysis of the right ventricular angiogram. In the twochambered ventricle the site of obstruction is visible as a constant filling defect between the inflow area and outflow tract. The presence of septal hypertrophy, elongation of the right ventricular cavity and of infundibular stenosis suggests idiopathic hypertrophic cardiomyopathy. Moreover, the association of the doublechambered right ventricle with other congenital cardiac defects aids in its differentiation. Idiopathic cardiomyopathy is rarely found in combination with congenital heart defects,’ *13 whereas the two-chambered right ventricle is most commonly associated with a ventricular septal defect’l ,I4 or pulmonary valvar stenosis.15 Other congenital defects may also be present. In any single patient, however, the right ventricular angiogram best distinguishes the twochambered right ventricle from idiopathic hypertrophic cardiomyopathy. The patient we have described is believed to have an unusual manifestation of idiopathic hypertrophic cardiomyopathy. The high-pressure area at the right ventricular apex and the VOLL!ME19.

MAY

1967

the Right

Ventricle

739

lack of a gradient across the left ventricular outflow area at rest are unusual features. The electrocardiogram showed evidence of marked right ventricular hypertrophy. Although Hollister and Goodwin’6 and Cohen and his colleagues’ reported on a patient with evidence of right ventricular hypertrophy in the electrocardiogram, their case differed from ours in that there were significant pressure gradients across the left and right ventricular outflow tracts. The vectorcardiographic findings in our patient are also unlike those described in patients with idiopathic hypertrophic cardiomyopathy. These vectorcardiograms have displayed evidence of left ventricular hypertrophy, myocardial infarction, or of intraventricular conduction defects.” Blood oxygen desaturation at the right ventricular apex has not to our knowledge been previously reported. Finally, we have observed our patient for 14 years, during which his clinical and hemodynamic status has remained remarkably stable. We have assumed that our patient has idiopathic hypertrophic cardiomyopathy with findings that appear to involve only the right heart. Even though no left ventricular pressure gradient was found, there may also be involvement of the left ventricle, which will become apparent at The short arterial upstroke some future time. time and arterial “bisferiens” tracing suggest some left ventricular involvement. As our experience demonstrates, the diagnosis may be missed even at cardiac catheterization since, unless the isolated area of high pressure at the apex is entered, the hemodynamic findings may appear to be normal. Under these circumstances the value of selective right ventriculography in reaching the correct diagnosis cannot be overemphasized. SUMMARY A 16 year old boy has been followed up since 1952. Though he now experiences slight exertional dyspnea, his cardiac status has not changed during this 14 year period. The clinical and catheterization data indicate that this patient represents a case of idiopathic hypertrophic cardiomyopathy that involves the septum and has produced narrowing of the apex of the right ventricle. Marked blood oxygen desaturation and elevated pressures were found at the right ventricular apex and are believed to be due to systolic obliteration and isolation of the apex by muscular contraction. No obstruction to pulmonary tlow was found, and

Falcone,

740

Moore

there was no gradient across the left ventricular outflow tract at rest. Our findings are similar to some observations made by others in patients with idiopathic hypertrophic cardiomyopathy, and different from reported cases of doubleThey indicate that chambered right ventricle. idiopathic hypertrophic cardiomyopathy represents a wide spectrum of manifestations and may involve predominantly the right ventricle. REFERENCES 1. BRAUNWALD, E., LAMBREW, C. T., ROCKHOFFI S. D., Ross, J., JR. and MORROW, A. G. Idiopathic hypertrophic subaortic stenosis. I. A description of the disease based upon an analysis of 64 patients. Circulation, 30 (Suppl. 4): 3, 1964. 2. WIGLE, E. D., HEIMBECKER,R. 0. and GUNTON, R. W. Idiopathic ventricular septal hypertrophy causing muscular subaortic stenosis. Circulation, 26: 325, 1962. In: 3. BRIGDEN,W. Discussion of D. Teare’s paper. Cardiomyopathies, Ciba Foundation Symposium, p. 20. Edited by WOLSTENHOLME,G. E. W. and O’CONNOR, M. Boston, 1964. Little, Brown & Company. 4. GOODWIN,J. F., HOLLMAN,A., CLELAND,W. P. and TEARE, D. Obstructive cardiomyopathy simulating aortic stenosis. Brit. Heart J., 22: 403, 1960. 5. LOCKHART,A. et al. Right ventricular involvement in obstructive cardiomyopathies: Haemodynamic studies in 13 cases. Brit. Heart J., 28: 122, 1966. 6. GOODWIN, J. F. Cardiac function in primary myocardial diseases. Brit. M. J., 1: 1527, 1559, 1964. 7. COHEN, J., EFFAT, H., GOODWIN, J. F., OAKLEY, C. M. and STEINER,R. E. Hypertrophic obstruc-

and

Lambert

tiverardiomyopathy. Brat. Heart J., 26: 16, 1964. 8. TAYLOR, R. R., BERNSTEIN, L. and JOSE,A. D. Obstructive phenomena in ventricular hypertrophy. Brit. Heart J., 26: 193, 1964. 9. CRILEY, J. M., LEWIS, K. B., WHITE, R. F., JR. and Ross, R. S. Pressure gradients without obstruction. A new concept of “hypertrophic subaortic stenosis.” Circulation, 32: 881, 1965. 10. STEINER,R. E. Radiology of hypertrophic obstructive cardiomyopathy. In Ref. 3, p. 233. 11. HARTMANN, A. F., TSIFUTIS, A. A., ARVIDSSON,H. and GOLDRING, D. The two-chambered right ventricle: Report of nine cases. Circulation, 26: 279, 1962. 12. COATES, J. R., MCCLENATHAN, J. E. and SCOTT, L. P. The double-chambered right ventricle: A diagnostic and operative pitfall. Am. J. Cardiol., 14: 561, 1964. 13. KING, S. M., VOGEL, J. H. K. and BLOUNT, S. G. Idiopathic muscular subvalvar aortic stenosis with associated congenital cardiovascular lesions. Am. J. Cardiol., 15: 837, 1965. 14. LUCAS, R. V. et al. Anomalous muscle bundle of the right ventricle: Hemodynamic consequences and surgical considerations. Circulation, 25: 443, 1962. 15. WARDEN, H. E., LUCAS, R. V. and VARCO, R. L. Right ventricular obstruction resulting from anomalous muscle bundles. J. Thoracic G? Cardiouas. Surg., 51: 53, 1966. 16. HOLLISTER,R. M. and GOODWIN,J. F. The electrocardiogram in cardiomyopathy. Brit. Heart J., 25: 357, 1963. 17. BANTA, H. D. and ESTES, E. H. Electrocardiographic and vectorcardiographic findings in patients with idiopathic myocardial hypertrophy. Am. J. Cardiol., 14: 218, 1964.

THE AMERICANJOURNAL OF CARDIOLOGY