diagnosis and management parachute mitral valve ... · included supravalvar mitral stenosis,...

British Heart Journal, 1974, 36, 64I-652.

Diagnosis and management of parachute mitralvalve and supravalvar mitral ring

Fergus J. Macartney, Olive Scott, Marian I. Ionescu, and Philip B. DeverallFrom Killingbeck Hospital and The General Infirmary, Leeds

The results of investigation in 5 children with congenital deformities of the mitral valve region characteristicof the 'parachute mitral valve complex' were reviewed. Three patients had parachute mitral valve, i hadsupravalvar mitral ring, and i had both these lesions. Associated anomalies included ventricular septaldefect, double outlet right ventricle, subaortic stenosis, bicuspid aortic valve, and coarctation of the aorta.

Clinical presentation depended on which abnormality was dominant. However, all patients had clinical andhaemodynamic evidence of mitral valve disease: stenosis in 4 patients and incompetence in i. In i patient thesingle, hypertrophied papillary muscle obstructed left ventricular ejection, mimicking hypertrophic obstructivecardiomyopathy.

Parachute mitral valve produced a specific angiocardiographic abnormality, afilling defect during diastoleshaped like an egg-timer in the lateral left ventricular angiogram. This was produced by non-opacified bloodposterior to the mitral leaflets and chordae tendineae converging towards the filling defect produced by theenlarged, single papillary muscle.

Supravalvar mitral ring produced a thin, crescentic, filling defect between the left atrium and ventricle,seen in the lateral view during opacification of the ventriclefrom the atrium.

Careful preoperative assessment of the relative importance of these multiple anomalies allowed successfulsurgical correction of the significant lesions in the 4 patients operated on. Of 3 patients with parachute mitralvalve, 2 required mitral valve replacement. In i of these a supravalvar ring was also excised. In the otherpatient with supravalvar mitral stenosis, excision of the ring alone relieved mitral obstruction adequately.

Congenital obstructive anomalies in relation to theleft atrioventricular valve are a rare but importantcause of disability in infancy and childhood. Supra-valvar mitral ring has been reported by severalgroups (Rogers et al., I955; Johnson and Dodd,I957; Manubens, Krovetz, and Adams, I960;Lynch et al., I962; Shone et al., I963; Cassano,I964; Anabtawi and Ellison, I965; Rao etal., I969).Shone et al. (I963) described a complex of 'para-chute mitral valve, supravalvar ring of the leftatrium, subaortic stenosis and coarctation of theaorta,' in 8 cases. Most of these reports have de-scribed necropsy material, this, at least in part,resulting from the difficulties of establishing adiagnosis in life. The frequent association of othersignificant cardiovascular anomalies further com-plicates diagnosis.

This report is prompted by investigative andsurgical experience with 5 children, 4 of whom

Received 30 November I973.

underwent operation and survived open intracardiaccorrection of multiple anomalies. These anomaliesincluded supravalvar mitral stenosis, parachutemitral valve, subaortic stenosis, and ventricularseptal defect. Two of the cases in addition had apseudocoarctation of the aorta. One child haddouble outlet right ventricle with d-malposition ofthe great arteries. Apart from the surgical considera-tions, we believe this experience has suggested themeans of diagnosing and assessing these anomaliesbefore operation.

Subjects and methodsFive children, aged i month to 13 years, are described.Cardiac catheterization was carried out by standardtechniques. Intravascular pressures were measured froma point I0 cm above the catheterization table top. Calcu-lations of pulmonary and systemic flows and resistanceby the Fick method were based upon pressures andsaturations from the great arteries and great veinsmeasured either simultaneously or within five minutes

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642 Macartney, Scott, Ionescu, and Deverall

of one another in a steady state except in Case 5, whereconditions were unstable. Left atrial pressure was meas-ured directly in 2 patients and indirectly in the remain-der. The pulmonary capillary wedge pressure wasvalidated in each case by withdrawal of blood with anoxygen saturation >95 per cent. Pulmonary venoussaturation was assumed to be equal to systemic arterialsaturation except in the presence of an intracardiacright-to-left shunt (Case 2) where 95 per cent saturatedblood was withdrawn from the left ventricle just distalto the mitral valve, and assumed to represent pulmonaryvenous blood. Oxygen uptake was directly measured in 3patients (Kappagoda and Linden, I972), and assumed in

2 (LaFarge and Miettinen, I970). Because one patienthad functional subaortic stenosis, records of the re-mainder were analysed for post-extrasystolic diminutionof pulse pressure (Braunwald et al., 1964).Rapid biplane Elema angiocardiograms were recorded

with injection into various chambers, but in each case aleft ventricular injection was performed with i14-18 mlConray 420 per kg body weight.

Clinical, surgical, and pathological dataThe electrocardiographic, radiographic, and haemo-dynamic findings are summarized in Tables I to 3.

TABLE I Electrocardiographicfindings

Case Rhythm RAH LAH RVH LVH Frontal Frontal loop NotesNo. QRS axis

I Sinus + - + - + 1 2.0 Clockwise2 Sinus + - + - + I650 Clockwise3 Sinus + + - + +450 Counterclockwise T wave inversion

V5, 64 Episodes of sinus

arrest with nodal - - - + 0 Counterclockwise T wave inversionescape V4, 5, 6

5 Sinus - - + - + i8o' Clockwise

LAH=left atrial hypertrophy; LVH=left ventricular hypertrophy; RAH=right atrial hypertrophy; RVH=right ventricularhypertrophy.

TABLE 2 Chest x-ray findings: values graded out of 4

Case Cardiothoracic Right atrial Left atrial Main pulm. Periph. pulm. Upper lobe Aortic archratio enlargement enlargement artery vasculature pulm. vein

enlargement enlargement

I 0o55 +2 0 +2 Normal + I Left2 0'57 +2 0 + I + 3 +2 Left3 o58 +I +3 +2 Normal +I Left4 o-6i 0 0 0 + I 0 Left5 o-67 + I 0 0 +2 0 Left

TABLE 3 Haemodynamic data

Pressure (mmHg)

Case No. Right Right Pulmonary PA Left Left Left Ascendingatrium ventricle artery wedge atrium ventricle ventricle aorta

(body) (outflow)

I I/-3 70/0 55/40 30/22 - 70/2 70/2 70/402 6/-2 86/-i 80/63 30/20 I00/0Io0/o 83/6I3 (preop) 5/o 30/0 30/8 - I2/5 I96/I0* -3 (postop) 5/2 45/3 42/30 3I/I8 - I60/2 140/4 I40/834 14/2 40/0 40/20 25/8 240/8 I35/8 120/555 I/-6 34/0 30/10 6/1-6 102/29t 102/29t I26/59

* Post-extrasystolic pressures; t not simultaneous with LA.Qp= pulmonary blood flow, Qs= Systemic blood flow, Rp = total pulmonary resistance,Rpa= pulmonary vascular resistance, Rs = total systemic resistance.



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Parachute mitral valve complex 643

These are principally determined by which haemo-dynamic abnormalities dominated the clinical picture.Table 4 lists the abnormalities present in each patient inrough order of importance and summarizes surgicaltreatment. Oxygen saturations revealed a right-to-leftshunt in only one patient (Case 2). This was at ventric-ular level, and the systemic arterial oxygen saturationwas 69 per cent. Left-to-right shunts at ventricular levelwere demonstrated in Cases I, 2, and 4. The history,results of physical examination, angiocardiography, andoperation or necropsy are presented individually.

Case reportsCase i

This girl had been dyspnoeic upon exertion from birth,but not orthopnoeic, and her exercise tolerance was con-siderably reduced when she was first seen by us at 2years of age.

The physical signs were of isolated severe mitral sten-osis, and included a left parastemal lift, a palpable secondheart sound, a pulmonary ejection click, and a longapical mid-diastolic rumble with presystolic accentua-tion. The second heart sound was closely split, with aloud pulmonary component. There was no systolicmurmur, no mitral opening snap, and no abnormality ofthe pulses.

Selective retrograde left ventricular angiocardiographyindicated a large high ventricular septal defect, throughwhich the right ventricle and pulmonary artery opacified.Pulmonary venous return was normal to an enlargedleft atrium. Between the left atrium and left ventriclewas a constant, thin, crescentic filling defect which didnot move as mitral leaflets do (Fig. I). The mitral orificeappeared somewhat reduced in diameter. Two papillarymuscles were identified in the left ventricle and theappearance of parachute mitral valve (v.i.) was notpresent. No coarctation or subaortic stenosis was seen.

Open intracardiac operation (P.B.D.), using the deephypothermic circulatory arrest technique, was per-formed when she was 2 years old and weighed 8 kg. Asubcristal ventricular septal defect was exposed throughthe right atrium and closed with a patch. The atrial

septum was then opened and a supravalvar mitral ringfound with a 4 mm orifice. The shelf of thin tissue sur-rounded the mitral orifice and was closely related to andfused with the base of the mitral leaflets. The shelf was

FIG. I Case i. Lateral view of pulmonary venous

phase of selective left ventricular angiocardiogram.Contrast medium entered the pulmonary circulationvia a ventricular septal defect. The left atrium isgreatly enlarged and arrows demonstrate the thincrescentic filling defect presumed due to a supra-valvar mitral ring.

Femoral Response to Bloodflows Vascularartery post-extra- (I./mmin per m2) resistances

systolic beat (units m2)Qp Qs Qp/Qs Rp Rs Rpa Rp/Rs

65/40 Normal 3.7 2-5 1.5 12 20 5-6 o-671/60 Normal 5.4 3.I I-8 I5 26 9-9 o-692/46* Abnormal 2-6 2-6 I 5.7 23.3 2.7 0-25I55/70 Normal 2.7 2.7 I II-7 3I.5 I-5 0°480/52 Normal 4.3 3.6 I*2 6.3 20-7 I-9 0-3

Normal i.8 ix8 I I3 6 35.7 0-4



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TABLE 4 Summary of anomalies

Case Age at Anomalies Surgical procedureNo. operation

(yr)

I 2 Subcristal ventricular septal defect; supravalvar Transatrial patch repair of ventricularmitral ring septal defect;

excision supravalvar ring2 I3 Double outlet right ventricle with Intraventricular correction of double

d-malposition of the great arteries; outlet right ventricle;parachute mitral valve; excision supravalvar ring;supravalvar mitral ring; mitral valve replacement;mild subaortic muscular obstruction; resection of subaortic obstructionanomalous tricuspid valve;pseudocoarctation of the aorta

3 10 Parachute mitral valve; Mitral valve replacement;subaortic stenosis excision subaortic stenosis

4 6 Discrete subaortic stenosis; Aortic valvotomy;aortic valve stenosis (bicuspid); excision subaortic stenosisventricular septal defect;parachute mitral valve;pseudocoarctation of aorta

5 Preductal coarctation of aorta;parachute mitral valve;bicuspid aortic valve

excised as much as possible. The underlying mitral Case 2tissue looked normal though no clear view of the pap-illary muscle anatomy could be seen. This girl had a history of recurrent chest infections and

After correction the pressures were: left ventricle feeding difficulties in infancy. Cyanosis was first noted atiiolio mmHg, right ventricle 50/I0 mmHg, left atrium 9 months of age. She had been diagnosed as having(mean) 14 mmHg, right atrium (mean) I2 mmHg. Eisenmenger's complex after cardiac catheterization atThe child has done well, with increased growth and the age of 8 years. A prominent apical mid-diastolic

greatly increased effort tolerance. There is still a short murmur was noted at that time, but its origin could notapical mid-diastolic murmur and palpable right ven- be explained. She became progressively more cyanotic,tricle. and dyspnoeic on the slightest exertion, but never

FIG. 2 a) Case 2. Diagrammatic representation of Fig. 2 b), to demonstrate the components ofa parachute mitral valve. The chordae tendineae are drawn for clarification, but are not demon-strated angiocardiographically. The position of the ascending aorta and aortic valve are in partderivedfrom otherframes of the same angiocardiogram, as is the site of the ventricular septal defect.b) Case 2. Lateral view of selective left ventricular angiocardiogram during diastole. The in-jection was made through the lower catheter, which has traversed a ventricular septal defectfromthe right ventricle. A second catheter has been advanced into thepulmonary artery via the superiorvena cava and right heart. The 'egg-timer' appearance ofparachute mitral valve is seen as afillingdefect in the left ventricle. The ventricular septal defect lies well below both semilunar valves andmost of the contrast medium injected has entered the pulmonary artery. There is mitral-aorticdiscontinuity. c) Case 3. Selective left ventricular angiocardiogram. Lateral view of diastolicfilm. The enlarged single papillary muscle (PM) together with non-opacified blood trapped with-in the cone-shaped mitral leaflets (MV) make up the 'egg-timer'filling defect. There is moderateregurgitation of contrast medium into the enlarged left atrium. d) Case 5. Diastolic film: lateralprojection of selective left ventricular angiocardiogram. The 'egg-timer' deformity of the mitralvalve apparatus is demonstrated with black arrows.AO = ascending aorta, LC= left circumflex coronary artery, LV= left ventricle, MV= mitral

valve, PA =pulmonary artery, PM= papillary muscle, RV= right ventricle, V= ventricularseptal defect.



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orthopnoeic, and had had several episodes of angina-likepain.On physical examination at the age of 13 years she was

severely cyanosed, with pronounced digital clubbing.The peripheral pulses were normal, but her jugularvenous pressure was i cm above the sternal angle at 450,with the 'a' and 'v' waves of equal height. There wassevere right ventricular hypertrophy on palpation, withboth heart sounds palpable. The first and second heartsounds were single. At the lower left sternal border therewas a long, early systolic murmur of moderate intensity.There was also a very loud apical mid-diastolic murmurwith presystolic accentuation but no snap.

Selective anterograde right and left ventricular, andretrograde aortic root angiograms were performed. Withthe catheter through a ventricular septal defect, a nor-mally situated left ventricle was seen, from which theonly exit was a large ventricular septal defect which waswell below both semilunar valves (Fig. 2b). The mitralvalve was displaced somewhat downward from itsnormal position, and the leading edge of the anteriorleaflet as seen in the frontal projection was unusuallycurved. In the lateral projection during diastole the 'egg-timer' appearance of parachute mitral valve was clearlyseen (Fig. 2b). There was a well-developed bilateralconus and the aortic valve lay somewhat above and

a bFIG. 3 a) Case 2. Lateral projection, retrograde aortogram. A second transvenous catheterlies in the pulmonary artery. There is a pseudocoarctation (C) associated with pronounceddistortion of the aortic isthmus, and an aortic ductus diverticulum (*). The presence of aortic/mitral discontinuity is demonstrated by the two white arrows, one pointing to the aortic annulus,and the other to the kink in the greatly enlarged circumflex left coronary artery, at the pointwhere it passes into the atrioventricular groove. This is an external landmark of the mitralannulus. This interpretation of the appearances resulted from multiple comparisons of the posi-tion of the circumflex artery and mitral valve annulus in pairs offramesfrom the left ventricularand aortic root injections, matched for timing within the cardiac cycle. b) Case 4. Diastolicframe, selective retrograde left ventricular angiocardiogram in lateral projection. An elongated,faint, filling defect (solid black arrows) connects the mitral orifice with the single posteromedialpapillary muscle, thusgiving rise to an 'egg-timer' deformity. Above this (hollow black arrow) is asubaortic stenosis. Note the similarity of appearance of the pseudocoarctation in this Figure andin Fig. 3a. A hollow white arrow marks the aortic ductus diverticulum. A solid white arrowmarks the very small ventricular septal defect, and an open white arrow points to a ductusdiverticulum. AO = aorta, C= coarctation.



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anterior to, and well to the right of the pulmonary valve.There was a mild preductal coarctation associated withconsiderable aortic distortion and a short aortic ductusdiverticulum (Fig. 3a).

Open intracardiac operation was performed (P.B.D.)under cardiopulmonary bypass and moderate total bodyhypothermia (30°C).The findings were: double outlet right ventricle with

the aorta lying anteriorly and to the right; the ventricularseptal defect was large and some 5 cm from either semi-lunar valve; the anterior cusp of the tricuspid valve wasattached around the superior margins of the ventricularseptal defect; there was pronounced subaortic muscularobstruction, and a supravalvar mitral stenosing ring andunderlying this a parachute mitral valve. The subaorticmuscle was resected and after detaching the abnormaltricuspid insertion an intraventricular connexion be-tween the left ventricle and the aorta was created. Thetricuspid tissue was reattached to the right side of thepatch. The mitral valve was exposed by a transseptalright atrial incision. The supravalvar ring was excisedand the deformed mitral valve was removed and re-placed by a i9 mm Bjork-Shiley prosthesis.

After correction pressures were: left ventricle iI5/I5,aorta 85/44, right ventricle 70/8, left atrium (mean) 20,right atrium (mean) io mmHg.

Postoperatively the child needed intensive manage-ment for several days but then recovered well. She wasdischarged from hospital on the igth postoperative day.

Since operation she has made steady progress, withgood effort tolerance, no chest pain, and resumption ofnormal schooling.

Case 3A heart murmur was first noted in this boy at age 5 years.Over the next 5 years he grew slowly and developedexertional dyspnoea and tiredness and had a possiblesyncopal episode at age IO years. There was a familyhistory of two maternal relatives dying suddenly duringexertion at age I8 and 2I years, respectively. At 6 yearsof age, left ventricular and femoral artery puncture haddemonstrated no systolic gradient except during post-extrasystolic beats.On physical examination at IO years old, his pulses

were synchronous, regular, and jerky. The left ven-tricular impulse was forceful. A systolic thrill was pal-pable at the apex beat and suprasternal notch and therewas a palpable carotid thrill. A long ejection systolicmurmur was heard maximally at the lower left sternalborder with a third heart sound and mid-diastolicmurmur at the the apex.

Selective retrograde and antegrade right ventricularangiocardiograms indicated that the right ventricle andpulmonary arteries were normal. Pulmonary venousreturn was to an enlarged left atrium. There was nocrescentic shadow between the left atrium and ven-tricle, but the mitral valve showed the 'egg-timer' de-formity of parachute mitral valve (Fig. 2C). Though thesingle papillary muscle did arise from the posterior leftventricular wall, it was much thicker during systole thanin the other patients (Fig. 4a), when it divided the left

ventricle into two compartments with only a narrow,superior communication between them. In the frontalview there was a discrete subaortic diaphragm in theclassical position. There was moderately severe mitralregurgitation, but no coarctation or ventricular septaldefect.At open intracardiac operation in August I969 (M.I.I.),

before starting heart-lung bypass the left ventricularlaortic peak systolic pressure gradient was found to be8o mmHg, but was abolished by injection of intravenousphenylephrine. Digital exploration of the left atriumrevealed an important jet of mitral regurgitation. Theaortic valve was slightly thickened but otherwise normal.There was a stenotic diaphragm, barely admitting thetip of a little finger, I5 mm below the aortic annulus, anda parachute mitral valve, whose grossly hypertrophiedpapillary muscle divided the left ventricular cavity intotwo compartments. The two mitral cusps each had twovery thick portions, giving the impression of a quadri-cuspid valve.The diaphragm and mitral valve were excised, and the

latter replaced with a frame mounted autologous fascialata valve 22 mm in diameter. At the end of the pro-cedure there was no aortic valve gradient.The postoperative period was relatively uneventful.

Thereafter the child did well, apart from developing re-current episodes of nocturnal cough. Reinvestigationthree years after operation with angiocardiography(Fig. 4b, Table 3) indicated a moderate gradient acrossthe fascial valve which was competent. There was trivialresidual subaortic stenosis, and the response to post-extrasystolic beats of the left ventricular and aorticpressure was normal. There were no angiocardiographicfeatures of hypertrophic obstructive cardiomyopathy.

Case 4This girl was asymptomatic apart from slow weight gainin infancy.On physical examination at 6 years of age, she was

acyanotic, with normal peripheral pulses. There was asystolic thrill extending from the apex to both carotidarteries, and a diastolic apical thrill. The apical impulsewas single and thrusting. There was a long, roughsystolic murmur over most of the praecordium and aloud apical mid-diastolic murmur, of moderate lengthand without presystolic accentuation. The second heartsound was normal and there was no click or snap.

Angiocardiography was carried out with selective in-jection into the pulmonary artery and left ventricle.There was mild enlargement of the left atrium but noevidence of any supravalvar diaphragm. The mitralvalve showed the 'egg-timer' deformity and there was adiscrete subaortic diaphragm, and a small ventricularseptal defect. The aortic valve cusps were thickened andthere was a mild aortic coarctation with considerabletortuosity at the isthmus (Fig. 3b).

In view of the severity of the subaortic obstruction,open intracardiac operation was performed in Nov-ember I970 (P.B.D.). A fibrous subaortic diaphragm wasexcised and one fused commissure of a basically bi-cuspid aortic valve incised. The site of the ventricular



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a bFIG. 4 a) Case 3. Preoperative retrograde left ventricular angiocardiogram, lateral view,during systole. The grossly hypertrophied papillary muscle (PM) divides the left ventricularcavity into two compartments, separated by a narrow channel (between arrows) superior to thepapillary muscle. The catheter tip lies posterior to this channel, where the left ventricular pres-sure was raised. There is moderate mitral regurgitation. b) Case 3. Postoperative angiocardiogramunder the same conditions as Fig. 4a. After resection of the parachute mitral valve, there is nointraventricular obstruction. Arrows mark the stump of the papillary muscle. I, 2, 3 are thethree cusps of the fascia lata mitral valve replacement. AO =aorta, PM=papillary muscle.

septal defect was not apparent through the aortic rootand in view of its small size was not explored further.Pressure measurements suggested that the mitral obstruc-tion was not severe, and in view of the likely conse-quences of attempted relief of stenosis at this age, themitral valve was not explored.Two years after operation the child is symptomless.

Left ventricular hypertrophy is reduced clinically andelectrocardiographically. The physical signs of a smallventricular septal defect and moderate mitral stenosisremain.

Case 5This baby, weighing 2097 g, was product of a 38-weekbreech delivery and was admitted as an emergency at imonth of age with a history of dyspnoea and feedingdifficulties for a week.On physical examination she was acyanotic with a

respiratory rate of I20/min, but no hepatomegaly. Theupper limb pulses were bounding but the femoralpulses were weak. The flush pressures in the arms were

120 mmHg and in the legs 6o mmHg. Palpation of thepraecordium was normal. On auscultation the first andsecond heart sounds were normal apart from accentua-tion of pulmonary closure. There was a short unimpres-sive systolic and a loud mid-diastolic murmur at theapex.

Angiocardiography with selective retrograde injectiondemonstrated a hypertrophied left ventricle. The mitralvalve was competent, but in diastole the characteristic'egg-timer' appearance of parachute mitral valve wasseen (Fig. 2d). Furthermore, the anterior leaflet wastethered inferiorly so that it could not move normallyinto the left ventricular outflow tract in diastole. Insystole (Fig. 5) the single posteromedial papillary musclethickened considerably. The aorta was hypoplastic distalto the right innominate artery and there was a severecoarctation in the classical site.When the catheter was withdrawn from the left

ventricle it was noted that the aortic diastolic pressurehad fallen to I0 mmHg and a hand injection of contrastmedium into the aortic root showed severe aortic re-



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FIG. 5 Case 5. Systolic frame, lateral projection,of retrograde left ventricular angiocardiogram. Anarrow marks a severe coarctation. Note the bulbousappearance of the single papillary muscle (PM).AO = aorta, LC= left circumflex coronary artery,LV= left ventricle.

gurgitation. Some 8 hours later the child suffered asudden cardiac arrest and died.

This was the only patient in whom a definite diagnosisof parachute mitral valve was made before operation ordeath.

Necropsy demonstrated a modified parachute valve(Shone et al., I963; Davachi, Moller, and Edwards,197I). There were actually two papillary muscles of veryunequal size, both arising from the usual site of theposteromedial papillary muscle, with their origins abouti mm apart. The posterior mitral leaflet was almostabsent. The left ventricle was hypertrophied with whitishdiscoloration of the inner third of the myocardium, butnot endocardium. Histology of this abnormal myo-cardium showed disrupted myocardial fibres, many ofwhich were irregular in shape and contained cytoplasmicvacuoles. There was no supravalvar mitral ring. Theaortic valve was bicuspid and there was a 3 mm per-foration in one cusp. The aortic arch was hypoplasticand there was a severe preductal coarctation. The ductusarteriosus was barely patent and there was a patentforamen ovale.

Discussion

Parachute mitral valve and supravalvar mitral ringare at first sight different entities. They are dis-cussed together because they both cause congenitalmitral valve obstruction and frequently coexistwith one another and with a complex of otherabnormalities (suboartic stenosis, coarctation of theaorta, and to a lesser extent ventricular septal de-fect and bicuspid aortic valve) (Shone et al., I963).Three of the patients described above had parachutemitral valve, one had supravalvar mitral ring, andone had both. Operative or postmortem confirma-tion of the diagnosis was obtained in all patientsexcept Case 4. This patient, however, not only hadangiographic appearances typical of parachutemitral valve (v.i.) together with haemodynamicevidence of mitral obstruction, but also all four ofthe above associated lesions.An apical mid-diastolic murmur is common in

patients with ventricular septal defect, coarctationof the aorta, and subaortic stenosis, without therebeing organic mitral stenosis. Thus the clinicalrecognition of mitral valve obstruction in thepresence of these other lesions may not be easy.One of the patients (Case 3) had obvious signs of

mitral incompetence. In the remainder, whosemitral valves were competent, the apical mid-diastolic murmur was unduly prominent in theclinical picture as a whole. Obtaining a valid leftatrial pressure therefore became a first priority ininvestigation. In both patients with large ventricularseptal defects (Cases i and 2), the high values oftotalpulmonary resistance (Rp) and its ratio to systemicresistance (Rs) would have contraindicated surgeryhad not mitral obstruction been recognized. Valuesof pulmonary vascular resistance, though raised,were low enough to permit surgical correction of theimportant abnormalities with a moderate fall in rightventricular pressure as measured on the operatingtable after intracardiac correction. This was achievedwithout mitral valve replacement in the 2-year-oldpatient with supravalvar mitral ring, as has pre-viously been reported in one io-year-old patient(Lynch et al., I962). Since the obstruction due toparachute mitral valve cannot be adequately cor-rected without mitral valve replacement (Terzakiet al., I968), which may have disadvantages in smallchildren (Robinson and Young, I966), the pre-operative distinction between these two causes ofmitral obstruction is of considerable practicalimportance.

Carey, Sellers, and Shone (I964) stated that, 'it isunlikely, at present, that the definite diagnosis of aparachute mitral valve can be made by radiologicmeans.



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6So Macartney, Scott, Ionescu, and Deverall

Since then others (Terzaki et al., I968; Simon,Friedman, and Roberts, I969) have attempted todefine angiocardiographic appearances specific forparachute mitral valve. These have included thedemonstration of a single hypertrophied papillarymuscle, a cone-shaped appearance of the mitralvalve leaflets, and an abnormal systolic position ofthe mitral valve resulting in functional left ven-tricular outflow tract obstruction. If two papillarymuscles could be confidently identified angio-graphically when they were in fact present, identi-fication of a single papillary muscle would be a use-ful criterion for the diagnosis of parachute mitralvalve. However, in a review (F. J. Macartney,I973, unpublished data) of 50 consecutive, highquality left ventricular angiocardiograms per-formed in patients with congenital cardiac anoma-lies other than coarctation, subaortic stenosis, andleft ventricular hypoplasia, and with no clinical,angiocardiographic, or haemodynamic evidence ofmitral valve abnormalities, in I0 per cent no pap-illary muscles were identified, and in 36 per centonly one papillary muscle was seen. Two papillarymuscles were identified in 54 per cent. In this seriesit was noted that two papillary muscles were visual-ized in all ii patients with valvular aortic stenosis,since this resulted in papillary muscle hypertrophy.The incidence of identification of both papillarymuscles in patients without left ventricular outflowobstruction was only 4I per cent.An abnormal systolic position of the mitral valve

in apposition to the interventricular septum was notrecognized in any of our patients with parachutemitral valve. One patient (Case 3) did neverthelesshave severe functional subaortic stenosis as evi-denced by the response to postextrasystolic beatsand phenylephrine. Since phenylephrine abolishedthe left ventricular/aortic systolic pressure gradient,the obstruction produced by his discrete subaorticdiaphragm cannot have been significant. Resection ofthe parachute mitral valve resulted in disappearanceof functional subaortic stenosis. Review of his pre-and postoperative left ventricular angiocardiograms(Fig. 4) and operative findings suggest that it wasthe papillary muscle and not the mitral leafletsthat caused functional subaortic stenosis, by dividingthe left ventricular cavity into two portions duringsystole. This obstruction would be abolished byinterventions such as phenylephrine, which in-crease left ventricular volume, thus allowing moreroom for the hypertrophied papillary muscle.Furthermore, the posterior site oforigin ofthe singlepapillary muscle which was present in all 4 patientswould be expected to prevent rather than causeapposition of the anterior leaflets of the mitral valveto the septum during systole.

The normal mitral valve has two leaflets in ananterior and posterior position. The papillarymuscles are anterolateral and posteromedial, andchordae tendineae from each papillary muscleinsert into both mitral cusps. Thus when the mitralvalve opens there is a wide central orifice. If only asingle papillary muscle is present and the chordaeare somewhat short, the anterior and posteriorleaflets are held together during diastole, so thatblood must egress through the interchordal spaces(Shone et al., I963).

If the single papillary muscle lies in the normalposition of the posteromedial papillary muscle, aswas demonstrated in these 4 patients, the normaldiastolic anterior movement of the anterior leafletwill be restricted and there may be loss of the usualappearance of swinging of the anterior leaflet on theleft and non-coronary aortic sinuses, wherebymitral-aortic continuity is normally diagnosed(Hallerman et al., I970). This was evident in Case 5and present to a lesser extent in Case 4. In Case 2restricted movement of the anterior mitral leafletwas obvious, but mitral/aortic continuity was in anycase not present as both great arteries originatedfrom the right ventricle.

Angiocardiographic diagnosis of parachute mitralvalve is not made easier by the fact that its twomajor components, the valve leaflets and papillarymuscle, are best visualized at different times in thecardiac cycle. The leaflets are best observed duringventricular diastole when unopacified blood istraversing the mitral orifice, whereas papillarymuscles are easier to identify during systole whenthey are shorter and thicker. Nevertheless we be-lieve that parachute mitral valve can be identifiedwith confidence by the subtle but unmistakableappearance of an 'egg-timer' shaped filling defectduring ventricular diastole observed on the lateralangiocardiogram. The posterosuperior portion ofthe egg-timer is formed by the coned mitral leafletsand chordae tendineae, and the anteroinferior por-tion by the single papillary muscle (Fig. 2a). Insystole the papillary muscle alone is visualized, butthis is not a specific finding, for reasons alreadystated. Since the papillary muscle has to be vis-ualized in diastole, it is clear that it will only be seenon the highest quality angiocardiograms.The other abnormalities of mitral valve structure

noted in some, but not all, of these patients, wereirregularity of the margin of the anterior mitralleaflet, together with a more than usually curvedfree edge, probably due to the restricting influenceof the tethering chordae tendineae.For the reasons already stated parachute mitral

valve must, by its very nature, result in some mitralvalve obstruction. In the one patient in whom the



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Parachute mitral valve complex 65i

valve was predominantly incompetent, there wasalso pronounced cusp thickening and deformity.Though mitral incompetence has been described inprevious reports (Terzaki et al., I968; Glancy et al.,I97I), the majority have had pure stenosis of thevalve.The association of parachute mitral valve with

origin of both great vessels from the right ventriclehas been previously noted in 3 patients (Davachiet al., I97I). To our knowledge, Case 2 in this seriesis the first to have undergone successful surgicalcorrection, and is of further particular interestsince, though the ventricular septal defect was some

5 cm below the pulmonary valve, left ventricularblood was preferentially directed into the pul-monary artery rather than the aorta. This observa-tion conflicts with the classic view of the haemo-dynamics of origin of both great vessels from theright ventricle, which is that when the ventricularseptal defect is subcristal, the crista deflects leftventricular blood preferentially into the aorta(Neufeld et al., I962). The unusual streaming ofblood in this patient may have been due to theabnormal attachment of tricuspid valvar tissue tothe superior rim of the ventricular septal defect.

Preoperative diagnosis of supravalvar mitral ringhas only been reported in one patient (Lynch et al.,I962) and never angiocardiographically. Though itwas specifically searched for preoperatively in bothpatients with this abnormality, it was diagnosedin neither. Transient regurgitation into the leftatrium not infrequently demonstrates well a leftatrial membrane in cor triatriatum (Miller et al.,I964), but regurgitation did not occur in thesepatients. Retrospectively it was possible to identifya thin crescentic defect between the left atrium andleft ventricle (Fig. I) during pulmonary venous

return in both Case i and 2. This appearance hasnot been observed by us nor reported by others incongenital mitral valve stenosis, so it was pre-

sumably due to the supraventricular diaphragm.However the mitral leaflets could not be identifiedas separate from this structure. A supravalvar ringis so close to the mitral valve leaflets, and mitralleaflet abnormalities coexist so commonly withsupravalvar ring, that exact preoperative dis-tinction between congenital supravalvar and val-var mitral stenosis is inevitably difficult. Our cur-

rent policy in patients such as Case 4 would be to

explore the left atrium even if mitral obstruction ismild and no supravalvar diaphragm has beenvisualized angiographically, in the hope of findingan easily resectable supravalvar ring. The post-operative course in the 4 patients operated on was

relatively uneventful. This re-emphasizes the possi-bilities of complex intracardiac corrections for con-

genital heart disease, provided that the significanthaemodynamic lesions are recognized preoperativelyand corrected at surgery.

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Neufeld, H. N., Lucas, R. V., Jr., Lester, R. G., Adams, P.,Jr., Anderson, R. C., and Edwards, J. E. (I962). Origin ofboth great vessels from the right ventricle without pul-monary stenosis. British HeartJournal, 24, 393.

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Shone, J. D., Sellers, R. D., Anderson, R. C., Adams, P., Jr., Terzaki, A. K., Leachman, R. D., Ali, M. K., Hailman, G. L.,Lillehei, C. W., and Edwards, J. E. (I963). The develop- and Cooley, D. A. (I968). Successful surgical treatmentmental complex of 'parachute mitral valve', supravalvu- for 'parachute mitral valve' complex: report of 2 cases.lar ring of left atrium, subaortic stenosis, and coarctation J7ournal of Thoracic and Cardiovascular Surgery, 56, i.of aorta. American_Journal of Cardiology, 11, 7I4.

Simon, A. L., Friedman, W. F., and Roberts, W. C. (I969).The angiographic features of a case of parachute mitral Requests for reprints to Dr. F. J. Macartney, Killing-valve. American HeartJournal, 77, 809. beck Hospital, York Road, Leeds LS14 6UQ.



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