Congenital mitral stenosis

Congenital Mitral Stenosis* R ON .A I .D L . VAN DER HORST, M.D . and ALOIS

R.

HASTREITER, M .D .

Chicago, Illinois

CONGENITAL mitral stenosis is a rare cardiac lesion . Reports thus far available consist of individual cases or of relatively small series of patients, with the exception of Ferencz and associates' comprehensive review' in 1954 . In the light of recent advances in diagnostic and surgical technics, various aspects of this lesion, such as the natural history, hemodynamie findings and operative results, deserve re-evaluation . The present study consists of an analysis of these features in 23 children with congenital mitral stenosis, and a review of 99 selected cases from the literature . The cases are classified into various anatomic complexes according to the associated lesions (Table I) .

months from the onset of symptoms, and few lived beyond two years without surgery . The survival period was even shorter in children with associated cardiac lesions, particularly those with aortic stenosis. Congestive heart failure was present in virtually all patients studied and produced the most prominent and early symptoms . In half of our cases physical growth was retarded, and in some this was an outstanding feature . Respiratory infections, including pneumonia, complicated the clinical picture and course in about half of the cases. Cyanosis occurred usually as a terminal complication, and only 2 patients with an associated patent ductus arteriosus had differential cyanosis . Other rare symptoms included syncope, hemoptysis and aphonia attributed to compression of the recurrent laryngeal nerve by the dilated left atrium. Cardiovascular examination varied according to the associated lesions . The peripheral pulses were abnormal in cases with coarctation of the aorta and in some with a patent ductus arteriosus or aortic stenosis . Clinical evidence of Cardiomegaly was detected in virtually all cases . A precordial bulge was found in most . The intensity of both the first and second heart sounds was often increased . The second heart sound was usually narrowly split and fixed with respiration . A mitral opening snap was heard in only 3 of our cases and in 5 from the literature ; most of these children had isolated congenital mitral stenosis . A heart murmur was present in all our patients ; 14 had a long apical middiastolic rumbling murmur, and in 6 the murmur had a rough crescendo presystolic component . One child had an early diastolic aortic insufficiency murmur . A number of patients had systolic murmurs, and these were attributed to the associated cardiovascular defects (i .e ., aortic stenosis, patent ductus arteriosus, or ventricular

CLINICAL MATERIAL

Our 23 cases of congenital mitral stenosis were collected from 1953 to 1965t ; 11 were male and 12 female . Nine underwent surgery. Seventeen died and postmortem examination was available in all . The age range was from 3 days to 17 years . The clinical, hemodynamic and pathologic findings are shown in Tables ii through iv . OBSERVATIONS CLINICAL FEATURES

A heart murmur was discovered before 6 months of age in all but 3 patients, and in the neonatal period in 12 . The onset of symptoms occurred before 1 month of age in a third and before 1 year of age in three-fourths of the cases . Symptoms were observed earlier in children with additional cardiovascular defects. Of the 17 deaths in this series, 10 occurred before 6 months of age and only I beyond 3 years. Analysis of the literature indicates that a fifth of the children died in the neonatal period, half within one year of birth, and that only a fifth survived to 3 years of age . Half of the patients died within six t A group of patients previously reported is included in this series 2 (Cases 10, 16-20) .

" From the University of Illinois Research and Educational Hospitals, Cook County Children's Hospital and the Hektoen Institute for Medical Research, Chicago, Ill . This work was supported in part by Grants NIH 08956-03 and CHA N-66-40 . VOLUME 20, DECEMBER

1967

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774

van der Horst and Hastreiter 7 ABLE I Classification of Congenital Mitral Stenosis

Group

-No . of Cases This Series Others Total -Reference -

Anatomic Complex

I

Isolated congenital mitralstenosis

n

Congenital nitral stenosis associated with other left-sided obstructive lesions, and/or patent ductus arteriosus A . Obstructive lesions without patent ductus arteriosus 1 . Coarctation of aorta 2 . Aortic stenosis 3 . Aortic stenosis and coarctaton of aorta B . Patent ductus arteriosus only C . Obstructive lesions with patent ductus arteriosus 1 . Coarctation of aorta 2 . Aortic stenosis 3 . Aortic stenosis and coarctation of aorta

In

Congenital mttral stenosis associated with a ventricular septal defect Total

7

43

50

1, 4-6, 9-19, 23, 26-28

2 0 1 3

7 8 0 15

9 8 1 18

1, 3, 7, 16, 21, 24, 26 1, 6, 17, 25

2 3 3

5 8 3

2

10

12

23

99

122

1, 9, 10, 15, 17, 20, 24

7 1, 21, 24 11 1, 10, 28 6 1 1, 15, 19, 20, 24, 29

TABLE U Clinical Findings in the Present Series of 23 Patients with Congenital Mitral Stenosis

Group* r

Case & Sex I F 2 F 3 F 5 M 6 F 7 M

n A (1) (3) B C (t) (2) (3)

Age Age Murmur Onset of SympDereeled tuna Birth 6 yr. 6 too. 2 yr. 3 too.

8 M 9 F

6 wk . 2 wk . 10 M 2 too. I I F Birth 12 M Birth 13 F 14 F 3 wk . 15 F Birth 16 M 2 days 17 M .5 days 19 M 20 days 19 M 10 days 20 F 3 days 21 M 2t/ s yr . 22 F . .. 23 M Birth

nt

5 .o . 6 yr. 6 me. l yr. 3 too. 6 wk . 10 days 2 too . Birth Bath

Clinical Finding Duration Age of Symptoms at to Death Death

Growth RadiofogicFindingsReLeft Pulm . tardaHeart Atria[ Vascular} Studies GHF tion Pneum . Cyan . Suet Friars. Markings C A S P

Alive Alive 6 yr. (DS) 6 yr . 2 yr. 3 yr . 12 mo . (DS) 15 ma. Alive Alive

+ + + + -

+ + +

1 too. 4 wk. 5 too . (DS) 5 too . 9 wk.

+ + + + + + + + + + + + + + + +

+ + +

2 too. 6 wk. 7 too . 5 too . 9 wk. 2 yr . 3 wk . 15 ton. (DS) 16 ton. 5 yr. Alive ... Birds 15 days 17 days Birth B days B days 20 days 10 days I too . 7 days 10 days 17 day, Birth 3 days 3 days 2t/s yr. Alive Alive Infancy 20 me . (DS) 32 too . 3 mn . Birth 3 me.

+ + +

+ + ++

+++ +++ ++ ++

+LAA + +LAA

+ + +++

+LAA

+ N N

+ + 0

++ LAA .. . + D + +

+

++

+

+ + + +

+ +

+ +

+++

+++

+ + + + + + + + +

+ + - + + + + + + + + + + - -

- + - + - +

+++

+

+

+ + + +

+ N

0 LAA

0 +

+

++ ++

+ +

++ ++

+++ ++

0 0

+ +

+ + - -

t

+ + - +

++++

+

++

0

+

++ + ++

0 0

+ + +++

+LAA

T - + - - - + + + - +

+ + + + + + + + +

+ + - +

+ + r

+ + +

+ + -

+ + +

See Tables fm classification . t Degree of enlargement . CHF - congestive heart failure ; Pneum. - pneumonia ; Cyan. . cyanosis ; Enlarg . enlargement ; Pulm . - pulmonary ; C = cardiac catheterization ; A = angiocardiography ; S = surgery ; P = postmortem examination ; IAA- = prominent left alrial appendage ; N = normal ; DS - death related m surgery; D - differential cyanosis . •

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Congenital Mitral Stenosis TABLE Ill Cardiac Catheterization Findings in the Present Series of Patients with Congenital Mitral Stenosis

Go-,*

C :ua No.

1

1

2 3

n A (3) B

C (1)

Qst (l ../mivs M.')

Q,/Q,

2 yr.

3 .9

1 :1

5

17 yr. 21 mo. 6 qr.

4 .7

1 :1

2 11

0 .5

Agc

4 5

2 yr . 6 mo .

6

2 yr .

4 2 .0 4 .0

1 1

15 2

RV

0 .3

98

m = 1

40/0

35 ./10

0 .1

95

= 1 = 4 m = 5

36/2 59,14 89/5

40/18 a = 18 m m = 19 a 89/48 m = 19 m a

= 13 m = 3 m = 4

52/13 96/2 50/7

±0 .5 0 .1

7

2 yr .

4 .3

1 :1

5 mo .

3 .0

1 :1

WNL

1 :1

14

0 .6

8

±0 .4

4 too .

2 .5

13

17 mn .

±2 .8

14

11 on .

2 .7

1 :1

- Pressures (mm . Ilg)

B RA

10 11

2

-

Arterial O : Sat. 1%)

Rpt Rp/Rs (units)

96 98

I'CW

96/44 , = 42/24 a = = 45/12 m = 24/12

LA

0 .1

97

m = 5

99

in - 4

92

m = 4

80/3

Asc. An . m = 3 = 100 Des,. Ao. = 75 93 m = 3

7(3/2

80/54 a = 30 29 68/48 m = 37,

62/3

64/26

L3'

= 18 13 19 25 22 27

-

-Arrcry

80/50

= = = =

26 30 26 15

WNL

l0

45/5

PA

95/60 93/58

95/65 110/10

110/70 90/56 163/54 80/50 66/46

84/53 m=13

15 mo. (2)

(3) n1

2 .7

1 :1

15 8 f5 14 8 5 11

0 .4

IS 16 18 19 21

2 wk . 3 wk . 2 wk. 2 yr.

3 .0 2,7

1 :1 1 :1 1 :1 2 .8 :1

22

1 mo.

3 .0

1 .7 :1

89

m = 8

0 .3

97

m = I

±0 .3 0 .7 0 .4 0 .2

83 98 91 99

m m m in

90

m = 5

= = = -

6 7 6 2

80/5 86/11 45/6 108/10 90,/10 u '/ 9 103/5

82/37 a = 25 m = 15 77/33

in = 24 a = 36

170/7 97/44 m = 24 m = 24 m = 14 135/28 56/33 126,'20 82/45 in = 28 100/55 a = 30 in 20

140/75 1 95/70 110/65 70/40 70,150 70/50 110/ 60 105/70

* Sec Table I for classification. t The Fick principle was used for calculation of blood flows . 1 mm . Hg I unit 80 dynes s ec . c m . -r. ./min L ../M . - systemic blood flow ; Qp - pulmonic blood flow ; Rp = pulmonary vascular resistance ; Sat . = saturation ; RA = right atrium ; RV = Q right ventricle ; PA = pulmonary artery ; POW = pulmonary capillary wedge ; LA = left atrium ; LV = left ventricle ; Artery = sysmtnic atwi, in mean ; a = a wore'

septal defect) . A diastolic apical murmur was described in only 29 patients from the literature ; in 9, there was a presystolic accentuation of the murmur . PHONOCARDIOGRAPHIC FINDINGS

Heart sound recordings, obtained in 6 children of this series (3 with isolated mitral stenosis), revealed high amplitude of the first and second heart sounds, narrow splitting of the second sound, and a low frequency diastolic murmur in all cases . Presystolic accentuation of the murmur was present in 4 cases and a mitral opening snap in 2 (Fig . 1) . The Q-1 interval was prolonged in most instances . Both patients with an opening snap were older children with isolated mitral stenosis, and both had a presystolic murmur . ELECTROCARDIOGRAPHIC ASPECTS

Data were obtained from 22 of our cases (Fig. 2) and from 19 electrocardiograms pubVOLUME

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1967

FIG . 1 . Case 1 . Phonocardiogram of a patient with isolated congenital mitral stenosis . MLSB = mid left sternal border ; S, = second sound ; S, = first sound ; DM = diastolic tnnrlro r ; PSM = prcsystolic nmrmur ; OS = opening snap .



776

van der Horst and Hastreiter TABLE IV Pathologic Findings in the Present Series of Congenital Mitral Stenosis

Group*

Case

Age at Death

3 4

6 yr. 3 yr.

5

15 mo .

8

2 ran .

Ilypoplastic, with abnormal insertion

N

9

1 mo.

Hypoplastic ; small posterior leaflet

N

10

7 mo .

Dypoplastic ; fairly well formed

11

5 mo.

Bicuspid nodular, stenosed N

t

o A (1)

(3) B

12 C (1)

14

(2)

16

(3)

Mitral Valve Hypoplastic ; fairly wed turned Annular obstruction ; slightly duckened Nodular thickening ; short } thick chordae

Markedly deformed, with nodular thickenings ; barely patent 2 ato. Hypoplastic ; fairly well formed 16 me. Hypoplastic ; thick and diffusely deformed 17 days Hypoplastic ; markedly thickened

17

8 days Mild hypnplasia + thickening

18

1 mu.

19

Thickened ; short chordae

17 days Hypoplastic ; slightly thickened

20

3 days Mild hypoplasia ; thickened

22

2 yr .

23

3 mo .

Severely deformed and thickened : posterior commiasure fused Markedly deformed and thickened ; only a medal cusp identified

Aortic Valve

(iioarmauon of Aorta

PDA (size)

FIFE ((site)

Foramen ovule

Other

N

N

LA & LV

N

PFO l'redurtal, long Pre-duetal Pre- & postductal

...

Mild LA

Pro

Mild LA

Fossa ovalis defect

Mild LA

Pro

Large

La

Large Large

LV LV

Pro

Bicuspid, stenosed

Mod.

LA & LV

PFD

Thickened & nodular, stenosed Thickened & steamed Thickened & nodular, stermed Thickened & stenosed

Mod,

LA & L V

Small

Mild LA

Pro

Large

LV

PFO

Pre- and Mod . post-duetal

LV

Pro

N

Pre-ducat

Mild LA

...

Large VSD

Mild LA

PFO

Large VSD

Bicuspid Bicuspid

Post-duetal

Mild hypoplasia

+See Tablet for classification . PDA = patent ductmartetiosus ; FIFE = endocardial fibrnelastosis ; N - normal ; Pro cars ; Mod . = moderate ; IVC = inferior vena cava ; VSD = ventricular septal defect .

lished by others . The mean frontal QRS axis lay between +90 and +150 ° in three-fourths of the cases ; it was less than 90 ° in 5 patients who were older children with isolated congenital mitral stenosis . With two exceptions, the frontal mean P wave axis ranged from 0 to 60 ° , and in three-fourths of the cases it lay between 30 and 60° . The mean T wave axis in the frontal plane had a considerable scatter, but, with 4 exceptions, it lay between 0 and 120 ° . First degree atrioventricular block was present in 7 of our patients and in 2 from the literature, but almost all were receiving digitalis . Electrocardiographic criteria for definite or borderline right atrial overload were present in almost 90 per cent of the tracings of this series and the literature . The total incidence of left atrial hypertrophy was also close to 90 per cent . Seventeen of our patients had definite, and 2 borderline, criteria for right ventricular overload . In the literature, right ventricular overload was always present. Left ventricular overload was a rare finding in isolated congenital mitral stenosis ; it occurred, however, in virtu-

=

Persistent LSVC Aortic-LV fistula

Straddling PVC

patent foramen uvale ; LSVC = left superior vena

ally all cases with associated aortic stenosis and in almost all cases with an associated ventricular septal defect . The QRS complexes in lead V 1 were most often of the RS or Rs variety and less frequently had a qR, qRs or rs configuration . In lead V 6, they were usually of RS type, but a Q wave was present in 16 of the 41 cases . Five of the 18 patients with isolated congenital mitral stenosis had a Q wave in lead V6 . A positive T wave in lead V3 (a criterion for right ventricular overload in children) occurred in a third, and an isodiphasic T wave in an additional 20 per cent of the cases with isolated congenital mitral stenosis . Sixty-five per cent of all patients had a positive or isodiphasic T wave in lead V 3. Inverted T waves in the left precordium were present in almost all patients with associated aortic stenosis but occurred rarely in other instances . VECTORCARDIOGRAPHIC FEATURES

References to vectorcardiographic studies in congenital mitral stenosis are few (Fig . 2) . The orientation of the QRS loop in the horizontal THE AMERICAN JOURNAL OF CARDIOLOGY

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Congenital Mitral Stenosis plane is usually clockwise or 8-shaped with the returning limb anterior to the E point, indicating right ventricular overload . In other cases, the 8-shaped loop suggests combined ventricular overload . Finally, children with milder forms of mitral stenosis may show a normal counterclockwise loop in the horizontal plane . The latter occurred in 2 of our patients (Cases I and 21) . RADIOLOGIC ASPECTS

Almost all our patients had considerable cardiac enlargement on x-ray examination . The shape of the heart in older children was similar to that described for adults with acquired mitral stenosis, with a straight left border . This typical cardiac configuration was not observed in infancy . A third of our patients showed a prominent left atrial appendage in the anteroposterior view (Fig . 3), and almost all had radiologic evidence of left atrial enlargement either in the plain films or with barium swallow . This was not diagnosed, however, in 5 of our patients x-rayed in the neonatal period . Radiologic findings of passive congestion of the lungs were present in all patients . Some children showed radiologic findings typical of severe pulmonary venous obstruction, including Kerley's lines . ANGIOCARDIOCRAPHIC FEATURES

Conventional biplane or cineangiocardiographic studies were performed in 19 of our 23 patients, including all 7 with isolated congenital mitral stenosis (Fig . 4 and 5) . They revealed dilatation of the right atrium, right ventricle and pulmonary artery in all instances . The pulmonary circulation was delayed, and the left atriurn was, as a rule, moderately large . In early infancy, however, it was sometimes small . Occasionally, the thickened left atrial wall could be well defined, and cineangiocardiography showed powerful atrial contractions which simulated ventricular motility. The mitral valve annulus was usually severely narrowed, and the valve had often a funnel-shaped appearance . Its size did not change appreciably during the cardiac cycle . In uncomplicated cases, the left ventricular chamber was normal or smaller than normal in size, but in cases with associated lesions it was sometimes enlarged . The aorta tended to be moderately small . HEMODYNAMIC FINDINGS

The cardiac catheterization findings of our patients are shown in Table in . Additional VOLUME

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B Fin . 2 . Etadrncmdiogram and ueclorcardiegram in patients with congenital mitral stenosis . A. Case 14 . Mitral stenosis plus coarctation of aorta and patent ductus arteriosus_ Right ventricular hypertrophy is present . B, Case 22 . Mitral stenosis and ventricular septaI defaK . Combined ventricular hypertrophy is present .

information was obtained from selected cases reported in the literature . Group I.

Isolated congenital mitral stenosis (7 of

The ages ranged from 2 months to 18 years . The mean left atrial or pulmonary arteriolar wedge pressure varied from 10 to 36 mm . Hg . Since left ventricular catheterization was performed in only a few patients, information concerning the gradient across the mitral valve was inadequate . When available, the left ventricular end-diastolour cases and 19 from the literature) :

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van der Horst and Hastreiter

B Fin . 3 .

Chest roentgevogranac of patients with congenital initral stenosis . A, Case 22. B, Case 5 .

he pressure tended to be high-normal or slightly elevated, reflecting perhaps a reduction of left ventricular compliance due to endocardial fibroelastosis . All but 4 patients had pulmonary hypertension, and in only 2 was it mild . In half of the remaining children pulmonary hypertension was moderate, and in the other half it was severe (more than two-thirds of the systemic pressure) . An elevated pulmonary vascular resistance occurred in 57 per cent of the patients, i .e ., in 2 of 10 patients under 3 years of age (20°%c), and in 9 of 12 over 3 years (75%) . Group

II.

Congenital mitral stenosis associated

with other left-sided obstructive lesions (aortic stenosis, coarctation of the aorta and

a

patent ductus arteriosus,

A.

Obstructive lesions without a patent ductus

arteriosus (1 of our cases, and 5 from the literature) :

The ages ranged from 5 months to 3 years, except for one 9 year old child . The mean left atrial pressure, available in 3 cases, Ineasured 15, 28 and 30 mm . Hg . The pulmonary artery pressures varied from normal (3 cases) to severely elevated . Two older children (3 and 9 years old) had a severely elevated pulmonary arteriolar resistance . Data concerning left ventricular pressures were inadequate . In only 1 case was the systolic pressure gradient across the aortic coarctation determined, measuring 30 nun. Hg . B.

Patent ductus arteriosus only (2 of our cases,

The ages ranged from 5 months to 7 years . The left atrial pressures were severely elevated in our cases : 29 and 32 nun . Hg . There was inadequate information concerning the left ventricular pressures . All patients had moderate to severe pulmonary hypertension, and 6 had a definite increase in pulmonary vascular resistance . The left to right shunt was small or completely absent, and 4 children had a right to left shunt at the ductal level .

o both)

and 8 from the literature) :

C.

Obstructive lesions with a patent ductus

arteriosus (6 of our cases, and 2 from the literature) :

gin a diagram in congeni al snit at Hot projection, left atrial injection .

Three of the 4 children with aortic stenosis were less than 1 month old (age range, 2 weeks to 2 years) ; in contrast, the 4 patients without aortic stenosis varied in age from 15 months to 8 years . The mean left atrial pressure, available in 5 instances, ranged from 13 to 28 turn . Hg, but was higher than 24 mm . Hg in 4 cases . In 2 children in whom left ventricular end-diastolic THE AMERICAN JOURNAL OF CARDIOLOGY

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Congenital Mitral Stenosis

A

Case 14 . Angiocardiogam in congenital mitral stenosis . .Anteroposterior right a trial injection . Fin . 5 .

pressures were available, these were also high (20 and 28 min . Hg) . One of our patients (Case 16, 2 weeks old) had a normal left ventricular end-diastolic pressure and only mild pulmonary hypertension ; a left atrial pressure was not obtained . The left to right shunt was small in all cases, and in 2 instances there was a right to left shunt through the patent ductus . In all but 2 children the pulmonary artery pressures approached systemic levels, and the pulmonary vascular resistance was elevated . The 2 exceptions had mild and moderate pulmonary hypertension, respectively . The aortic-left ventricular pressure gradient, determined in 3 cases, measured 16, 65 and 100 rum . Hg, respectively . The systolic pressure gradient across the aortic coarctation was obtained in only 1 case and was 60 nun . Hg. Group III . Congenital mitral stenosis associated with a ventricular septal defect (1 of our cases, and .5 from the literature) : The ages varied from 11

months to 19 years, but only 2 children were below 5 years of age . The mean left atrial or pulmonary arteriolar wedge pressures ranged from 15 to 23 nun . Hg . The pulmonary-tosystemic blood flow ratio varied from 1 .5 to 2 .0, and in a few cases there was a small right to left shunt . All patients had severe pulmonary hypertension with increased pulmonary vascular resistance . SURGICAL TREATMENT AND RESULTS

A total of 12 surgical procedures were performed in 9 children of the present series, inVOLUME

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(A)

and lateral

IB)

projections,

eluding 7 mitral valvotomies . In Case 2 the valvotoniy was performed twice, at 10 and 17 years of age ; there is mild residual mitral insufficiency . The other 2 survivors of mitral valve surgery (Cases 6 and 15) had a closed valvotomy at 3 years of age, and a valvotomy under direct vision at 8 years of age, respectively . The latter had had surgery for coarctation of the aorta and patent ductus arteriosus two years earlier . Patients 3 and 5 died during surgery for mitral valvotomy, and in Case 22 complete heart block developed and the patient died 14 hours following the valvotomy and repair of a ventricular septal defect . In Case 14 a successful resection of a coarctation of the aorta and ligation of the patent ductus arteriosus was performed at 2 months of age, but the patient died at 16 months of age during an attempt to replace the mitral valve with a Starr-Edwards valve . One infant died during an aortic vatvotoiuy at 7 months of age (Case 10), while another child is well 6 months after division of t he patent ductus arteriosus at 21 2 years of age (Case 21) . The total mortality in this series is 50 per cent for mitral valvotousy, and 25 per cent for surgery on other structures . Thirty-two of the reported operative procedures on the mitral valve in congenital stenosis were analyzed, These consisted of a mitral valvotomy in 31 patients (under direct vision in 4), and replacement by a modified Starr-Edwards valve in 1 . 'The total mortality was 63 per cent, About half of these (10/19) died within 72 hours of surgery . For those surviving,



780

van der Horst and Hastreiter

the follow-up period extended from seven months to five years . In cases with isolated congenital mitral stenosis, the surgical mortality was also in the range of 60 per cent . In isolated series, however, it was significantly lower, e.g., 40 per cent in Starkey's group . 17 Nine children were under 3 years of age at the time of mitral valvotomy . Only 1, a 3 month old infant, survived the procedure. Of the 4 patients in whom an open valvotomy was performed, only I survived . The infant who had a prosthetic valve replacement was 10 months old at surgery and was reported to be alive two and a half months later' 7 ; pressure determinations following replacement revealed no gradient across the prosthetic valve. Thirteen patients with congenital mitral stenosis had surgery to structures other than the mitral valve, mostly the ductus arteriosus and coarctation of the aorta . Of the 4 survivors, 3 had had a repair of the ventricular septa) defect . There are very few postoperative hemodynamic studies on record . Starkey's 2 patients17 showed a reduction in pulmonary arteriolar wedge pressure, and 1 of these a decline in pulmonary artery pressure. One patient of this series (Case 2) required a repeat valvotomy since the initial procedure failed to lower the pressure gradient between the left atrium and ventricle. Another patient (Case 6), operated on elsewhere for a relatively mild stenosis, had a 5 mm . Hg drop in the gradient . PATHOLOGIC FINDINGS

The present review includes only those cases of congenital mitral stenosis in which the left ventricle is able to handle adequately the systemic cardiac output . The left ventricular size ranges from larger to slightly smaller than nortrial . The "hypoplastic left heart syndrome," in which the left ventricle is nonfunctional and largely bypassed, is excluded . Premature closure of the foramen ovale, a complex which often includes mitral stenosis, is not included because of the short life span of the infants affected . Cases with truncoconal anomalies (transposition complexes, double outlet right ventricle and tetralogy of Fallot) and other miscellaneous conditions rarely reported to occur with mitral stenosis (pulmonary valvular stenosis, tricuspid stenosis, Ebstein's anomaly of the tricuspid valve, double aortic arch, etc .) are not analyzed . We have also excluded cases of "parachute mitral valve," anomalous insertion of chordae or

fibrous bands below the mitral valve, and Hurler's syndrome . Associated Congenital Lesions : Congenital mitral stenosis occurs as an isolated lesion or as part of an anatomic complex which includes other left-sided obstructive lesions (coarctation of the aorta and aortic stenosis) or shunting lesions (patent ductus arteriosus and ventricular septal defect (Table I) . The cases of congenital mitral stenosis and ventricular septal defect have no further accompanying lesions . Aside from the anomalies which form the basis for the complexes described above, cardiovascular defects are quite rare . Only 1 patient in this series (and none in the literature) had a secundum atrial septal defect ; this may represent additional proof against the congenital origin of Lutembacher's syndrome . Other anomalies were biscuspid aortic valves-2 in this series and 3 in the literature'" ; origin of both coronary arteries from the left sinus of Valsalva-1 in this series and 1 in the literature" ; a persistent left superior vena cava-1 in this series and 3 in the literature" • 20,25 ; and a fistula from the sinus of Valsalva to the left ventricle (Case 16) . The significance of a patent ductus arteriosus in patients below 3 months of age included in this study could not be evaluated properly . However, in each complex with congenital mitral stenosis and a patent ductus arteriosus there were older children in whom patency of the ductus arteriosus must be regarded as significant . The type of coarctation of the aorta (pre- or post-ductal) in the present series is shown in Table iv . In the cases collected from the literature, this was often difficult to evaluate . It is probable that in some of these (particularly in infants) a so-called transitional form of coarctation was present ." The aortic stenosis associated with congenital mitral stenosis was usually valvular in type (rarely subvalvular fibrous) . In younger patients, the aortic valve cusps were often poorly differentiated . Endocardial fibroelastosis of the left ventricle occurred in most cases of congenital mitral stenosis but was even more common and more severe with associated aortic stenosis . Left Ventricle : Grouping all complexes of congenital mitral stenosis together, the left ventricle ranged in size from large to somewhat smaller than normal . It was reduced in size in 6 cases of this series ; 4 of these children had isolated mitral stenosis . In the presence of aortic stenosis, the left ventricular cavity was usually larger than normal . This was not as THE AMERICAN JOURNAL OF CARDIOLOGY



Congenital Mitral Stenosis

781

B Fm . 6 .

Pathologic spesimrtn of Case 5 (AW and Case 8 (B) with congenital mitral stenosis .

apparent in cases with a ventricular septal defect, patent ductus arteriosus, or coarctation (if the aorta . The left ventricular wall was nortrial or somewhat thickened in isolated mitral stenosis, but it was always hypertrophied in cases with associated aortic stenosis, coarctation of the aorta, or patent ductus arteriosus . Left Atrium : The left atrial cavity was considerably enlarged as a rule in children with congenital mitral stenosis . In some cases, however, it was thought to be smaller than normal . A small left atrium was encountered in younger infants, including the patient with an atrial septal defect (Case 9) . In some of these, the increased pulmonary vascular resistance may have been an instrumental factor in preventing left atrial enlargement . Isolated reports described a gigantic left atriums The left atria) wall was always thickened and almost always the site of severe fihroelastosis . Right Heart : All our cases had a hypertrophied right ventricle and most cases right ventricular dilatation . The right atrium was almost always dilated and thickened . A patent foramen ovale was present in the majority, including 2 children above 1 year of age . Mitral Valve : The degree of narrowing of the mitral valve orifice varied but was usually VOLUME 20, DECEMBER 1967

severe . 'The mitral valve annulus ranged from normal to markedly reduced in size . The leaflets varied in appearance from slightly thickened to extremely thickened and nodular . The commissures were fused to a variable degree . In extreme cases, the valve was markedly deformed, the commissures and leaflets were not recognizable, the entire structure of the valve was distorted, and its contour varied with increasing severity from funnel-shaped to flat or diaphragm-like (Fig . 6) . In some cases the chordac tendineae and papillary muscles were normal, whereas in other instances they were shortened, thickened, fibrotic or fused, or even completely incorporated in the endocardial fibroelastotic process . In the classic funnelshaped valve, the chordae tendineae had often completely disappeared . COMMENTS

The present study includes a series of cases of congenital mitral stenosis in which the left ventricle was either larger than normal or only slightly reduced in size, thus excluding the "hypoplastic left heart syndrome ." The cases are classified into various anatomic complexes according to the associated cardiovascular lesions (Table i) . Pulmonary hypertension was



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present in the majority of the patients studied, with the pulmonary artery pressure approaching the systemic level in those with left atrial pressures of 20 mm . Hg or more. In all 3 pathologic groups the mortality rate was high in infancy, and only about a third of the children survived the second year of life . Group I: In isolated mitral stenosis the valvular obstruction varied from mild to severe, leading to varying ages of onset of the clinical symptoms and cardiac decompensation . The pulmonary artery pressures ranged from normal to systemic levels . More than a half of these children had an elevated pulmonary vascular resistance, the highest incidence in children above 3 years of age, suggesting a progressive increase of resistance with age . Group 1I: A second group of patients, in addition to mitral stenosis, had either other obstructive left-sided lesions or a patent ductus arteriosus, or both . The patent ductus arteriosus, when present, was usually large, and the obstruction occurred at the mitral valve, aortic valvular or subvalvular region and/or the aortic isthmus . Left ventricular endocardial fibroelastosis was probably part of the same pathologic process whichh affected the cardiac valves . While in some of these cases the mitral valve lesion was truly obstructive, in other autopsyproved cases the mitral valve was smaller than normal (its size usually correlated well with the size of the left ventricle), but its structural changes were mild ; in these cases, the elevated left atrial pressure was secondary to increased left ventricular diastolic pressure resulting from left ventricular obstruction and endocardial fibroelastosis . The pulmonary artery pressure in Group n varied from normal to systemic levels . Almost all cases with a patent ductus arteriosus had severe pulmonary hypertension, a small left to right shunt, and frequently a right to left shunt . More than half of the children in this group succumbed during the first three months of life, particularly those with aortic steriosis (83 %) : in contrast, the mortality rate in this age group was quite low in Groups r and n . Group III: Cases of congenital mitral stenosis with a ventricular septa] defect, but no other associated lesions, form another well defined pathologic complex with a better prognosis than that of the previous group. Although all patients in this group have severe pulmonary hypertension and an elevated pulmonary vascular resistance, the left to right shunt is usually still

moderately large (in some cases the shunt is bidirectional), and survival beyond 5 years of age is not rare . From the clinical standpoint, congenital mitral stenosis was usually manifested by cardiac decompensation and a rapidly deteriorating course in infancy (three-fourths of the cases) . Some of the characteristic auscultatory features of acquired mitral stcnosis, e .g ., the mitral opening snap and apical presystolic murmur, were infrequent in the congenital variety . However, a diastolic rumbling murmur at the apex was present in more than half of our cases. The electrocardiogram was consistent with right ventricular overload and combined atrial overload in almost all cases . Left ventricular overload occurred when an associated aortic stenosis or ventricular septal defect was present . The classic cardiac silhouette of acquired mitral stenosis and the radiologic findings of left atrial enlargement were often absent in young infacts, while pulmonary venous congestion was prominent . The surgical mortality for congenital mitral stenosis is still high ; but in isolated series, open mitral valvotomy has been reasonably successful . Very little information is available regarding postoperative hemodynamic evaluation of these patients . SUMMARY

This study consists of a detailed analysis of the clinical, hemodynamic, surgical and pathologic findings of 23 children with congenital mitral stenosis and 99 additional cases from the literature. These cases were grouped into three major pathologic complexes! (1) the isolated form ; (2) the form associated with other obstructive left-sided heart lesions (coarctation of the aorta, aortic stenosis) and a patent ductus arteriosus, or both ; and (3) the type associated with a ventricular septal defect . Clinical observations indicate a high mortality rate in infancy secondary to early and refractory cardiac decompensation . In the majority of instances there is severe pulmonary hypertension which approaches systemic levels when the mean left atrial pressure reaches 20 mm . Hg . The surgical mortality is still high, and an objective assessment of the operative results is not yet available . ACKNOWLEDGMENT We acknowledge Dr . Gertrude Novak's valuable assistance in reviewing the pathologic specimens (Cook County Children's hospital, Department of Pathology) . THE AMERICAN JOURNAL OF CARDIOLOGY

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