Scand J Thor Cardiovasc Surg 13: 1-7, 1979
SURGICAL TREATMENT OF EBSTEIN'S ANOMALY Etirly cind La!i>Results in S ~ ~ ~Cotisrcirtivc e t i Ccises
Arplid Peterffy and Viking Olov Bjork Frori7 the Thorcicic Si4rgic~ilClitiic. KrirolitisAri SjrrXhir.srt. SrocXholni, Swedeti
(Submitted for publication August 14, 1978)
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AhrrLict. The surgical treatment of Ebstein's anomaly is
discussed on the basis of our experience with 7 patients who underwent operation at this clinic during the last ten years. The age of the patients (2 males, 5 females) ranged from 17 to 47 years (mean 27 years) at the time of operation. Two patients were in functional class 11 and five in classes 111 or IV (N.Y.H.A.). The Wolff-Parkinson-White syndrome was Concomitant in 2/7 cases and patent foramen ovale or atrial septal defect (ASD) with right-to-left shunt was present in 6/7 cases. The valvular anomaly was typical in 5 patients and stenosis of displaced tricuspid leaflets into right ventricular outflow region was detected in two patients. Tricuspid valve replacement (TVR) with disc valve prosthesis was performed in 5 patients (BjorkShiley model in 4 cases, Kay-Shiley model in one) and tricuspid valve commissurotomy in two patients. All six patients with interatrial communication underwent closure of this communication simultaneously. One patient had concomitant epicardial mapping and attempted division of the anomalous conduction pathways was unsuccessful. This patient died on the 14th postoperative day from ventricular fibrillation. No other early or late mortality was recorded. Life-long anticoagulation therapy was introduced in all 5 patients with TVR. Thrombotic malfunction of the prosthetic valves necessitated re-operation and new prosthetic valve replacement in two patients 15 and 16 months after the first TVR. One of these patients had recurrent prosthetic thrombosis twice which was successfully treated with streptokinase. The other patient's prosthesis is functioning well 18 months after re-operation. All 6 long-term survivors were impjoved and remained in good condition, in functional class I , I. 3, 3 , 8 , 9. and 10 years, respectively, after operation.
The anatomical characteristic of Ebstein's anomaly is the varying degree of downward displacement of the septal and posterior leaflets of the tricuspid valve with their chordae tendinae and their papillary muscles. The anterior leaflet is usually large and has a normal position. An atrialized right ventricular chamber is interposed between a large right atrium and a small functional ventricular chamber composed of the apical and infundibular parts of the right ventricle. An interatrial communication, either I - 792913
patent foramen ovale o r secundum type defect. is usually present. The functional abnormalities are most often tricuspid incompetence o r more seldom stenosis, low cardiac output due to small ventricular volume and/or interatrial right-to-left shunt. Rhythm disturbances, such as conduction defects (right bundle branch block, pre-excitation), paroxysmal tachycardia and arrhythmia are often concomitant. The atrium and the atrialized part of the right ventricle reveal identical pressures, but their electrical activities and contractions are not synchronized as the atrialized part of the ventricle behaves in this respect as the functional part of the right ventricle. The atrialized part of the right ventricle distends during atrial systole and any contraction of this chamber during atrial diastole only forces the blood back into the atrium (Hardy & Roe, 1969). Ebstein's anomaly has been submitted to reconstructive surgery for the last 15-20 years. The reconstructive procedures are tricuspid valve repair by annuloplasty o r valvular transposition, tricuspid valve replacement (TVR) with o r without exclusion of the atrialized part of the right ventricle and simultaneous closure o r non-closure of the interatrial communication. These methods seem to be much more effective than the palliative shunt operations (Watson, 1974). The indications for surgical treatment and the optimal operative method are still controversial.
CLINICAL MATERIAL This report reviews our experience of corrective surgery for Ebstein's anomaly on the basis of 7 consecutive patients operated on at this clinic during the last 10 years (May 1968 to October 1977). The pre-operative clinical status of our patients is summarized in Table I . There were 2 males and 5 females with a mean age of 27 years
Table I . Prr-opmitivi. c~liriic,rrl.ct(rtrr,s
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RAH = right atrial hypertrophy, RBBB = right bundle branch block. W-P-W atrioventricular block grade I Pat. No.
Functional cia\\
= Wolff-Parkinson-White
Working capacity (W)
Sex
Age (y.)
Clinical signs
1
M
24
Cyanosis, clubbing, cerebral emboli, tachycardiac attacks, systolic murmur
Ill
'5
2
F
27
Cyanosis, clubbing, arterial thrombosis, no heart murmur
Ill
75
3
F
23
Cyanosis, clubbing, arterial thrombosis, syncope, tachycardiac attacks. systolic murmur
IV
32
4
F
17
Cyanosis. clubbing, tachycardiac attacks. systolic and diastolic murmurs
Ill
-
5
M
24
I11
60
6
F
31
Cyanosis, tachycardiac attacks, systolic murmur Atrial fibrillation attacks, systolic and diastolic murmurs
II
I20
7
F
47
II
110
Cyanosis. tachycardiac attacks. systolic murmur
(range 17-47 years) at the time of operation. The mean duration of pre-operative cardiological observation was 20 years. Two patients were in functional class 11, 4 in class I l l and one in class IV ( N . Y . H . A . classification). The heart volume was enlarged in average 761 t 2 6 0 ml/mYBSA and the physical working capacity was decreased in average 70.3k39.2 W. The 6 patients. who had interatrial communication. displayed increased haemoglobin (180.6k32.5 g/l) and haematocrit (55.3+ 11.8%) levels and decreased arterial oxygen saturation (89.l+S.7%) a s the result of the right-to-left shunt. The Wolff-ParkinsonWhite (W-P-W) syndrome was concomitant in 2 cases. he-operative catheterization was performed in 5 patients and cardio-angiography in 6 patients. Results of these investigations are summarized in Table 11.
OPERATIVE FINDINGS AND PROCEDURES Median sternotomy and cardiopulmonary bypass with beating heart were used in all patients and moderate hypothermia (32°C) was added in 3 cases. The malformation was corrected through a right atriotomy. The ascending aorta was cross-clamped during the time of closure of the interatrial communication. The operative findings and procedures are summarized in Table 111. Pronounced valvular incompetence was found in 5 patients and the displaced tricuspid leaflets were stenosed into the right ventricular outflow tract in the remaining two patients. lnteratrial communication was present in 6 cases. Aneurysmal dilatation and paradoxical distension of the atrialized part of the right ventricle were observed in 4 patients.
ECG alteration
\yndrome. AV BI I Heart volume (ml/mLBSA)
RA H RBBB w-P-w RBBB
730
RAH RBBB
700
370
RA H RBBB w-P-w
I 020
RAH RBBB
1 050
RAH RBBB AVBI I RBBB
950
510
Tricuspid valve replacement with low-profile disc valve prostheses was performed in all 5 patients with valvular incompetence. The Bjork-Shiley prosthesis was used in 4 cases and the Kay-Shiley model in one. The tricuspid valve was excised and the prosthesis inserted with mattress sutures. The prosthesis was placed above the coronary sinus on the atrial septum in 3 cases and on the ventricular septum far below the coronary sinus to avoid injury of the bundle of His in 2 cases. No A-V block was recorded postoperatively. On the anterior wall. the prosthesis was fixed to the insertion of the excised anterior leaflet. In patient '6, we attempted to repair the valvular incompetence by performing a d e Vega annuloplasty, but without success. The intra-operative pressure recording revealed that the incompetence had not resolved and tricuspid valve replacement was necessary (Fig. I ) . Tricuspid commissurotomy was performed on the stenosed displaced leaflets into the right ventricular outflow region in 2 patients. The interatrial communication was closed simultaneously in order to prevent paradoxical emboli and t o discontinue the right-to-left shunt in all six patiwts. In patient No. 4, attempted division of the anomalous conduction pathways after epicardial mapping failed as the pre-excitation remained unchanged after operation. No attempts were made to exclude the atrialized right ventricle chamber.
RESULTS Mortcrlily. The o p e r a t i v e m o r t a l i t y wa\ o n e p a t i e n t , No. 4, with c o n c o m i t a n t W-P-W s y n d r o m e a n d in
=
Haemoglobin, g/I Haematocrite. 72
prosthesis was replaced with the new Bjork-Shiley convexo-concave prosthesis (Bjark, 1978). Both patients survived re-operation without complications. The new prosthesis in patient No. 5 thrombosed 12 months after re-operation. On that occasion, the malfunction of the prosthetic valve was successfully treated with streptokinase (Kabikinas:'$). Four months later the anticoagulation ti-eatment was temporarily interrupted in consequence of a traffic accident and the prosthetic malfunction recurred again. The new thrombolytic therapy with streptokinase was successful and the prosthetic valve is now functioning well. F o l l o ~ w p .Follow-up data are avaible on all 6 long-term survivors, 12-125 months (mean 69 months) after surgical correction. The patients were re-examined at this clinic. All 6 were improved, belonged to functional class I without cardiac complaints and are now working. The physical working capacity at the bicycle ergometei- test had increased in average from 70.3k39.2 W to 95.8k28.4 W . This change was not significant. The heart volume in upright position had decreased significantly. Haemoglobin, haematocrit and arterial oxygen saturation had returned to normal levels (Table IV).
Arterial O2 saturation
(76)
''8 72
91
I60 48
91
I90
85
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57 83
I80
60
214 66
85
I38 40
100
156
89
44
whom the intra-operative division of the anom'd I OLlS conduction pathways was unsuccessful. She died on the 14th postoperative day of ventricular fibrillation. No other early or late mortality was recorded. Complicutioris. The major complication was thrombotic malfunction of the prosthetic valves. Thrombotic fixation of the tilting disc in a semiopen position was observed four times in two patients, despite adequate anticoagulation three times, an incidence of 15.2 per 100 patient years. Patients Nos. 4 and 6 were re-operated on 15 and 16 months after the first TVR and the thrombosed
Table 11. Prr-opmiriipe
DISCUSSION The severity of Ebstein's anomaly varies considerably. There are reports of patients who survived over 70 years (Adams & Hudson, 1956; Makous & Van der Veer, 1966). The more serious forms shorten life expectancy considerably (Bialostozky, Horowitz & Espino-Vela, 1972). The prognosis is not so favourable with associated cardiac lesions, more marked cyanosis. extreme cardiomegaly and
c.titlirtrri,7Lition dtitti (rnrnHg) titid
r~.sirltsc!f'ritigioc.Lirdiogrtii~li?'
M=mean pressure, S=systolic pressure, D=diastolic pressure, eD=end-diastolic pressure, R=right, L=left. TI= tricuspid insufficency, Typical=typical Ebstein's malformation. PCV =pulmonary capillary venous pressure Right ventricle
Right atrium Pat. No.
PCV
I 2 3 4 5 6 7
Pulmonary artery
f
Sex M
a-
v-wave
M F F F M F
10
13
7
4 6 4 13 15 N o catheterization N o catheterization 12 14 16 7 1 3 4
S
eD
19
8 8
21 30 22 27
S
D
M
M
19
9
15
-
3
-
-
-
21 20
10
-
11 12
22 22
10
15
13
9
12
9
Direction of shunt
Result of angiocardiography
R-, L Typical, TI R-, L TI k R-, L Typical, TI R-, L Typical, TI N o angiocardiography N o shunt Typical, TI RZL TI Q
+++ ++
+++
+++
4
A . PPtei:ff:v t i t i r l V . 0 . BjjiirX
Table I1 I . Operriti\ie findings, type o f o p i w t i o n
titid
po.stopi'rtitii'i, condition
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K-S = Kay-Shiley prosthetic valve, B-S = Bjork-Shiley prosthetic valve, B-Scc prosthetic valve, F c.=functional class (N.Y.H.A.)
=
Bjork-Shiley
convexcxoncave
Pat. No.
Sex
Age (y.)
Description of valvular lesion
Description of atrialized ventricle
Septa1 defect
Surgical procedure
Fixation of prosthesis
1
M
24
Typical Ebstein, tricuspid insufficency
Aneurysmal dilatation, paradoxical distension
F
27
Slight dilatation, no paradoxical distension
3
F
23
Tricuspid stenosis in right ventricle outflow tract Typical Ebstein, tricuspid insuftiency
Aneurysmal dilatation, paradoxical distension
ASD sec. type
1968.05.02 TVR K-S 8, closure ASD 1969.06.22 open commissurotomy, closure ASD 1970.05.25 TVR B-S 27, closure ASD
Above coronary sinus
2
ASD sec. tY Pe ASD sec. tY Pe
4
F
17
Typical Ebstein, tricuspid insufficency
Aneurysmal dilatation, slight paradoxical distension
ASD sec . type
1970.12.01 TVR B-S 3 I closure ASD
Above coronary sinus
5
M
24
Typical Ebstein, tricuspid insufficency
Aneurysmal dilatation, paradoxical distension
Patent foramen ovale
Below coronary sinus
6
F
31
Typical Ebstein, tricuspid insufficency
Slight dilatation, no paradoxical distension
No
197S.10.21 TVR B-S 3 1 closure foramen ovale 1975.11.05 TVR B-S 31
7
F
47
Tricuspid stenosis in right ventricle outflow tract
Slight dilatation, no paradoxical distension
ASD sec. tY Pe
1977.10.28 open commissurotomy, closure ASD
-
is bad with the appearance of congestive heart failtire (Kumar, Fyler, Miettinen & Nadas, 1971). Our experience and that of others proves that the most favourable timing of the corrective operation is between 15 to 40 years (Cams, Meisner, Paek & Sebening, 1977). Palliative procedures, such as Glenn's anastomosis, can be recommended for in-
-
Above coronary sinus
Below coronary sinus -
fants and very young children who need surgery (Najafi, Hunter, Dye, Javid & Julian, 1967; Mannix & Bert-oya. 1971). Surgical correction seems to be recommendable for patients in funtional classes 111 and IV, patients with sinking cardiac status, moderate to severe cyanosis, paradoxical emboli or arterial thrombosis
Table IV. Pre- rind postoprrcrtii~rc h n g r . s o f 5 diffhnt p(rrrimt~tt~r.s W,,,=maximum working capacity on bicycle ergometer tolerance test, Pre-op. .i=mean value of variable pre-operative, Postop. i = m ean value of variable postoperative, S.D.=standard deviation, d=mean difference, n=number of observations. p=probability level, Sign. =significance Wmtu
Heart volume
(W)
(ml/m' BSA)
Pre-op. .i. S.D.
70.3 k39.2
718
181.0
k 256
k35.4
PostOD.
95.8 k28.4 25.5 6
533 ? I40 - 185 6 0.5
*
Haemoglobin g/l)
**
Haematocri t (%)
Arterial 0, saturation %
54.5 ? 12.7
k5.5
40.5
k9.7 - 14.0 6
10.02
*
90.1 98.8 k0.9 8.7 6 10.01
**
Sirrgicril trrritmrnt of Ehstrin's tinomriiy
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4oommlbp
Postoperative complications
Management of complications
Results Follow-up
No
No
No
No
Good 1Fc. 125 months Good 1Fc. 110 months
No
No
Ventricular fibrillation
Defibrilation
Prosthetic thrombosis, thrombosis x 2. new prosthesis Prosthetic thrombosis
1977.02.I I new TVR B-Scc. thrombolytic treatment x 2 1977.02.17 new TVR B-Scc
Tach ycardiac attacks
Beta blocking agent
5
-
Good I Fc. 99 months Death 14th postop. day Good I Fc. 36 months Good I Fc. 36 months Good I Fc. 12 months
and right ventricular outflow obstruction (McFaul, Davis, Giuliani, Ritter & Danielson, 1976). These criteria were present in our cases. The rhythm disturbances alone do not constitute an operative indication, since they can remain unchangzd after operation, as in one of our patients who also required beta blocking treatment postoperatively. The WP-W syndrome is an exception, in that the cutting through of anomalous conduction pathways could stop the rhythm disturbance (Sealy , Gallagher, Pritohett &Wallace, 1978). In one of our two cases, the pre-excitation disappeared after the operation as a result of the division of these pathways, as in the case reported by Cartwright et al. (1964). In the other case, the epicardial mapping and attempted division were unsuccessful, which could be ascribed to the difficulty of the method and our lack of experience in this field. The optimal surgical correction is not yet defined. This is because personal experience includes less than 10 cases in the majority of reports (Carpentier, Deloche, Relland, Fabiani, Forman, Camillen, Soyer & Dubost, 1974; Wada, Komatsu
0)
Fix. 1 . Intra-operative registration of right atrial ( PR A , mmHg) and right ventricular ( P,(, , mmHg) pressures. The upper part registered after de Vega annuloplasty and the lower part after TVR.
& Tanaka, 1977). On the other hand, the variations of pathology and anatomy make this problem more difficult and nearly every case requires a highly individualized surgical solution (Mannix & Berroya, 1971). Our observations suggest that there are two clearly distinguished clinical and pathological forms of Ebstein's anomaly. One form is the typical displacement of the valvular apparatus with different degrees of tricuspid insufficiency. The aneurysmal dilatation of the atrialized ventricular chamber is secondary to the regurgitation. The paradoxical movement of this chamber is a passive distension of the thin wall during the ventricular systole when blood flows back through the incompetent tricuspid valve. It is not a true paradoxical contraction as McFaul et al. (1976) believed. This assertion is supported by the report by Senno, Ohishi, Nawa, Teramot & Sunada (1976), who observed disappearance of the paradoxical movement after TVR in atrioventricular position. The other form is the obstructive type. In these cases the displaced valvular apparatus produces
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stenosis into the right ventricular outflow tract. The atrialized ventricular chamber is not dilatated and n o paradoxical movement is present. The heart volume is normal o r slightly increased and ECG shows no signs of right atrial hypertrophy. The majority of reports recommend simultaneous closure of the interatrial commtinication (Hardy & Roe, 1968; Kitamura. Johnson. Redington, Mender, Zubiate & Kay, 1971; Jugdutt. Brooks. Sterns, Callagham & Rossall, 1977). Only Lillehei et al. (1967) refrain from this policy. We did not notice any disadvantages of simultaneous closure of this com muni ca t ion. The modality of repair of valvtilar dysfunction is the most controversial problem. Valvulat- reconstruction was recommended by Hunter & Lillehei in 1958 and its practical application and further development were made by Hardy et al. (1964). The essential featiire of this method is transposition of the tricuspid valve to normal position and exclusion of the atrialized part of the right ventricle. Danielson's procedure, which is another variant. employs plicntion of the atrialized ventricle combined with de Vega's reduction annuloplnsty (Mc Faul et a l . . 1976). These procedures seem to give favourable results, but ;ill cases are not resolved in this way (Timmis, Hardy &Watson, 1967). Valvular replacement is the other method for correction of valvular incompetence. Barnard & Schrire (1963) reported the first two successful TVR and recommended fixation of the prosthesis h o v e the coronary sinus to avoid heart block. TVR can be associated with exclusion of the ati-ialized ventricular chamber ( K a y , Tsuji, Redington. Yamada, Kagawa & Kawashima, 1967; Kitamiira et d . . 1971; Jugdutt et a l . , 1977). This exclusion is recommended for aneurysmal dilation and paradoxical movement of this chamber and for improvement of right ventricular filling and pumping. We believe that this method is an unneccessary and somewhat dangerous procedure. We never used this method and its omission has not involved any disadvantages. I t is more important that the prosthetic valve is placed above the atrialized part of the right ventricle. Thereby the negative haemodynamic effect of this chamber on the filling of the functional right ventricle is neutralized. Ostermayer ( 1978) recommends insertion of the prosthetic valve on the atrioventricular ring, above the atrialized part of the right ventricle and usage of cardiac mapping to ,hi ,iiid.I
l l i , ~ ,( ' i i i d i o i
ti\(
\/II.;.
1.1
avoid injury of the bundle of His. We attribute much of the thrombotic malfunction of the tilting disc to the supraprosthetic position of the atrialized ventricular chamber. In such cases. the emptying o f t h e right atrium and filling of the right ventricle are disturbed by this interposed chamber and the stiisis of blood could be due to thrombosis. This is certainly not the only cause of prosthetic thrombosis. a s we have observed it even in tricuspid prosthesises used for other lesions (Peter-ffy. Henze, Jonasson & Bjiirk. 1978). In the rarer form of Ebstein's malformation with tricuspid stenosis, open commissurotomy seems to be a highly recommendable procedure. A minor valvular incompetence after commissurotomy is acceptable. Our experience of tricuspid viilve surgery documents that the ti-icuspid incompetence is well tolerated if the pressure in the piilmonary artery and pulmonar vascular resistance ;ire normal and the left ventricular function is intact. The following conclusions are drawn from our study of Ebstein's anomuly: ( 1 ) Surgical treatment is indicated only in severe forms of malformation and highly individualized surgical tactics are necessary in each ca\e. ( 2 ) Reconstructive procedures give much better resul t s t h ;in palliative ope fiiti oils. (3) Optimal timing of reconstructive surgery is between 15-40 years. (4) Simultaneous closure of the interatrial commu n i ca t i on i nvol v es no d i sad vantages . ( 5 ) Open commissurotomy is ii good method for treatment of the stenotic form. (6) Tricuspid viilve I-eplacement-apart from the valvular I-epair-is a recommendable solution for the typical form of the anomaly with valvular insufficiency. (7) The risk of thrombosis is a questionable indication for B mechanical valve in Ebstein's a n o m d y . However. 2 such patients have no complications 8 and 10 years after TVR, but the percentage of biological valves functioning so long in tricuspid position has not yet been determined. (8) Exclusion of the atrialized part of the right ventricle seems to he less important than the subprosthetic position of this chamber. REFERENCES Adarns, J. C. L. & Hudson, R. 1956 A ca\e of Eh\tein'\ anomaly surviving to the age of 79. Brit Herrrt J 18,
129.
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Siogictil tsc.rrtnicnt of' Ehsteiii's ~ n o r n ~ i l y Barnard, C. N . & Schrire, V. 1963. Surgical correction of Ebstein's malformation with prosthetic tricuspid valve. Sitrgc~ry54. 302. Bialostozky. D., Horowitz. S. & Espino-Vela, J . 1972. Ebstein's malformation of tricuspid valve. A m J C w diol29. 826. Bjork. V . 0. 1978. The improved Bjiirk-Shiley tilting disc valve prosthesis. S c u d J T/iorric, Cardioi~rscSitrg 12. 81. Caipentier, A., Deloche, A., Relland. J.. Fabiani. J. N., Forman, J., Camilleri, J . P.. Soyer, R. & Dubost, Ch. 1974. Six-year follow-up of glutalaldehyde-preserved heterografts. I Thoruc Crirdioi-usc~ Strrg 68. 771, Carwright. R. S., Smeloff. E. A , . Cayler. G. G.. Fong, W. Y . . Huntley, A . C.. Blake, J. R. & McFall. R. A . 1964. Total correction of Ebstein's anomaly by means of tricuspid replacement. J Tliorric, Crirdioiwsc. Siirg 47, 755. Gams, E., Meisner. H., Paek, S. U . & Sebening, F. 1977. Korrektur-Operation bei Morbus Ebstein, Thorcixe/7iritrgie 25, 361. Hardy, K. L., May. I . A , , Webster, C. A . & Kimball, J. G. 1964. Ebstein's anomaly: A functional concept and successful definitive repair. J Thorccc Ctrrdioiwsc Sitrg 48, 927. Hardy, K. L. & Roe. B. B. 1969. Ebstein's anomaly. J Thoruc Ciirdioilusc Sitrg 58, 553. Jugdutt, B. I., Brooks, C. H., Sterns, L. P., Callagham, J. C. & Rossall, R. E. 1977. Surgical treatment of Ebstein's anomaly. J Tl7orcic Curdioivsc Scirg 73, 114. Kay, J. H., Tsuji, H. K., Redington, J. V., Yamada, T., Kagava, Y . & Kawashima, Y . 1967. The sttrgical treatment of Ebstein's malformation with right ventricular aneurysmorrhaphy and replacement of the tricuspid valve with disc valve. Chest 5 / . 537. Kitamura, S., Johnson, 3 . L., Redington, J . V . , Mendez, A . , Zubiate, P & Kay. J. H. 1971. Surgery for Ebstein's anomaly. A m Tlioruc Sirrg I / , 320. Kumar, A . E., Fyler, D. C., Miettinen, 0. S. & Nadas, A. S. 1971. Ebstein's anomaly. A m Curdiol28. 84.
7
Lillehei, C. W., Kalke, B. R. & Carlson, R. G . 1967. Evolution of corrective surgery for Ebstein's anomaly. Circi4lation 35. Suppl. I , 1 1 1. Makous, N. & Vander Veer J . B. 1966. Ebstein's anomaly and life expectancy. Am J Currfiol18. 100. Mannix, E. P. & Berroya. R . B. 1971. Prosthetic replacement of the tricuspid valve for Ebstein's anomaly. J Crirdiotwsc Surg 12, 355. McFaul. R. C., Davis, Z., Giuliani, E. R., Ritter, D. G. & Danielson, G. K . 1976. Ebstein's malformation. J Tltoriic Curdiovusc Sitrg 72, 910. Najafi, H., Hunter, J . A ,, Dye, W. S . , Javid, H. & Julian, 0. C. 1967.Ebstein's malformation of the tricuspid valve. Ann Thoruc Surg4, 334. Ostermeye:, J. 1978. Personal communication. Peterffy, A . , Henze, A , , Jonasson, R. & Bjork, V. 0. 1978. Clinical evaluation of the Bjork-Shiley tilting disc valve in the tricuspid position. Scand J Thorac Cardiovasc Surg. In press. Sealy. W. C., Gallagher, .I.J., Pritchett, E. L. C. & Wallace. A . G. 1978. Surgical treatment of tachyarrhythmias in patients with both an Ebstein anornaly and a Kent bundle. J Tlzorur. Curdiovusc Surg 75, 847. Senoo, Y . , Ohishi, K., Nawa, S., Teramoto. S. & Sunada, T. 1976. Total correction of Ebstein's anomaly by replacement with a biological aortic valve without plication of the atrialized ventricle. J Thoruc Curdiovusc Slrrg 72, 243. Timmis, H. H.. Hardy, J. D. &Watson, D. G. 1967. The surgical management of Ebstein's anomaly. J Thoruc Curdioiwsc Surg 53, 385. Wada, J . , Komatsu, S. & Tanaka, N . 1977. Prosthetic valve surgery in tricuspid area. J Curdiovusc Surg 18. 401. Watson, H. 1974. Natural history of Ebstein's anomaly of tricuspid valve in childhood and adolescence. Br H e m J36. 417.
SURGICAL TREATMENT OF EBSTEIN'S ANOMALY Etirly cind La!i>Results in S ~ ~ ~Cotisrcirtivc e t i Ccises
Arplid Peterffy and Viking Olov Bjork Frori7 the Thorcicic Si4rgic~ilClitiic. KrirolitisAri SjrrXhir.srt. SrocXholni, Swedeti
(Submitted for publication August 14, 1978)
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AhrrLict. The surgical treatment of Ebstein's anomaly is
discussed on the basis of our experience with 7 patients who underwent operation at this clinic during the last ten years. The age of the patients (2 males, 5 females) ranged from 17 to 47 years (mean 27 years) at the time of operation. Two patients were in functional class 11 and five in classes 111 or IV (N.Y.H.A.). The Wolff-Parkinson-White syndrome was Concomitant in 2/7 cases and patent foramen ovale or atrial septal defect (ASD) with right-to-left shunt was present in 6/7 cases. The valvular anomaly was typical in 5 patients and stenosis of displaced tricuspid leaflets into right ventricular outflow region was detected in two patients. Tricuspid valve replacement (TVR) with disc valve prosthesis was performed in 5 patients (BjorkShiley model in 4 cases, Kay-Shiley model in one) and tricuspid valve commissurotomy in two patients. All six patients with interatrial communication underwent closure of this communication simultaneously. One patient had concomitant epicardial mapping and attempted division of the anomalous conduction pathways was unsuccessful. This patient died on the 14th postoperative day from ventricular fibrillation. No other early or late mortality was recorded. Life-long anticoagulation therapy was introduced in all 5 patients with TVR. Thrombotic malfunction of the prosthetic valves necessitated re-operation and new prosthetic valve replacement in two patients 15 and 16 months after the first TVR. One of these patients had recurrent prosthetic thrombosis twice which was successfully treated with streptokinase. The other patient's prosthesis is functioning well 18 months after re-operation. All 6 long-term survivors were impjoved and remained in good condition, in functional class I , I. 3, 3 , 8 , 9. and 10 years, respectively, after operation.
The anatomical characteristic of Ebstein's anomaly is the varying degree of downward displacement of the septal and posterior leaflets of the tricuspid valve with their chordae tendinae and their papillary muscles. The anterior leaflet is usually large and has a normal position. An atrialized right ventricular chamber is interposed between a large right atrium and a small functional ventricular chamber composed of the apical and infundibular parts of the right ventricle. An interatrial communication, either I - 792913
patent foramen ovale o r secundum type defect. is usually present. The functional abnormalities are most often tricuspid incompetence o r more seldom stenosis, low cardiac output due to small ventricular volume and/or interatrial right-to-left shunt. Rhythm disturbances, such as conduction defects (right bundle branch block, pre-excitation), paroxysmal tachycardia and arrhythmia are often concomitant. The atrium and the atrialized part of the right ventricle reveal identical pressures, but their electrical activities and contractions are not synchronized as the atrialized part of the ventricle behaves in this respect as the functional part of the right ventricle. The atrialized part of the right ventricle distends during atrial systole and any contraction of this chamber during atrial diastole only forces the blood back into the atrium (Hardy & Roe, 1969). Ebstein's anomaly has been submitted to reconstructive surgery for the last 15-20 years. The reconstructive procedures are tricuspid valve repair by annuloplasty o r valvular transposition, tricuspid valve replacement (TVR) with o r without exclusion of the atrialized part of the right ventricle and simultaneous closure o r non-closure of the interatrial communication. These methods seem to be much more effective than the palliative shunt operations (Watson, 1974). The indications for surgical treatment and the optimal operative method are still controversial.
CLINICAL MATERIAL This report reviews our experience of corrective surgery for Ebstein's anomaly on the basis of 7 consecutive patients operated on at this clinic during the last 10 years (May 1968 to October 1977). The pre-operative clinical status of our patients is summarized in Table I . There were 2 males and 5 females with a mean age of 27 years
Table I . Prr-opmitivi. c~liriic,rrl.ct(rtrr,s
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RAH = right atrial hypertrophy, RBBB = right bundle branch block. W-P-W atrioventricular block grade I Pat. No.
Functional cia\\
= Wolff-Parkinson-White
Working capacity (W)
Sex
Age (y.)
Clinical signs
1
M
24
Cyanosis, clubbing, cerebral emboli, tachycardiac attacks, systolic murmur
Ill
'5
2
F
27
Cyanosis, clubbing, arterial thrombosis, no heart murmur
Ill
75
3
F
23
Cyanosis, clubbing, arterial thrombosis, syncope, tachycardiac attacks. systolic murmur
IV
32
4
F
17
Cyanosis. clubbing, tachycardiac attacks. systolic and diastolic murmurs
Ill
-
5
M
24
I11
60
6
F
31
Cyanosis, tachycardiac attacks, systolic murmur Atrial fibrillation attacks, systolic and diastolic murmurs
II
I20
7
F
47
II
110
Cyanosis. tachycardiac attacks. systolic murmur
(range 17-47 years) at the time of operation. The mean duration of pre-operative cardiological observation was 20 years. Two patients were in functional class 11, 4 in class I l l and one in class IV ( N . Y . H . A . classification). The heart volume was enlarged in average 761 t 2 6 0 ml/mYBSA and the physical working capacity was decreased in average 70.3k39.2 W. The 6 patients. who had interatrial communication. displayed increased haemoglobin (180.6k32.5 g/l) and haematocrit (55.3+ 11.8%) levels and decreased arterial oxygen saturation (89.l+S.7%) a s the result of the right-to-left shunt. The Wolff-ParkinsonWhite (W-P-W) syndrome was concomitant in 2 cases. he-operative catheterization was performed in 5 patients and cardio-angiography in 6 patients. Results of these investigations are summarized in Table 11.
OPERATIVE FINDINGS AND PROCEDURES Median sternotomy and cardiopulmonary bypass with beating heart were used in all patients and moderate hypothermia (32°C) was added in 3 cases. The malformation was corrected through a right atriotomy. The ascending aorta was cross-clamped during the time of closure of the interatrial communication. The operative findings and procedures are summarized in Table 111. Pronounced valvular incompetence was found in 5 patients and the displaced tricuspid leaflets were stenosed into the right ventricular outflow tract in the remaining two patients. lnteratrial communication was present in 6 cases. Aneurysmal dilatation and paradoxical distension of the atrialized part of the right ventricle were observed in 4 patients.
ECG alteration
\yndrome. AV BI I Heart volume (ml/mLBSA)
RA H RBBB w-P-w RBBB
730
RAH RBBB
700
370
RA H RBBB w-P-w
I 020
RAH RBBB
1 050
RAH RBBB AVBI I RBBB
950
510
Tricuspid valve replacement with low-profile disc valve prostheses was performed in all 5 patients with valvular incompetence. The Bjork-Shiley prosthesis was used in 4 cases and the Kay-Shiley model in one. The tricuspid valve was excised and the prosthesis inserted with mattress sutures. The prosthesis was placed above the coronary sinus on the atrial septum in 3 cases and on the ventricular septum far below the coronary sinus to avoid injury of the bundle of His in 2 cases. No A-V block was recorded postoperatively. On the anterior wall. the prosthesis was fixed to the insertion of the excised anterior leaflet. In patient '6, we attempted to repair the valvular incompetence by performing a d e Vega annuloplasty, but without success. The intra-operative pressure recording revealed that the incompetence had not resolved and tricuspid valve replacement was necessary (Fig. I ) . Tricuspid commissurotomy was performed on the stenosed displaced leaflets into the right ventricular outflow region in 2 patients. The interatrial communication was closed simultaneously in order to prevent paradoxical emboli and t o discontinue the right-to-left shunt in all six patiwts. In patient No. 4, attempted division of the anomalous conduction pathways after epicardial mapping failed as the pre-excitation remained unchanged after operation. No attempts were made to exclude the atrialized right ventricle chamber.
RESULTS Mortcrlily. The o p e r a t i v e m o r t a l i t y wa\ o n e p a t i e n t , No. 4, with c o n c o m i t a n t W-P-W s y n d r o m e a n d in
=
Haemoglobin, g/I Haematocrite. 72
prosthesis was replaced with the new Bjork-Shiley convexo-concave prosthesis (Bjark, 1978). Both patients survived re-operation without complications. The new prosthesis in patient No. 5 thrombosed 12 months after re-operation. On that occasion, the malfunction of the prosthetic valve was successfully treated with streptokinase (Kabikinas:'$). Four months later the anticoagulation ti-eatment was temporarily interrupted in consequence of a traffic accident and the prosthetic malfunction recurred again. The new thrombolytic therapy with streptokinase was successful and the prosthetic valve is now functioning well. F o l l o ~ w p .Follow-up data are avaible on all 6 long-term survivors, 12-125 months (mean 69 months) after surgical correction. The patients were re-examined at this clinic. All 6 were improved, belonged to functional class I without cardiac complaints and are now working. The physical working capacity at the bicycle ergometei- test had increased in average from 70.3k39.2 W to 95.8k28.4 W . This change was not significant. The heart volume in upright position had decreased significantly. Haemoglobin, haematocrit and arterial oxygen saturation had returned to normal levels (Table IV).
Arterial O2 saturation
(76)
''8 72
91
I60 48
91
I90
85
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57 83
I80
60
214 66
85
I38 40
100
156
89
44
whom the intra-operative division of the anom'd I OLlS conduction pathways was unsuccessful. She died on the 14th postoperative day of ventricular fibrillation. No other early or late mortality was recorded. Complicutioris. The major complication was thrombotic malfunction of the prosthetic valves. Thrombotic fixation of the tilting disc in a semiopen position was observed four times in two patients, despite adequate anticoagulation three times, an incidence of 15.2 per 100 patient years. Patients Nos. 4 and 6 were re-operated on 15 and 16 months after the first TVR and the thrombosed
Table 11. Prr-opmiriipe
DISCUSSION The severity of Ebstein's anomaly varies considerably. There are reports of patients who survived over 70 years (Adams & Hudson, 1956; Makous & Van der Veer, 1966). The more serious forms shorten life expectancy considerably (Bialostozky, Horowitz & Espino-Vela, 1972). The prognosis is not so favourable with associated cardiac lesions, more marked cyanosis. extreme cardiomegaly and
c.titlirtrri,7Lition dtitti (rnrnHg) titid
r~.sirltsc!f'ritigioc.Lirdiogrtii~li?'
M=mean pressure, S=systolic pressure, D=diastolic pressure, eD=end-diastolic pressure, R=right, L=left. TI= tricuspid insufficency, Typical=typical Ebstein's malformation. PCV =pulmonary capillary venous pressure Right ventricle
Right atrium Pat. No.
PCV
I 2 3 4 5 6 7
Pulmonary artery
f
Sex M
a-
v-wave
M F F F M F
10
13
7
4 6 4 13 15 N o catheterization N o catheterization 12 14 16 7 1 3 4
S
eD
19
8 8
21 30 22 27
S
D
M
M
19
9
15
-
3
-
-
-
21 20
10
-
11 12
22 22
10
15
13
9
12
9
Direction of shunt
Result of angiocardiography
R-, L Typical, TI R-, L TI k R-, L Typical, TI R-, L Typical, TI N o angiocardiography N o shunt Typical, TI RZL TI Q
+++ ++
+++
+++
4
A . PPtei:ff:v t i t i r l V . 0 . BjjiirX
Table I1 I . Operriti\ie findings, type o f o p i w t i o n
titid
po.stopi'rtitii'i, condition
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K-S = Kay-Shiley prosthetic valve, B-S = Bjork-Shiley prosthetic valve, B-Scc prosthetic valve, F c.=functional class (N.Y.H.A.)
=
Bjork-Shiley
convexcxoncave
Pat. No.
Sex
Age (y.)
Description of valvular lesion
Description of atrialized ventricle
Septa1 defect
Surgical procedure
Fixation of prosthesis
1
M
24
Typical Ebstein, tricuspid insufficency
Aneurysmal dilatation, paradoxical distension
F
27
Slight dilatation, no paradoxical distension
3
F
23
Tricuspid stenosis in right ventricle outflow tract Typical Ebstein, tricuspid insuftiency
Aneurysmal dilatation, paradoxical distension
ASD sec. type
1968.05.02 TVR K-S 8, closure ASD 1969.06.22 open commissurotomy, closure ASD 1970.05.25 TVR B-S 27, closure ASD
Above coronary sinus
2
ASD sec. tY Pe ASD sec. tY Pe
4
F
17
Typical Ebstein, tricuspid insufficency
Aneurysmal dilatation, slight paradoxical distension
ASD sec . type
1970.12.01 TVR B-S 3 I closure ASD
Above coronary sinus
5
M
24
Typical Ebstein, tricuspid insufficency
Aneurysmal dilatation, paradoxical distension
Patent foramen ovale
Below coronary sinus
6
F
31
Typical Ebstein, tricuspid insufficency
Slight dilatation, no paradoxical distension
No
197S.10.21 TVR B-S 3 1 closure foramen ovale 1975.11.05 TVR B-S 31
7
F
47
Tricuspid stenosis in right ventricle outflow tract
Slight dilatation, no paradoxical distension
ASD sec. tY Pe
1977.10.28 open commissurotomy, closure ASD
-
is bad with the appearance of congestive heart failtire (Kumar, Fyler, Miettinen & Nadas, 1971). Our experience and that of others proves that the most favourable timing of the corrective operation is between 15 to 40 years (Cams, Meisner, Paek & Sebening, 1977). Palliative procedures, such as Glenn's anastomosis, can be recommended for in-
-
Above coronary sinus
Below coronary sinus -
fants and very young children who need surgery (Najafi, Hunter, Dye, Javid & Julian, 1967; Mannix & Bert-oya. 1971). Surgical correction seems to be recommendable for patients in funtional classes 111 and IV, patients with sinking cardiac status, moderate to severe cyanosis, paradoxical emboli or arterial thrombosis
Table IV. Pre- rind postoprrcrtii~rc h n g r . s o f 5 diffhnt p(rrrimt~tt~r.s W,,,=maximum working capacity on bicycle ergometer tolerance test, Pre-op. .i=mean value of variable pre-operative, Postop. i = m ean value of variable postoperative, S.D.=standard deviation, d=mean difference, n=number of observations. p=probability level, Sign. =significance Wmtu
Heart volume
(W)
(ml/m' BSA)
Pre-op. .i. S.D.
70.3 k39.2
718
181.0
k 256
k35.4
PostOD.
95.8 k28.4 25.5 6
533 ? I40 - 185 6 0.5
*
Haemoglobin g/l)
**
Haematocri t (%)
Arterial 0, saturation %
54.5 ? 12.7
k5.5
40.5
k9.7 - 14.0 6
10.02
*
90.1 98.8 k0.9 8.7 6 10.01
**
Sirrgicril trrritmrnt of Ehstrin's tinomriiy
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4oommlbp
Postoperative complications
Management of complications
Results Follow-up
No
No
No
No
Good 1Fc. 125 months Good 1Fc. 110 months
No
No
Ventricular fibrillation
Defibrilation
Prosthetic thrombosis, thrombosis x 2. new prosthesis Prosthetic thrombosis
1977.02.I I new TVR B-Scc. thrombolytic treatment x 2 1977.02.17 new TVR B-Scc
Tach ycardiac attacks
Beta blocking agent
5
-
Good I Fc. 99 months Death 14th postop. day Good I Fc. 36 months Good I Fc. 36 months Good I Fc. 12 months
and right ventricular outflow obstruction (McFaul, Davis, Giuliani, Ritter & Danielson, 1976). These criteria were present in our cases. The rhythm disturbances alone do not constitute an operative indication, since they can remain unchangzd after operation, as in one of our patients who also required beta blocking treatment postoperatively. The WP-W syndrome is an exception, in that the cutting through of anomalous conduction pathways could stop the rhythm disturbance (Sealy , Gallagher, Pritohett &Wallace, 1978). In one of our two cases, the pre-excitation disappeared after the operation as a result of the division of these pathways, as in the case reported by Cartwright et al. (1964). In the other case, the epicardial mapping and attempted division were unsuccessful, which could be ascribed to the difficulty of the method and our lack of experience in this field. The optimal surgical correction is not yet defined. This is because personal experience includes less than 10 cases in the majority of reports (Carpentier, Deloche, Relland, Fabiani, Forman, Camillen, Soyer & Dubost, 1974; Wada, Komatsu
0)
Fix. 1 . Intra-operative registration of right atrial ( PR A , mmHg) and right ventricular ( P,(, , mmHg) pressures. The upper part registered after de Vega annuloplasty and the lower part after TVR.
& Tanaka, 1977). On the other hand, the variations of pathology and anatomy make this problem more difficult and nearly every case requires a highly individualized surgical solution (Mannix & Berroya, 1971). Our observations suggest that there are two clearly distinguished clinical and pathological forms of Ebstein's anomaly. One form is the typical displacement of the valvular apparatus with different degrees of tricuspid insufficiency. The aneurysmal dilatation of the atrialized ventricular chamber is secondary to the regurgitation. The paradoxical movement of this chamber is a passive distension of the thin wall during the ventricular systole when blood flows back through the incompetent tricuspid valve. It is not a true paradoxical contraction as McFaul et al. (1976) believed. This assertion is supported by the report by Senno, Ohishi, Nawa, Teramot & Sunada (1976), who observed disappearance of the paradoxical movement after TVR in atrioventricular position. The other form is the obstructive type. In these cases the displaced valvular apparatus produces
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stenosis into the right ventricular outflow tract. The atrialized ventricular chamber is not dilatated and n o paradoxical movement is present. The heart volume is normal o r slightly increased and ECG shows no signs of right atrial hypertrophy. The majority of reports recommend simultaneous closure of the interatrial commtinication (Hardy & Roe, 1968; Kitamura. Johnson. Redington, Mender, Zubiate & Kay, 1971; Jugdutt. Brooks. Sterns, Callagham & Rossall, 1977). Only Lillehei et al. (1967) refrain from this policy. We did not notice any disadvantages of simultaneous closure of this com muni ca t ion. The modality of repair of valvtilar dysfunction is the most controversial problem. Valvulat- reconstruction was recommended by Hunter & Lillehei in 1958 and its practical application and further development were made by Hardy et al. (1964). The essential featiire of this method is transposition of the tricuspid valve to normal position and exclusion of the atrialized part of the right ventricle. Danielson's procedure, which is another variant. employs plicntion of the atrialized ventricle combined with de Vega's reduction annuloplnsty (Mc Faul et a l . . 1976). These procedures seem to give favourable results, but ;ill cases are not resolved in this way (Timmis, Hardy &Watson, 1967). Valvular replacement is the other method for correction of valvular incompetence. Barnard & Schrire (1963) reported the first two successful TVR and recommended fixation of the prosthesis h o v e the coronary sinus to avoid heart block. TVR can be associated with exclusion of the ati-ialized ventricular chamber ( K a y , Tsuji, Redington. Yamada, Kagawa & Kawashima, 1967; Kitamiira et d . . 1971; Jugdutt et a l . , 1977). This exclusion is recommended for aneurysmal dilation and paradoxical movement of this chamber and for improvement of right ventricular filling and pumping. We believe that this method is an unneccessary and somewhat dangerous procedure. We never used this method and its omission has not involved any disadvantages. I t is more important that the prosthetic valve is placed above the atrialized part of the right ventricle. Thereby the negative haemodynamic effect of this chamber on the filling of the functional right ventricle is neutralized. Ostermayer ( 1978) recommends insertion of the prosthetic valve on the atrioventricular ring, above the atrialized part of the right ventricle and usage of cardiac mapping to ,hi ,iiid.I
l l i , ~ ,( ' i i i d i o i
ti\(
\/II.;.
1.1
avoid injury of the bundle of His. We attribute much of the thrombotic malfunction of the tilting disc to the supraprosthetic position of the atrialized ventricular chamber. In such cases. the emptying o f t h e right atrium and filling of the right ventricle are disturbed by this interposed chamber and the stiisis of blood could be due to thrombosis. This is certainly not the only cause of prosthetic thrombosis. a s we have observed it even in tricuspid prosthesises used for other lesions (Peter-ffy. Henze, Jonasson & Bjiirk. 1978). In the rarer form of Ebstein's malformation with tricuspid stenosis, open commissurotomy seems to be a highly recommendable procedure. A minor valvular incompetence after commissurotomy is acceptable. Our experience of tricuspid viilve surgery documents that the ti-icuspid incompetence is well tolerated if the pressure in the piilmonary artery and pulmonar vascular resistance ;ire normal and the left ventricular function is intact. The following conclusions are drawn from our study of Ebstein's anomuly: ( 1 ) Surgical treatment is indicated only in severe forms of malformation and highly individualized surgical tactics are necessary in each ca\e. ( 2 ) Reconstructive procedures give much better resul t s t h ;in palliative ope fiiti oils. (3) Optimal timing of reconstructive surgery is between 15-40 years. (4) Simultaneous closure of the interatrial commu n i ca t i on i nvol v es no d i sad vantages . ( 5 ) Open commissurotomy is ii good method for treatment of the stenotic form. (6) Tricuspid viilve I-eplacement-apart from the valvular I-epair-is a recommendable solution for the typical form of the anomaly with valvular insufficiency. (7) The risk of thrombosis is a questionable indication for B mechanical valve in Ebstein's a n o m d y . However. 2 such patients have no complications 8 and 10 years after TVR, but the percentage of biological valves functioning so long in tricuspid position has not yet been determined. (8) Exclusion of the atrialized part of the right ventricle seems to he less important than the subprosthetic position of this chamber. REFERENCES Adarns, J. C. L. & Hudson, R. 1956 A ca\e of Eh\tein'\ anomaly surviving to the age of 79. Brit Herrrt J 18,
129.
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Siogictil tsc.rrtnicnt of' Ehsteiii's ~ n o r n ~ i l y Barnard, C. N . & Schrire, V. 1963. Surgical correction of Ebstein's malformation with prosthetic tricuspid valve. Sitrgc~ry54. 302. Bialostozky. D., Horowitz. S. & Espino-Vela, J . 1972. Ebstein's malformation of tricuspid valve. A m J C w diol29. 826. Bjork. V . 0. 1978. The improved Bjiirk-Shiley tilting disc valve prosthesis. S c u d J T/iorric, Cardioi~rscSitrg 12. 81. Caipentier, A., Deloche, A., Relland. J.. Fabiani. J. N., Forman, J., Camilleri, J . P.. Soyer, R. & Dubost, Ch. 1974. Six-year follow-up of glutalaldehyde-preserved heterografts. I Thoruc Crirdioi-usc~ Strrg 68. 771, Carwright. R. S., Smeloff. E. A , . Cayler. G. G.. Fong, W. Y . . Huntley, A . C.. Blake, J. R. & McFall. R. A . 1964. Total correction of Ebstein's anomaly by means of tricuspid replacement. J Tliorric, Crirdioiwsc. Siirg 47, 755. Gams, E., Meisner. H., Paek, S. U . & Sebening, F. 1977. Korrektur-Operation bei Morbus Ebstein, Thorcixe/7iritrgie 25, 361. Hardy, K. L., May. I . A , , Webster, C. A . & Kimball, J. G. 1964. Ebstein's anomaly: A functional concept and successful definitive repair. J Thorccc Ctrrdioiwsc Sitrg 48, 927. Hardy, K. L. & Roe. B. B. 1969. Ebstein's anomaly. J Thoruc Ciirdioilusc Sitrg 58, 553. Jugdutt, B. I., Brooks, C. H., Sterns, L. P., Callagham, J. C. & Rossall, R. E. 1977. Surgical treatment of Ebstein's anomaly. J Tl7orcic Curdioivsc Scirg 73, 114. Kay, J. H., Tsuji, H. K., Redington, J. V., Yamada, T., Kagava, Y . & Kawashima, Y . 1967. The sttrgical treatment of Ebstein's malformation with right ventricular aneurysmorrhaphy and replacement of the tricuspid valve with disc valve. Chest 5 / . 537. Kitamura, S., Johnson, 3 . L., Redington, J . V . , Mendez, A . , Zubiate, P & Kay. J. H. 1971. Surgery for Ebstein's anomaly. A m Tlioruc Sirrg I / , 320. Kumar, A . E., Fyler, D. C., Miettinen, 0. S. & Nadas, A. S. 1971. Ebstein's anomaly. A m Curdiol28. 84.
7
Lillehei, C. W., Kalke, B. R. & Carlson, R. G . 1967. Evolution of corrective surgery for Ebstein's anomaly. Circi4lation 35. Suppl. I , 1 1 1. Makous, N. & Vander Veer J . B. 1966. Ebstein's anomaly and life expectancy. Am J Currfiol18. 100. Mannix, E. P. & Berroya. R . B. 1971. Prosthetic replacement of the tricuspid valve for Ebstein's anomaly. J Crirdiotwsc Surg 12, 355. McFaul. R. C., Davis, Z., Giuliani, E. R., Ritter, D. G. & Danielson, G. K . 1976. Ebstein's malformation. J Tltoriic Curdiovusc Sitrg 72, 910. Najafi, H., Hunter, J . A ,, Dye, W. S . , Javid, H. & Julian, 0. C. 1967.Ebstein's malformation of the tricuspid valve. Ann Thoruc Surg4, 334. Ostermeye:, J. 1978. Personal communication. Peterffy, A . , Henze, A , , Jonasson, R. & Bjork, V. 0. 1978. Clinical evaluation of the Bjork-Shiley tilting disc valve in the tricuspid position. Scand J Thorac Cardiovasc Surg. In press. Sealy. W. C., Gallagher, .I.J., Pritchett, E. L. C. & Wallace. A . G. 1978. Surgical treatment of tachyarrhythmias in patients with both an Ebstein anornaly and a Kent bundle. J Tlzorur. Curdiovusc Surg 75, 847. Senoo, Y . , Ohishi, K., Nawa, S., Teramoto. S. & Sunada, T. 1976. Total correction of Ebstein's anomaly by replacement with a biological aortic valve without plication of the atrialized ventricle. J Thoruc Curdiovusc Slrrg 72, 243. Timmis, H. H.. Hardy, J. D. &Watson, D. G. 1967. The surgical management of Ebstein's anomaly. J Thoruc Curdioiwsc Surg 53, 385. Wada, J . , Komatsu, S. & Tanaka, N . 1977. Prosthetic valve surgery in tricuspid area. J Curdiovusc Surg 18. 401. Watson, H. 1974. Natural history of Ebstein's anomaly of tricuspid valve in childhood and adolescence. Br H e m J36. 417.
