Double-chambered right ventricle due to fibromuscular diaphragm

April,

792

Brief

Communications

separation between inner and outer layers, suggestinga false lumen. Oscillating echoes,felt to represent movement of intimal flaps, have been visualized within the true and false lumens of the aorta.&’ Pericardial effusion, diastolic mitral valve fluttering due to aortic regurgitation, and premature mitral valve closure, generally seen following the development of acute, severe aortic regurgitation, may alsobe identified but are not specificfor aortic dissection. Our patient demonstrated appreciable aortic root enlargement. However, thickening of the anterior and/or posterior aortic walls of a magnitude suggestiveof dissection was not present, and no parallel aortic wall echoes could be visualized throughout systoleand diastole. Other interesting abnormalities were, however, observed.Echoes openingalmost to the outer edgesof the dilated aortic root in systole and collapsinginward during diastole were seen prominently on both M-mode and 2DE scans.Although their movement wassimilar to that of aortic leaflets, their remarkably wide systolic separation of up to 41 mm and their excessive length were unusual features for aortic leaflets, even in associationwith severe aortic regurgitation. Movement of a partially dehisced intimal flap was therefore consideredlikely. The echowhich prolapsedinto the left ventricle during diastole wascontinuous with the abnormally elongated echoeswithin the aortic root and was thought to represent flail movement of an unsupported aortic valve cusp and/or prolapse of a partially dehiscedaortic intimal flap. The operative findings suggestedthat the intimal flap, together with an aortic leaflet, produced this abnormal diastolic intracavitary echo. Echocardiographic findings of diastolic echoeswithin the left ventricular outflow tract are most commonly associated with aortic valve endocarditis, due to prolaspeof a torn aortic cusp or vegetation into the left ventricle.“’ Indeed, the M-mode echocardiogram at the other hospital had been interpreted to represent endocarditic vegetations. This caseillustrates that prolapse of aortic intima due to aortic root dissection must be consideredin the differential diagnosisof diastolic echoesprolapsingfrom the aortic root into the left ventricle. The findings in this case broaden the spectrum of echocardiographic findings which may be observed with dissection of the ascending aorta. REFERENCES 1. Brown 2.

3.

4.

5.

OR, Popp RL, Kloster FE: Echocardiographic criteria for aortic root dissection. Am J Cardiol 36:17, 1975. Matsumoto M, Matsuo H, Ohara T, Yoshioka Y, Abe H: A two-dimensional echocardiographic approach to dissecting aneurysms of the aorta to prevent false-positive diagnoses. Radiology 127:491, 1978. Roller DH, Muna WF, Ross AM: Psoriasis, sacroiliitis and aortitis: An echocardiographic mimic of aortic root dissection. Chest 75:641, 1979. Kolettis M, Toutouzas P, Avgoustakis D: False echocardiographic diagnosis of aortic root dissection in case of abdominal aortic dissection. Br Heart J 45:602, 1981. Krueger SK, Starke H, Forker AD, Eliot RS: Echocardiographic mimics of aortic root dissection. Chest 67:441, 1975.

American

Heart

1984 Journal

6. Nicholson WJ, Cobhs BW Jr: Echocardiographic oscillating flap in aortic root dissecting aneurysm. Chest 70:305, 1976. 7. D’Cruz IA, Jain M, Campbell C, Goldbarg AN: Ultrasound visualization of aortic dissection by right parasternal scanning, including systolic flutter of the intimal flap. Chest 80:239, 1981. 8. Nanda NC: Aortic root dissection: Unusual echocardiographit motion pattern (letter). Ann Intern Med 85:79, 1976. W-L, Peticlerc R, Dyrda I, Winsherg F: Echographic 9. Curati demonstration of mobility of the dissecting flap of an aortic aneurysm. Radiology 123:173, 1977. 10. Wray TM: The variable echocardiographic features in aortic valve endocarditis. Circulation 52:658, 1975.

Double-chambered right ventricle fibromuscular diaphragm

due to

Tali T. Bashour, M.D., Sami Kabbani, M.D., Aref Sandouk, M.D., and Tsung 0. Cheng, M.D. Damascus,

Syria,

and Washington,

D.C.

There have been several reports’ ’ in recent years of the so-called double-chambered right ventricle (RV). The usual finding wasa systolic pressuregradient between the RV sinus and the subpulmonic region resulting from an obstructing hypertrophic muscular band. The latter was usually identifiable either with a displacedhypertrophied moderator band related to the anterior papillary muscleor with a giant septoparietal band inserted to the anterior free wall. There was usually an associated ventricular septal defect (VSD), either above or below the band. A double-chamberedRV due to an obstructing fibromuscular diaphragm has not been reported to the best of our knowledge.We report such a case,its clinical features, and its successfulsurgical outcome. A 41-year-old man wasadmitted to Mouassat University Hospital in May, 1981, with a history of exertional dyspneaof 2 years’ duration. A precordial systolic murmur was previously thought to be due to a small VSD. On physical examination blood pressurewas 140/80 mm Hg, pulse was 80/min, and no cyanosis or clubbing was evident. A systolic thrill was palpable at the mid and lower left parasternal area. A grade % pansystolic murmur was heard best in the fifth left intercostal spaceat the sternal border. Its intensity at this location was clearly increased during inspiration and after the inhalation of amyl nitrite. The secondheart sound was normally split and of usual intensity. The rest of the physical examination was unremarkable. The ECG revealed mild right axis shift (+llO degrees) but was otherwise normal. Chest x-ray film revealed normal heart size and slight increasein pulmoFrom the Department of Medicine, Division of Cardiology, Damascus University School of Medicine; and the Department of Medicine, Division of Cardiology, The George Washington University Medical Center. Reprint requests: Tsung 0. Cheng, M.D., sity Medical Center, 2150 Pennsylvania 20037.

The George Washington UniverAve., N.W.. Washington, DC

Volume Number

107 4

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Communications

793

Fig. 2. Operative view through the right ventriculotomy showingthe fibromuscular diaphragm. 1. Right ventriculogram in right anterior oblique projection. Arrows indicate the obstructing diaphragm which divides the right ventricle into a larger proximal chamber (PRV) and a smaller distal chamber (DRV). PV = pulmonic valve; PA = pulmonary artery. Fig.

Table

I. Cardiac catheterization findings Site

SVC RA

Pressure (mmHg) Oxygen saturation ( 7; ) WC = superior PA = pulmonary Mean pressures

(10) 14

(10) 13

Proximal RV

Distal RV

100

28

318)

8 19

19

10 74

vena cam; RA = right artery; LV = left ventricle; within parentheses.

PA

atrium; RV = right A0 = aorta.

LV A0 150 -

150 8 100 98 98

ventricle;

nary vascularity. At cardiac catheterization pulmonary artery and RV infundibular pressureswere normal, a 72 mm Hg midventricular systolic gradient wasfound (Table I). Blood oxygen saturation study was consistent with a small left-to-right shunt at the midventricular left (Table I). Multiple RV injections in anteroposterior and oblique views revealed marked annular narrowing in mid RV (Fig. l), with trabeculated chambersproximal and distal to the obstruction. The infundibular area and pulmonic valve were normal. A left ventricular injection in the left anterior oblique view outlined a small left-to-right shunt via a subcristal defect. At operation a discrete fibrous diaphragm with thick muscular basewas seen(Fig. 2). It was attached to the anterior wall of the RV and the septum. By traversing the RV cavity it divided it into unequal halves, the distal being slightly smaller than the proximal. The membranewas excised(Fig. 3), and a small 8 mm subcristal VSD was also closed. Postoperative course was uneventful, and the heart murmur disappeared.

Fig. 3. Operative view through the right ventriculotomy

after partial excision of the diaphragm. Double-chambered RV is a rare congenital cardiac anomaly which became recognized only during the past two decades.‘-7It is due in most casesto an anomalous muscle bundle resulting from the elevated origin of a hypertrophied moderator band.1,4.5 Occasionally the anomalousbundle could be identified, not with the moderator band, but with one of the accessoryseptoparietal bands that at times are present in normal hearts7 Pathologic studieshave suggestedthat the embryologic aberration is failure of normal bulbar incorporation into the RV body.5 OtherG4 attributed the anomaly to persistenceof early myocardial cells or trabeculations. VSD is a common associatedlesion314 usually located distal to the obstruction, an arrangement permitting left-to-right shunt. A tetralogy of Fallot type of physiology may be present in a few patients.5*6The diagnostic features on cardiac catheterization and angiography are mid RV pressuregradient, angiographic filling defect below the infundibulum with trabeculated portions proximally and distally, and leftto-right

shunt at midventricular

leve1.5 The clinical

find-

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Brief Communications

American

April, 1984 Heart Journal

ings can be misleading and may simulate those of isolated VSD or pure RV outflow obstruction. In our patient the increased intensity of the systolic murmur during inspiration and briefly after inhalation of amyl nitrite militates against an uncomplicated VSD, and is consistent with RV outflow obstruction. The components of the murmur contributed by the VSD must have been overshadowed by those originating at the obstruction. Unlike the classical pathology described in other reports, the dividing structure in our patient was a fibrous diaphragm with muscular anulus similar to that seen in discrete subaortic stenosis. This anatomic resemblance may be of more than passing interest, since discrete subaortic stenosis has been described in associationwith double-chamberedRV.” REFERENCES

I. Lucas RV, Varco RL, Lillehei CW, Adams P, Anderson RC, Edwards JE: Anomalous muscle bundle of the right ventricle. Hemodynamic consequences and surgical considerations. Circulation 25:443, 1962. 2. Hartmann AF Jr, Tsifutis AA, Arvidsson M, Goldring D: The two-chambered right ventricle. Report of nine cases. Circulation 26:279, 1962. 3. Gale GE, Heimann KW, Barlow JB: Double-chambered right ventricle. A report of five cases. Br Heart J 31:291, 1969. 4. Forster JW, Humphreys JO: Right ventricular anomalous muscle bundle. Clinical and laboratory presentation and natural history. Circulation 43:115, 1971. 5. Rowland TW, Rosenthal A, Castaneda AR: Double-chamber right ventricle: Experience with 17 cases. AM HEART J 89:455, 1975.

6. Perloff JK, Ronan JA Jr, De Leon AC: Ventricular septal defect with the “two-chambered right ventricle.” Am J Cardiol 162394, 1965. 7. Gallucci V, Scalia D, Thiene G, Mazzucco A, Valfre C: Double-chambered right ventricle: Surgical experience and anatomical considerations. Thorac Cardiovasc Surg 28:13, 1980.

Multiple systolic clicks and echographic coarse systolic fluttering with porcine valve malfunction Roman L. Szkopiec, M.D., Rajendra D. Savajiyani, M.D., Kenneth B. Desser,M.D., and Albert0 Benchimoi, M.D. Phoenix, Ark Valvular dysfunction has been demonstrated to occur in patients with the Hancock porcine bioprosthesis.1-4 Calcification of the xenograft, fibrosis, and tissuefailure are the major mechanismsof primary valvular malfunction.’ We suggestthat coarsesystolic fluttering of the Hancock valve leaflet in the aortic position may be indicative of valve dysfunction if it appears in the absenceof a low output From the Institute for Cardiovascular Diseases, Good Samaritan Medical center. Supported in part by the E. Nichols Memorial Fund, and by the Institute for Cardiovascular Diseases, Inc. Reprint requests: Albert0 Benchimol. M.D., Good Samaritan Medical Center, P.O. Box -3989, Phoenix, AZ 85062.

Fig. 1. Simultaneously recorded phonocardiogramat the mitral (MA), tricuspid (TA), pulmonic (PA), and aortic areas (AA); external carotid arterial pulse tracing (CT) and lead II (Z,ZZ]of the ECG from patient No. 1. Note high amplitude systolic clicks recorded at all precordial sites. DN = dicrotic notch. state during the longitudinal follow-up of a patient. We alsoreport multiple loud systolic clicks in associationwith a tear of a Hancock valve leaflet in the mitral position. In the latter casecoarse systolic fluttering on the M-mode echocardiogram and discrete systolic echoesbehind the line of coaptation on the two-dimensionalechocardiogram were observed.The multiple loud systolic clicks appeared to be caused by coarse systolic vibrations of the xenograft. Case 1. A 66-year-old man with a mitral position Hancock valve wasadmitted to the hospital with a 3-week history of increasing shortness of breath and upper abdominal distress.Physical examination revealed cardiomegaly, a decreasedfirst heart sound amplitude, multiple loud systolic clicks (Fig. l), and an apical holosystolic murmur with radiation to the axilla. No diastolic murmur washeard. An M-mode echocardiogramof the mitral valve prosthesisdemonstrated coarsesystolic and diastolic fluttering and an increasedinitial diastolic slope of the stent (Fig. 2). The ultrasonic sector scan revealed discrete systolic echoesbehind the line of coaptation of the mitral leaflets. Cardiac catheterization disclosed severe mitral regurgitation without evidence of aortic regurgitation. The Hancock xenograft was replaced with a StarrEdwards prosthesis. Examination of the xenograft discloseda 1.1 cm tear of the muscular leaflet creating a hole of 1.1 X 0.4 cm. Case 2. A 44-year-old man with an aortic position Hancock valve was admitted to the hospital with a g-day history of dyspnea on effort, fatigue, and chest pain. Physical examination disclosedfindings consistent with pulmonary edema and severe aortic regurgitation. An M-mode echophonocardiogramdemonstrated coarsesys-