The Parachute Mitral Valve Complex: Angiographic Observations

The Parachute Mitral Valve Complex: Angiographic Observations* Joseph H. Yahinirf Abralwm Shern-Tov, M.D.;t

Victor Deutsch, M.D.;"" and Henry N, Neufeld,

M.D.,

F.C.C.P.f

Eight patients with parachute mitral valve complex were studied. Diagnostic angiocardiographic features stressed are: delay in the emptying of the left atrium; sickleshaped translucent-) at the mitral valve area; an eccentric filling defect in the left ventricle as a result of abnormally located, hypertrophied papillary muscle. Clinically, parachute mitral valve complex should be suspected in a patient with coarctation of the aorta and physical findings

of mitral valve disease, stenosis or insufficiency, particularly when subaortic stenosis and coarctation of the aorta are present. The correct diagnosis of parachute mitral valve deformity is of major importance when surgical correction is considered. Mitral valve replacement without correction of the subaortic stenosis, frequently associated, may not give the desired results.

T ^ h e p a r a c h u t e mitral valve c o m p l e x is a d e v e l o p -

retrograde aortography and left ventriculography, and in another (case 8) retrograde aortography alone were performed. The diagnosis of parachute mitral valve complex in five patients (cases 1 to 5 ) was based on the correlation between clinical, hemodynamic and angiocardiographic findings (Tables 1 and 2 ) . In three patients (cases 6 to 8 ) , the diagnosis was made at postmortem, on two of which (cases 6 and 8 ) no complete angiocardiographic studies were available.

-*- m e n t a l a n o m a l y c h a r a c t e r i z e d b y t h e c o e x i s t e n c e of t w o or m o r e o f f o u r obstructive, or potentially obstructive left-sided lesions. T h e s e a r e a supravalvular ring o f t h e left atrium, " p a r a c h u t e " d e f o r m i t y of t h e mitral valve, s u b a o r t i c stenosis a n d c o a r c t a tion o f t h e aorta. T h e a n o m a l y w a s first reported as a complex in an a n a t o m o p a t h o l o g i c report b y S h o n e and co-workers, w h o d e s c r i b e d eight patients, t h r e e 1

of t h e m with all f o u r a n d t h e r e m a i n d e r with only two o r three o b s t r u c t i v e lesions. Carey

and associates

2

d e s c r i b e d t h e radiologic

findings in four of t h e cases originally r e p o r t e d b y Shone a n d co-workers a n d c o n c l u d e d that a definitive diagnosis o f p a r a c h u t e mitral valve w a s n o t likely to b e m a d e on radiologic grounds alone. R e c e n t l y , however, P r a d o a n d c o l l e a g u e s , and c o - w o r k e r s claimed

that

4

Zamalloa

3

and Simon and associates

angiocardiography

may

5

have

contribute

greatly to t h e diagnosis of p a r a c h u t e d e f o r m i t y o f the mitral valve. We

report on o u r r a d i o l o g i c a n d angiocardio-

g r a p h i c e x p e r i e n c e with e i g h t c a s e s o f p a r a c h u t e mitral valve c o m p l e x , a n d discuss t h e v a l u e o f t h e s e p r o c e d u r e s in t h e diagnosis o f this a n o m a l y . MATERIAL AND METHOJK

Our patients underwent repeated clinical examinations, which included numerous 12-lead ECGs and chest radiograms during a follow-up period extending from one to eight years. All except one (case 8 ) underwent right heart catheterization. In six (cases 1 to 5 and 7 ) selective right angiocardiography, and in four (cases 3 to 5 and 7 ) selective 'From the Chaim Sheba Medical Center, Tel-Hashomer and Tel-Aviv University Medical School, Tel-Aviv, Israel. Department of Diagnostic Radiology and Heart Instituted Manuscript received July 19; accepted October 2. Reprint requests: Dr. Deutsch, Chaim Sheba Medical Center, Tel-Hashomer, Israel 00

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DEUTSCH ET AL

Clinical and Hemodynamic

Aspects

The patients were five girls and three boys ranging in age from 2 to 15 years (Table 1 ) . Five patients (cases 1, 2, 4, 5 and 8 ) gave a history of repeated upper respiratory infections; six patients (cases 1, 3-6 and 8) were in congestive heart failure when first examined; one (case 6 ) was treated for severe chronic anemia due to celiac disease. A great 3-4/6 apical pansystolic murmur was heard in four patients (cases 1, 2, 4 and 6 ) and an apical diastolic rambling murmur in six (cases 1-4, 6 and 7 ) . A parasternal systolic murmur was heard in five patients (cases 3-5, 7 and 8 ) and a parasternal diastolic murmur in two (cases 1 and 2 ) . The ECG displayed the presence of biventricular hypertrophy in five (cases 2-5 and 7 ) and of isolated left ventricular hypertrophy in three (cases 1, 6 and 8 ) . Four patients displayed a pattern of incomplete right bundle branch block (cases 1, 2, 3 and 5 ) . A mitral P wave was present in three patients (cases 4, 6 and 8 ) and P pulmonale in another one (case 2 ) . The results of the hemodynamic studies appear in Table 2. The right ventricular systolic pressure was mildly elevated in all patients except two (cases 3 and 7 ) , in whom it was markedly elevated. The pulmonary wedge pressure was elevated in five patients (cases 1, 2, 3, 6 and 7 ) ; it was not obtained in two (cases 5 and 8 ) . A left-to-right shunt at the ventricular level was documented in one patient (case 4 ) and at the pulmonary level in two (eases 3 and 7 ) . Radiologic

Findings

The plain chest roentgenograms showed some features common to all eight patients (Fig 3 ) . The heart was moderately to markedly enlarged. The left ventricle was markedly prominent and the left atrium moderately enlarged in all. Some degree of right ventricular enlargement was present in six patients (cases 2 - 7 ) . The aortic knob was normal in all. No CHEST, 65: 3, MARCH, 1974

Table 1—Clinical Case No.

Sex

1

Age

Symptoms

9

Repeated URI, congestive heart failure

Features Physical Findings

ECG

Loud first apical sound, loud pansystolic 4/6 apical murmur, split second sound. A increased. Slight parasternal early diastolic murmur, third heart sound and diastolic murmur at apex.

I R B B B , left ventricular hypertrophy.

2

15

Repeated URI, dyspnea, asymptomatic since age of 7 years.

Loud first apical sound. Pansystolic apical murmur with third sound and apical rumbling diastolic murmur. Second sound narrowly split. Blowing parasternal diastolic

P pulmonale, I R B B B , biventricular hypertrophy.

M

4

Congestive heart failure

Normal first apical sound. Apical diastolic murmur. Parasternal systolic thrill and murmur. Split second sound with increased pulmonic component.

I R B B B , biventricular hypertrophy with left predominance.

F

3

Congestive heart failure Repeated URI, asymptomatic since age of 4 years.

Parasternal systolic thrill and 4/6 parasternal pansystolic murmur. Apical pansystolic murmur radiating to left axilla with diastolic murmur.

P mitrale, biventricular hypertrophy.

M

3

Congestive heart failure, repeated URI

Stenotic; systolic murmur at left parasternal area.

I R B B B , biventricular hypertrophy.

F

10

Severe anemia due to celiac disease. Pulmonary edema.

Loud first apical sound with loud pansystolic and mild diastolic apical murmur. Split second sound with normal pulmonic component.

Mitral P wave, left ventricular hypertrophy.

F

8

Dyspnea

Parasternal systolic thrill and murmur. Apical diastolic murmur. Split second sound with accentuated pulmonic component.

Biventricular hypertrophy predominant left ventricular hypertrophy.

M

2

Repeated URI, congestive heart failure

Stenotic systolic murmur at left parasternal area.

Extreme left ventricular hypertrophy and mitral P wave.

URI = upper respiratory infection; I R B B B = incomplete right bundle branch block. rib notching or other x-ray signs of coarctation of the aorta were observed in any. The pulmonary vasculature was normal in one patient (case 1 ) . Signs of pulmonary venous hypertension were present in five (cases 2, 5, 6, 7 and 8 ) . In three others (cases 3, 4 and 7) there was evidence of pulmonary plethora which could readily be explained on the basis of an associated left-to-right shunt. In all six patients (cases 1-5 and 7) on whom selective right angiocardiography was performed, the levophase showed prolonged opacification of an enlarged left atrium (Fig 4 - 7 ) . In five out of six patients a thickened sickleshaped translucency was present at the mitral valve area both in systole and diastole and both in the frontal and lateral views (Fig 4 - 7 ) . Furthermore, in four patients (cases 1, 3 - 5 ) , a filling defect caused by a hypertrophied papillary muscle was visualized on the medial wall of the left ventricle below the mitral valve (Fig 4 and 7 ) and on the lateral wall of this ventricle (case 2 ) in one (Fig 5 ) . Subaortic stenosis of the discrete type (Fig 6) was demonstrated in three patients (cases 3, 4 and 7) and in two of them (cases 3 and 4) hypertrophic obstructive cardiomyopathy was also present. In one patient (case 5) only hypertrophic obstructive cardiomyopathy was demonstrated ( Fig 7 ) . The subaortic stenosis CHEST, 65: 3, MARCH, 1974

was also confirmed by pullback pressure recording across the left ventricular outflow tract in all the latter four patients. Coarctation of the aorta (Fig 4-6) was visualized in four patients (cases 1-3 and 8) and tubular hypoplasia of the third segment of the aortic arch (Fig 7) in two (cases 4 and 5 ) . In one patient (case 5) "cor triatriatum" was visualized (Fig7). Autopsy

Findings

Postmortem examination (Table 2 ) in three patients (cases 6-8) revealed parachute mitral valve, two of them (cases 6 and 7) with two papillary muscles but immediately adjacent to each other (Fig 2A) and the third (case 8) with a single papillary muscle (Fig 1 C ) . Supravalvular ring of the left atrium was also found in all three—in two of them (cases 6 and 7 ) a crescent-like webb (Fig 2 B ) , and in the third (case 8) and incomplete leaflet-like structure (Fig I B ) . In all three the supravalvular mitral ring was not significantly stenotic. Discrete subaortic stenosis (Fig 2A) was present in two patients (cases 6 and 7 ) and hypertrophic obstructive cardiomyopathy in all three (Fig 1A). Coarctation of the aorta (Fig 1A) was found in two patients (cases 6 and 8) and patent ductus arteriosus in one (case 7 ) .

PARACHUTE MITRAL VALVE COMPLEX

263

FIGURE 1 A - D (Case No. 7, parachute mitral valve, supravalvular ring of the left atrium, muscular hypertrophic subaortic stenosis and coarctation of the aorta). Necropsy specimen. A : General view of left ventricle and aorta showing extreme hypertrophy of the left ventricular wall. 2 : Subaortic stenosis and 3 , coarctation of the aorta. B: View of the mitral valve as seen from left atrium. A supravalvular membrane is marked by arrow. C and D: Left ventricular views. In C, a fused hypertrophied papillary muscle is seen (arrows). In D, thick, short and convergent chordae are marked by arrow. muscle, since t h e c h o r d a e converge to their papillary

DISCUSSION

T h e " p a r a c h u t e " d e f o r m i t y o f t h e mitral valve has b e e n defined b y S h o n e a n d c o - w o r k e r s

insertions.

as a r a r e

T h i s a n o m a l y was first reported b y S w a n and col-

form o f c o n g e n i t a l mitral stenosis p r o d u c e d b y a

l e a g u e s w h o d e s c r i b e d it as a "funnel"-shaped ste-

peculiar shortening o f t h e c h o r d a e t e n d i n e a e . T h e

nosis o f the mitral valve. T h e term " p a r a c h u t e " was

1

6

latter are inserted in a single large papillary m u s c l e

introduced b y S h i e b l e r and associates and adopted

and result in i m p e d i m e n t o f t h e normal excursion o f

b y S h o n e and co-workers.

7

1

T h e latter emphasized

the mitral leaflets. A c c o r d i n g to S h o n e a n d co-work-

t h e f r e q u e n t association of the malformation with

ers t w o papillary muscles a d j a c e n t to e a c h other m a y

coarctation of t h e aorta, subaortic stenosis of either

also result in t h e s a m e effect as a single papillary

the discrete type or t h e muscular hypertrophic or

FIGURE 2 A and B (Case No. 6, hypertrophic obstructive cardiomyopathy, parachute mitral valve, coarctation of the aorta, supravalvular ring of the left atrium.) Necropsy specimen. A : Left ventricular view showing the hypertrophy of the left ventricidar wall ( L V ) , the single hypertrophied papillary muscle of the mitral valve (PM) and the subaortic stenosis (arrow). B: Left atrial view seen from above showing the mitral valve; the arrows point to the supravalvular ring which in this case was probably not significant hemodynamically.

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CHEST, 65: 3, MARCH, 1974

Table 2—Hemodynamic Data, Cardioangiographic Oxygen Saturation

and Autopsy

Findings

Pressures mm Hg

No.

vcs

VCI

RA

RV

PA

Aorta

MRA

RV

1

71

70

69

68

67

95

3

38/o

PA 6

M Wedge Aorta

30/13

12

—

LV

Cardioangiographic diagnosis Coarctation of aorta, parachute

—

mitral valve 2

67

76

66

67

68

5

43/o

5

43/21

20

—

Coarctation of aorta, parachute mitral valve

3

60

75

60

68

70

98

3

75/a

5

75/35

26

80/62*

140/

0

1 0

Coarctation of aorta, discrete subaortic stenosis, HOC, PDA

4

71

68

63

80

79

90

2

35/o

5

35/6

7

75/60

125/7

Coarctation of aorta, discrete subaortic stenosis, HOC, VSD

5

59

—

56

57

—

—

3

40/o

5

—

—

100/50

150/o

10

Cor triatriatum, coarctation of aorta, HOC

6

73

66

66

66

66

3

38/o

3

36/5

20

Parachute mitral valve, coarctation of aorta, discrete subaortic stenosis, HOC, supravalvular ring of left atrium**

7

60

65

66

66

76

94

4

88/c

7

75/45

22

90/40

150/o

14

Parachute mitral valve, supravalvular ring of left atrium, discrete subaortic stenosis, HOC, P D A * *

8

—

—

—

93

150/75

Coarctation of aorta, parachute mitral valve, supravalvular ring of left atrium, H O C * *

VCS=vena cava superior; V C I = v e n a cava inferior; R A = right atrium; R V = right ventricle; P A = pulmonary artery; M R A = m e a n right atrial pressure; MWedge=mean wedge pressure; L V = l e f t ventricle; H O C = hypertrophic obstructive cardiomyopathy; P D A = p a t e n t ductus arteriosus; V S D = ventricular septal defect.

*Descending aorta. The pressure in the ascending aorta was 125/60.

both, and a supravalvular ring of the left atrium. If all four obstructive lesions w e r e present they considered it a c o m p l e t e form of the complex, w h i l e those with two or three lesions only were r e g a r d e d as forme fruste. According to S h o n e and c o - w o r k e r s 1

**Autopsy findings.

a n d a s u b s e q u e n t report b y G l a n c y and c o l l e a g u e s not all the a n a t o m i c obstructive lesions are h e m o d y n a m i c a l l y significant. F u r t h e r m o r e , the "parac h u t e mitral v a l v e " deformity is not an obligatory finding of the complex, a n d w h e n present does not

8

FIGURE 3 A - F (Cases 1-6). Plain chest roentgenograms of six different patients with parachute mitral valve complex. (The sequence of the films corresponds to those in Tables 1 and 2): Moderate to marked cardiomegaly and left ventricular enlargement is seen in all. Pulmonary venous hypertension is visible in cases 2, 5 and 6, pulmonary plethora in cases 3 and 4 and usual pulmonary vasculature in case 1. CHEST, 65: 3, MARCH, 1974

PARACHUTE MITRAL VALVE COMPLEX

265

coarctation of the aorta in the presence of clinical signs suggesting mitral valve obstruction or insufficiency. In fact, apical diastolic rumble was found in six out of eight patients ( c a s e s 1-4, 6 and 7 ) , and pansystolic apical m u r m u r suggesting mitral insufficiency in five ( c a s e s 1, 2, 4, 6 and 7 ) . T h e s e findings in the a b s e n c e of opening snaps, raise the possibility of the presence of parachute mitral valve complex. 4

T h e plain chest roentgenograms of our patients revealed moderate-to-marked left ventricular and mildto-moderate left atrial enlargement in all ( F i g 3 ) . It seems to us that these findings are not contributory for the diagnosis of parachute mitral valve complex.

FIGURE 4 (Case No. 4, parachute mitral valve and coarctation of aorta): Levophase of selective right angiocardiogram. The left atrium is enlarged. The mitral valve appears as a thickened sickle shaped translncency (horizontal arrows). A hypertrophied papillary muscle causes a filling defect on the medial wall of the left ventricle (vertical arrow). Coarctation of the aorta is marked by the upper arrow. always interfere with mitral valve functions; it may, in some cases, result in mitral regurgitation rather than stenosis. T h u s , a real p a r a c h u t e deformity of the mitral valve with a single papillary muscle was present in only three of the original eight cases reported b y S h o n e and co-workers,' while a m o n g the three cases reported b y G l a n c y and c o l l e a g u e s one had mitral obstruction, one had normal valve function and a n o t h e r mitral regurgitation. 8

8

In our material the diagnosis of p a r a c h u t e mitral valve complex was entertained in patients with

T h e most useful confirmation in our case c a m e from the angiocardiogram which showed some of t h e characteristic anatomic features of the complex, thus suggesting the presence of its associated anomalies. In five out of six patients ( c a s e s 1-5) selective right ventriculography demonstrated a delay in the emptying of the left atrium and a sickle-shaped translucency in the mitral valve area ( F i g . 4 - 7 ) . In this respect it should be stated that Mehrizi and cow o r k e r s described such a translucency in their cases of p a r a c h u t e mitral valve with supravalvular mitral rings and considered it as characteristic for a supravalvular mitral ring. 9

I t seems to us, however, that the absence of this a n g i o c a r d i o g r a p h i c sign does not rule out the prese n c e of such a ring, as it occurred in one of our patients ( c a s e 7 ) . Theoretically, a pressure gradient across the supravalvular ring of the left atrium may b e recorded in such cases as was documented by

FIGURE 5 (Case No. 2, parachute mitral valve and coarctation of aorta): Levophase of selective right angiocardiogram. A and B frontal and lateral views, respectively. In both views the thickened mitral valve is marked by oblique arrows. A hypertrophied papillary muscle causes a filling defect on the anterolateral wall of the left ventricle (lower horizontal arrows). Coarctation of the aorta is marked by the upper arrows.

FIGURE 6A and B (Case No. 3, discrete subaortic stenosis, coarctation of aorta and patent ductus arteriosus): Selective left ventriculography frontal and lateral views, respectively. In A a subaortic chamber and subaortic membrane are visualized (lower arrows). The upper arrow points to the coarcted segment of the aortic arch and the patent ductus arteriosus. B is the late phase of left ventriculography, lateral view. The left atrium and left ventricle are visualized by the contrast material shunted through the patent ductus arteriosus into the pulmonary circulation. The arrows point to a thickened mitral valve.

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CHEST, 65: 3, MARCH, 1974

FIGURE 7 A-C (Case No. 5 , parachute mitral valve, cor triatriatum, subaortic stenosis, tubular hypoplasia of third segment of aortic arch): Levophase of selective right angiocardiogram. A and B are frontal views in systole and diastole respectively and C lateral view in systole. In A and B (arrow no. 3 ) oblique arrow points to a membrane dividing the left atrium. The mitral valve is sickle shaped (arrow no. 1) and the posterior papillary muscle is hypertrophied (arrow no. 2 ) . Mild tubular stenosis of the third part of the aortic arch is also seen. Marked hypertrophy of the left ventricular is apparent (dotted lines). In C subaortic stenosis (arrow no. 4 ) , sickle shaped mitral valve (arrow no. 1) and the hypertrophied posterior papillary muscle (arrow no. 2 ) are visualized. L y n c h and c o - w o r k e r s . H o w e v e r , in our view the close proximity of the supravalvular mitral ring to the mitral valve as reported originally b y S h o n e and c o - w o r k e r s and confirmed in our p a t h o l o g i c specimens renders such m e a s u r e m e n t extremely difficult. I f such a recording is not available, the a b o v e m e n tioned sickle-shaped translucency should b e considered an indicator of mitral obstruction whose n a t u r e remains uncertain. 10

1

It is interesting that in o n e of our patients ( c a s e 5 ) , a diaphragm with a b r o a d b a s e dividing the left atrium into a larger u p p e r and smaller distal part was recognized in the levophase of selective right angiocardiography ( F i g 7 ) . T h e relative proximal location of the m e m b r a n e c o n f o r m e d more with the diagnosis of cor triatriatum than with a supravalvular mitral ring, a d e f e c t w h i c h has not b e e n hitherto described a m o n g those associated with parachute mitral valve c o m p l e x . 8

T h e most characteristic a n g i o c a r d i o g r a p h i c f e a tures, b o t h in the literature and in our cases, was t h e filling d e f e c t caused b y a h y p e r t r o p h i e d a n d a b normally located papillary muscle w h i c h was d e m onstrated b y selective right or left angiocardiography or by both. I n four of our five cases, this filling defect was located at the m e d i a l wall of the left ventricle ( F i g s 4 and 7 ) , as it was in the cases reported b y Prado and a s s o c i a t e s and Z a m a l l o a and colleagues. Only in o n e of our patients ( c a s e 2 ) was the filling d e f e c t observed on the lateral w a l l of the left ventricle ( F i g 5 ) . Zamalloa and c o - w o r k e r s stated that a n o r m a l papillary muscle c a n not b e recognized on the left ventricular angiocardiogram. In our experience, however, a n d in t h e e x p e r i e n c e of o t h e r s , the normal papillary muscle c a n occasionally b e visualized b y selective left ventriculography. T h e anterior papillary muscle is seen along the anterosuperior surface and the posterior papillary m u s cle along the posteroinferior surface of the left ventricle. F u r t h e r m o r e , if left ventricular outflow 8

4

4

5

CHEST, 65: 3, MARCH, 1974

obstruction is present, the symmetrically hypertrophied papillary muscles b e c o m e m o r e prominent on the left ventricular a n g i o g r a m . C o a r c t a t i o n of t h e aorta at t h e typical location was d e m o n s t r a t e d b y a n g i o c a r d i o g r a p h y in four patients ( c a s e s 1-3, a n d 8 ) , and t u b u l a r hypoplasia of the third segment of the aortic arch in the other two ( c a s e s 4 and 5 ) . W e b e l i e v e that t h e latter, t h e t u b u l a r hypoplasia, m a y b e considered an equivalent of coarctation. D i s c r e t e subaortic stenosis or h y p e r t r o p h i c o b structive c a r d i o m y o p a t h y or b o t h h a v e b e e n reported in the p a r a c h u t e mitral valve c o m p l e x . 1

4

It is to b e stressed that in our m a t e r i a l all four patients w h o h a d discrete s u b a o r t i c stenosis ( c a s e s 3, 4, 6 and 7 ) h a d in addition h y p e r t r o p h i c obstructive c a r d i o m y o p a t h y . In a n o t h e r t w o ( c a s e s 5 and 8 ) h y p e r t r o p h i c obstructive c a r d i o m y o p a t h y only was present. T h e a n g i o c a r d i o g r a p h i c differentiation b e tween the two types of s u b a o r t i c obstruction was d e s c r i b e d b y us r e c e n t l y . In this respect it should b e recalled that t h o r a c i c a o r t o g r a p h y is extremely helpful in delineating the discrete s u b a o r t i c stenosis. 12

I t follows from the a b o v e that t h e diagnosis of p a r a c h u t e mitral valve c o m p l e x should not b e very difficult. In a p a t i e n t with coarctation of the aorta showing a delay in the e m p t y i n g of the left atrium, a sickle-shaped t r a n s l u c e n c y in t h e mitral valve area, a b n o r m a l l y located, a filling d e f e c t in the left ventric l e suggesting a h y p e r t r o p h i e d papillary muscle particularly in association with s u b a o r t i c stenosis, disc r e t e or h y p e r t r o p h i c or b o t h , the diagnosis of parac h u t e mitral v a l v e c o m p l e x should b e heavily suspected. T h e existence of a p a r a c h u t e mitral valve m a y have p r a c t i c a l i m p o r t a n c e if surgical correction is considered. I t should alert the surgeon for eventual mitral valve r e p l a c e m e n t . I f mitral valve replacem e n t is considered, the f r e q u e n t association of disc r e t e s u b a o r t i c stenosis or h y p e r t r o p h i c obstructive

PARACHUTE MITRAL VALVE COMPLEX

267

c a r d i o m y o p a t h y or b o t h should b e carefully evalua t e d a n d c o r r e c t e d b e f o r e mitral valve r e p l a c e m e n t is d o n e . REFERENCES

1 Shone JD, Sellers RD, Anderson RC, et al: The developmental complex of "parachute mitral valve," supravalvular ring of left atrium, subaortic stenosis and coarctation of aorta. Am J Cardiol 11:714-725, 1963 2 Carey LS, Sellers RD, Shone J D : Radiological findings in the developmental complex of parachute mitral valve, supravalvular ring of left atrium, subaortic stenosis and coarctation of aorta. Radiol 82:1-10, 1964 3 Prado S, Levy M, Varco R: Successful replacement of "parachute" mitral valve in child. Circulation 32:130-133, 1965 4 Zamalloa O, De Franceschi A, Leachman RD: Clinical and angiographic diagnosis of the "parachute mitral valve." Acta Cardiol 24:101-111, 1969 5 Simon AL, Friedman WF, Roberts WC: The angiographic features of a case of parachute mitral valve. Am Heart J 77:809-813, 1969

6 Swan H, Trapnell JM, Denst J : Congenital mitral stenosis and systemic right ventricle with associated pulmonary vascular changes frustrating surgical repair of patent ductus arteriosus and coarctation of the aorta. Am Heart J 38:914-923, 1949 7 Schiebler GL, Edwards JE, Burchell HB, et al: Congenital corrected transposition of the great vessels: A study of .33 cases. Pediat ( Suppl) 27:851, 1961 8 Glancy DL, Chang MY, Dorney ER, et al: Parachute mitral valve. Further observations and associated lesions. Am J Cardiol 27:309-313, 1971 9 Mehrizi A, Hutchins GM, Wilson EF, et al: Supravalvular mitral stenosis. J Pediat 67:1141-1149, 1961 10 Lynch MF, Ryan NJ, Williams GR, et al: Preoperative diagnosis and surgical correction of supravalvular mitral stenosis and ventricular septal defect. Circulation 25:854861, 1962 11 Shem-Tov A, Deutsch V, Yahini JH, et al: Cardiomyopathy associated with congenital heart disease. Br Heart J 33:782-793, 1971 12 Deutsch V, Shem-Tov A, Yahini JH, et al: Subaortic stenosis (discrete form). Classification and angiocardiographic features. Radiol 101:275-286, 1971

Health Problems Due To Increased Use of Coal The pressing inadequate supply of fuel oil as energy source has brought about an inevitable recourse to increased use of coal by all concerned. Coal reserves of the world amount to about five trillion tons, of which 9 7 percent is in the northern hemisphere and about 4 0 percent in North America. West Virginia is the leading coal mining state in this country. Authoritative information is available on air pollution resulting from impurities of coal, particularly sulfur dioxide and also on silicosis as a potential hazard of coal mining. Data relative to coal workers' pneumoconiosis are numerous but somewhat obscured by divergent observations, interpretations and conclusions. A brief review of the basic features of this condition may aid in its clearer understanding and appraisal. Pertinent pulmonary pathologic changes were accurately portrayed bv Cough, J ( J Path and Bact 5 1 : 2 7 7 , 1940; Occup Med 4 : 8 6 , 1 9 4 7 ) , Fletcher, C M (Brit M J 1 : 1 0 1 5 , 1 9 4 8 ) and Heppleston, A G (J Path and Bact 6 6 : 2 3 5 , 1 9 5 3 ) . Salient characteristics are: deposition of macrophages laden with coal particles of 0.5 to 5 microns in size around the respiratory bronchioles causing obliteration of some of the adjacent vesicular structures, alveolar ducts and alveoli throughout the lung but more so in the lower lobes; small amount of fibrosis at the same site; concomitant atrophy of the respective bronchiolar muscles; dilatation of implicated respiratory bronchioles resulting in compression of alveolar ducts and sacs and in focal emphysema. T h e latter is not visualized in x-rays and is entirely different from emphysema in patients with silicosis; deposition of coal particles in the adventitia of small pulmonary arteries. Rasmussen et al (Am Rev Resp Dis 9 8 : 6 5 8 , 1 9 6 8 ) described some of the coal nodules as consisting of aggregation of dust macrophages with small amount of reticulin and also as coal maculae with collagen fibers in a haphazard arrangement, often stellate in appearance. They observed in about 1,000 autopsies that 15

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percent showed predominantly perivascular and diffuse dust retention. In the most marked instances of perivascular involvement the lungs had very high dust content with a striking lack of nodule formation. Naeye, R L et al (Annual Meet Am Assoc Path and Bact, 1970) observed in autopsy studies that as the result of occupational exposure, cor pulmonale was very common in Appalachian soft coal miners over the age of 5 0 years. Exposure to coal dust varied from less than 2 0 years to 3 0 years or more. Clinical studies led to the assertion that in coal workers' pneumoconiosis, pulmonary x-raychanges do not necessarily correspond to the disability of the individual. Such x-ray changes vary from delicate reticulation to microgranular and coalescent irregular alterations of 1 cm or larger. Significant respiratory impairment may be recorded in coal workers with minimal radiologic evidence of pneumoconiosis and without overt chronic obstructive airway disease. Some clinicians attributed pulmonary functional impairment to decreased diffusion capacity. Others considered impaired pulmonary ventilation as the immediate cause. Also, coexistent emphysema has been considered as a causal factor. Possible contributory role has been attributed to minute quantities of silica inhaled with coal dust, and to superimposed infection. Schepers, G W H (in Harris, M C and Shure, N: Sensitivity Chest Diseases, Philadelphia, Davis, 1 9 6 4 ) comments on the possible allergenicity of coal. The latter is derived through diagenesis from huge trees and other plants sunk into swamps, covered with rocks and sediment, subjected to extremely high pressure and temperature in the absence of air, some 4 5 0 million years ago. Thus, in its origin, coal represents vegetable matter. It may contribute to allergic bronchospasm and dyspnea in patients with coal workers' pneumoconiosis. Andrew L. Banyai, M.D.

CHEST, 65: 3, MARCH, 1974