Echinococcosis of the heart

Echinococcosis of the heart Report of three new cases H. Romanoff, M.D., F.A.C.S., Jerusalem, Israel

The cardiac localization of an Echinococcus cyst is a rare occurrence. It has been observed in areas where hydatid disease is endemic. In 1962, Milwidsky and P reported a case of primary cardiac echinococcosis and reviewed the available literature. Individual surgical cases of cardiac echinococcosis continue to be reported. In a recent review of the world literature, Heyat and colleagues" added 75 cases to the 43 included in our study. In the following, I wish to present 3 additional cases of cardiac echinococcosis in which surgical treatment was successful. Case reports CASE 1. K. S., a 35-year-old man who was born in India, immigrated to this country I year before his admission to the hospital. Routine xray study of the chest revealed a calcified mass in the area of the apex of the heart, and the patient was referred on June 9, 1964. On admission, there were no complaints. The patient was thin, short, and weighed 46 kilograms. The blood pressure was 120/80 mm. Hg, and the pulse rate was 84 beats per minute and regular. On physical examination, the heart was not enlarged. The apex beat, which was diffuse, was palpable 2 ern. lateral to the mid clavicular line in the fifth intercostal space. The heart sounds were normal on auscultation, and no murmurs were heard. The x-ray film of the chest showed an egg-shaped mass, calcified at its periphery, protruding slightly at the apex (Fig. I). The electrocardiogram showed the following: 'There is sinus

From the Thoracic and Vascular Surgery Unit, Hadassah University Hospital. Jerusalem, Israel. Received for publication Jan. 2, 1973.

rhythm with left axis deviation. Symmetrical, deeply inverted T waves are noted in Leads II, III, aV.·, and V, to V•. There is a lack of progression of R waves in chest leads. A positive T wave is seen in a V R. These findings indicate inferolateral myocardial damage" (Dr. Basil Golding) (Fig. 2). Routine laboratory examinations were normal. The Casoni skin test was positive, and the Weinberg agglutination test was negative. The diagnosis of left ventricular hydatid cyst was strongly suspected, and the patient was operated upon on June 25, 1964. A left anterolateral thoracotomy was performed through the fifth rib bed. After retraction of the lung, a cyst-like tumor, measuring 7 by 5 ern. with a horizontal axis, was immediately seen on the lateral, posterior, and inferior aspects of the left ventricle. As the pericardium was strongly adherent to the cyst, it was opened to the right of the phrenic nerve. The cyst was implanted in the posterior and lateral walls of the left ventricle. The operative finding was consistent with the electrocardiogram, showing involvement of the inferolateral myocardium. Calcifications were present over the entire cyst wall except at the apex, where the mass was soft and pulsating. The cyst was tapped and, as no fluid could be aspirated, it was incised longitudinally. An amorphous, puriform, brown material formed the content of the cyst. The redundant peri cyst was widely excised, thus unroofing the cyst. After removal of the amorphous material, old blood clots were found at the depth suggesting that bleeding had occurred in the cyst cavity by penetration of the left ventricle cavity. As soon as an attempt was made to remove the clots, brisk bleeding occurred at the depth from a 3 mm. hole in the ventricular cavity. This was easily controlled with a few silk sutures. The weak area in the left ventricle was reinforced by bringing the remaining pericyst over it and approximating the free edges. The pericardium was also sutured to the area but otherwise was left

29

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Thorocic ond Cordiovosculor Surgery

Fig. 1. Patient K. S. A , Posteroanterior view of calcified mass seen at apex of heart. B. Lateral view. Note the calcified rim. partially open . The chest was closed in layer s, with an underwater seal drain connected to a mild suction apparatus. The content of the cyst was sterile on bac teriologic examin ation. "Histologic examination shows the wall of the cyst to be composed of acellula r collagenous tissue with lar ge areas of calc ification. Occasion al agg regate s of chro nic inflamm atory cells and deposits of hemosiderin are pre sent with in this tissue. Attached to the inner wall of the cyst is amorphous eosinophilic material with no signs of organization . The exact nature of the cyst is not clear from the histologic findings" (Professor Martin Sack s ) . Although no hydatic remn ant s were seen, the diagnosis of dead involuted hydatic cyst of the he art was nonetheless evident , based on the calcification of the cyst wall and the well-known amorphous degene rative mat er ial found in such instances. The postoperative course of the patient was uneventful, and he was disch arged on the twent ysixth day after the operation . The postoperative electrocardiogram showed the following: "There is sinus rhythm with a ventricular premature beat seen in Lead V,. In addit ion to the findin gs mentioned in the preoperative electrocardiogram , there is now an inverted T wave in Leads I and V" as well as flat T waves in Leads a Vr, and V," ( D r. Basil Gold ing ) ( F ig. 3) . The pati ent is known to be working and well 8 yea rs later.

CAS E 2. P. S., a 24-year-old woman who was born in Israel, complained of mild pain in the left chest and axilla which increased on deep inspiration. The x-ra y film of the chest showed a localized deformat ion of the left heart border, and the patient was referred on May 8, 1966. On admission, she was in excellent general condition. The blood pressure was I 10170 mm. Hg, and the pulse rate was 80 beats per minute and regula r. On ph ysical examination, the heart was not enlarged. The heart sounds were normal on auscultation, and no murmurs were heard. The x-ray film of the chest showed a round bulging mass at the left heart border above the apex (F ig. 4, A ) , and the lateral film showed a homogeneous opacification o ver the heart shado w, with well-delineated borders ( Fig. 4, B) . Plan igrams sho wed that the mass was intimately adherent to the heart border. At fluoroscop y, the mas s actually pulsated simulta neously with the heart. Ang iocardiography disclosed that there was no bulging de fect into the left ventricular cavity . The electrocardiogram showed the following: "There is sinus bradycardia with a vertical heart. Deep, inverted, symm etrical T waves are seen in Leads I, aV I . , and V , to V", with a biphasic T wave in V,. A positive T wave is seen in Lead a V H • Deep but not widened Q waves are seen in Leads V, and V". These findings suggest involvement of the anterior myocardium" (Dr. Basil Golding ) (F ig. 5) . Routine laboratory examinations were normal.

Volume 66

Echinococcosis of heart

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July, 1973

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"This means 11 mm./l hour and 30 mm./2 hours.

coccus cyst of the left ventricle was nevertheless suspected on the bases of the x-ray findings and the electrocardiographic changes. The patient was operated upon on May 11, 1966. With cardiopulmonary bypass available, a left anterolateral thoracotomy was done through the fourth rib bed, and the left common femoral artery was simultaneously exposed in the groin. The lung

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Thorac ic and Card iovascular Surgery

Fig. 4. Patient P. S. A, Posteroanterior view shows bulging at left heart border. B, Lateral view shows opacity over heart shadow. was retracted , exposing an egg-shaped tumor with two bulges , the distal one having the large st diameter. The pericardium, with the phrenic nerve, was densely adherent to the mass. It was widely opened longitudinally to the right a nd to the left of the mass. The cyst was implanted in the wall of the left ventricle over a wide area. It extended from the atrioventricular groove to the apex longitudinally and from the anterior descending branch of the left coronary vessel to the lateral and posterior aspects of the left ventricle. It measured 10 by 6 cm. and had apparently eroded into the myocardium and possibly down to the endocardium. The operative finding was cons istent with the electrocard iogram, showing involvement of the anterior myocardium. It was believed that opening the cyst at this stage might provoke a major hemorrhage, and prep arat ions were therefore made for cardiopulmonary bypass. The thoracotomy incisio n was lengthened anteriorly, the sternum was tran sected, and , after administration of heparin, the right atrium and the left common femoral artery were cannulated . As the cardiopulmonary bypa ss machine was ready, the pericardium was freed from the mass , and the largest cyst was tapped. Since no fluid or blood could be aspirated, the needle was removed and a thick yellowish fluid appeared at the puncture hole. The cyst was now widely incised longitudinally. It was filled with a yellow,

thick, amo rphous puriform material, and mult iple debri s of characteristics membranes of dead para· sites were found among the contents, therefore confirming the diagnosis of cardiac ech inococcosis . The redundant fibrotic cyst was resected in order to expose the cavity. All degenerated material was removed, a nd the cyst cavity was throughly washed with saline solution. Myocardial tissue could still be recognized and palpated in the depth of the cavity. The pericyst edges were approximated with interrupted silk sutures in order to reinforce the weak point in the ventricular wall. The atri al and left femoral cannulas were removed, and protamine sulfate was adm inistered . There had been no need for the heart-lung rnachine. The pericardium was left open and the chest closed , with an underwater seal dra in connected to a mild suctio n apparatus. The content of the cyst was sterile on bacteriologic examination. "T he material removed at surgery consisted of fra gments of whitish membranes structures. The histologic features of the membranes were consistent with a hydatic cyst" (Dr. Eliezer Rosenmann ) . The postoperative course of the patient was uneventful, and she was discharged on the nineteenth day after the operation. The postoperative electrocardiogram showed the following : "T he electrocardiogram is similar to the preoperative tracing except for inverted T waves in

Volu me 66

Echinococcosis of heart

Nu mber 1

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Fig. 6. Patie nt P. S. Postoperative electrocardiogram , taken May 27, 1966. Leads II , aV.·, and V" with a diphasic T wave in Lead III" (Dr. Basil Gold ing ) (F ig. 6) . The patient is known to be working and well 5 years later. CA SE 3. Y. Y., a 24-year-old woman who was born in Iraq and immigrated to this country at the age of 4 years, complained of a productive

cough of about 6 months' duration. X-ray examination of the chest showed a markedly enlarged left ventricle , and the patient was referred on Feb. 14, 1971. On admission, she was in excellent condition. The blood pressure was 130/80 mm. Hg, and the pulse rate was 88 beats per minute and regular.

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Thoracic and Card iova scular Surgery

Fig. 7. Patient Y. Y. Posteroanterior chest x-ray film shows aneurysm-like contour of left heart border.

Fig. 9. Patient Y. Y. Lateral planigram shows round shadow over the heart.

Fig. 8. Patient Y. Y. Posteroanterior planigram shows deformed contour of left heart border. The apex beat was palpable at the fifth intercostal space in the midclavicular line. A Grade 2/6 systolic murmur could be heard over the left second intercostal space. A posteroanterior chest x-ray film (Fig. 7) and planigram (F ig. 8) showed an aneurysm-like contour of the left hea rt border. A lateral planigram disclosed a well-

delineated round shadow over the heart (Fig. 9). The electrocardiogram showed the following: "There is sinus rhythm with right axis deviation. Abnormal Q waves are seen in Leads I, aVL, V" and V•. There is slight S-T elevation as well as deep, symmetrical T-wave invers ion in Leads I, aVL, V., V" and Vo. A positive T wave is seen in Lead aV R. These findings are consistent with anterolateral myocardial damage" (Dr. Basil Golding) (Fig. 10). Routine laboratory examinations were normal. The erythrocyte sedimentation rate was 20 mm. The erythrocyte sedimentation rate was 20 mm.! 45 mm. * (We stergren ). Culture of the sputum revealed normal flora. The Casoni test was not done for technical reasons . Exploration was advised, and a left lateral thoracotomy through the sixth rib bed was performed on Feb. 18, 1971. The lung was retracted to expose a cyst-like tumor, measuring 10 by 8 crn., that covered most of the left ventricle as far as 2 em . to the right of the phrenic ner ve and extended from the origin of the pulmonary artery down to the apex. The mass was covered with a strongly adherent per icardium . The lesion was soft, but it hardened with each myocardial contr action. The surrounding mediastinal pleura was markedly edematous and inflammatory. The operative finding was consistent with the "T his means 20 mm ./l hour and 45 mm ./2 hours .

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Fig. 10. Pat ient Y . Y. Pr eo perative electrocardiogram, tak en F eb. 17, 1971. F indi ngs are consistent with anterolateral myocardial dam age . electroca rdiographic localization of the lesio n in the an terolate ral myo cardium . The natu re of the cystic mass was stro ngly suspected to be an Echinococcus cyst. Therefore, the cyst was tapped. As no fluid or blood could be aspirated, it was punctured with a No. 15 knife blade . The diagnosis became immediately obvious as a yel lowish amorphous material appeared through the hole. The incision was lengthened for anot her 2 em. The cyst cavity was found to be filled with a yellow degenerative granular material. The pericyst consisted of pericardium which was 3 mrn . thi ck. T wo flat hydatid membranes, one of which was smaIl, were fou nd in the cyst. Th e incision in the pericardium was further lengt hened proximaIly , and calcified areas were noted in the pericyst pericardium . The cyst ca vity measured 8 em . in diameter. The myocardium was covered with a layer of fibrin and degenerative material which could be easily removed. The redundant peri cyst or pericardial layer was excised, and the cyst ca vity was thoroughly washed with saline solution . The edges of the per icyst were now approximated, a 2 ern. opening being left for drainage. Th e thoracotomy incisio n was closed in layers, with an underwater sea l drain att ach ed to mild suction . The Casoni test, which could now be per formed postoperatively, was positive ( 10 by 8 em .) . The content of the cyst was sterile on bacteriologic examinat ion. "The specimen consisted of a collapsed and empty cyst , 7 em . in diameter. The wa ll con sisted

of soft whit ish tissue . The inner lining showed a fine granularity and a brownish discoloration. A smear taken from the cyst lining showed numerous cholesterol crystals but no hydatid hooklets or scolices. Histo logic sections from the cyst wall showed the typical lam inated appearance of hydatid ectocyst" (Professor Martin Sacks) . The postoperative course was uneventful, and the patient was discharged on the twelfth postoperative da y. " In comparison with the preoperative electrocardiogram, there is flattening of the T waves in Leads II, III, aV .., V" V" V" and V'" ( Dr. Basil Go lding ) (Fig. 11) . At present, 11/ 2 years after the operation, the patient is working and wel l.

Dis cussion

Hydatid disease is prevalent in this part of the world. " Apart from those infested patients born in this country, many others have immigrated from countries where the disease is endemic. The main reason for infestation is to be found in the lack of adequate supervisio n of animal slaughtering and the presence of a great number of stray dogs harboring the adult worm." Cardiac echinococcosis has been reported by others in this country. Better and coworkers: reported 3 autopsy cases in 1963. In 1969, Deutsch and colleagues> reported

The Journal of

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Romanoff

Thoracic and Cardiovascular Surgery

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the case of a 16-year-old patient who was operated upon successfully in 1965. The same patient was operated upon again in 1969. n Two other patients had been registered at their hospital." The studies of Deve," Dew,' and some South American authors," 10 from Uruguay particularly, have added much to our knowledge of this disease. Cardiac echinococcosis has recently been reviewed by Murphy and associates" from the United States, Ramos and colleagues'> from Spain (quoting the important Spanish language contributions to the subject), Papamichael's group!" from Greece, and Heyat and co-workers- from Iran. The incidence of cardiac echinococcosis is estimated to be about 2 per cent of total infested cases,12,14 the wall of the left ventricle being involved in 60 per cent." The primary cardiac cyst results from the implantation of the embryo hexacanth into the myocardium. The larva reaches the heart via the coronary circulation after its passage through the liver and lung circulations. Other routes are possible as well. 2 The embryo might reach the heart through the lymphatics of the bowel, the thoracic canal, and the superior vena cava or else

through the large bowel, the hemorrhoidal veins, and the inferior vena cava. Another possible route is through the aspiration of the egg of the tenia and its subsequent passage through the pulmonary veins. '5 The primary cyst is solitary unless a multiple infestation has occurred, which is not impossible." Dew" recognized five stages in the development of the cardiac cyst. In the first stage, the univesicular cyst becomes implanted in the myocardium. In the second stage, the cyst ruptures either into a cardiac chamber, causing sudden death by anaphylaxis, or into the pericardium, with formation of a single or multiple pericardial cysts. In the third stage, multiple secondary cysts begin to grow either in the pericardium or in various other parts of the body; this latter possibility, however, is quite rare.!" In the fourth stage, following rupture, the myocardial cyst may be dead or may reform itself; in the latter instance, it will contain multiple daughter cysts," including multiple systemic and pulmonary cysts." In the fifth stage, the reformed secondary pericardial or intramural cyst may rupture in a cardiac chamber causing death from anaphylaxis or embolization of daughter cysts.t"- 17

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Echinococcosis of heart

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July, 1973

In addition to intracardiac or intrapericardial rupture, rupture into the myocardium itself, with formation of local secondary echinococcosis, has been recognized." Spontaneous involution of the cyst is also possible, with subsequent hyaline degeneration of its content, calcification, and inflammatory reaction of the neighboring tissues." Our Case 1 probably illustrates this possibility. When several cysts are found, they are considered to be secondary cysts" that originated either from a ruptured primary myocardial cyst or from a ruptured cyst of the liver, lung, or mediastinum, the fertile elements reaching the heart through the venous circulation. ell Our Case 2 probably illustrates this possibility, as a secondary myocardial cyst originated from the rupture of a primary cardiac cyst. Pericardial echinococcosis, in addition to originating from a ruptured myocardial cyst, might also develop, although rarely, from a ruptured pulmonary or mediastinal cyst." Diverse forms of pericardial involvement have been described,"- 13 among others, an acute form of hydatid pericarditis. ar The lesion in Case 3 assumedly resulted from a ruptured myocardial cyst. The symptomatology of cardiac echinococcosis is poor. There is usually a long period with no indications of disease. Dyspnea at effort, cough, and precordial pain have been noted." The electrocardiographic changes are most valuable signs and have been described in detail by several authors." le. 11. ee Inverted T waves of coronary type in Leads I and aV L and in the precordial left leads are noted. It has been stated that a deep inversion of the T wave means that a rather thin myocardial layer is present beneath the cyst. 12 In addition, positive T waves in Lead aV n and the absence of Q waves are noted.'> A small R wave is present in cases in which the cyst is large and a thin myocardial layer remains. There is no displacement of the S-T segment."· 12 With help from the electrocardiogram, Larguero'" was able to localize quite accurately the area of implantation of

the cyst into the myocardium and evaluate the thickness of the residual myocardial layer between the cyst and the heart chamber. The electrocardiographic changes usually have remained unchanged after the operation or have regressed very slowly. 24 The presence of a hydatid cyst produces a deformation of the heart contour on radiologic examination. Characteristically, there is an opacity over the left ventricular border in the area of the apex, with a more accentuated density. Calcification seen in the area of the cyst facilitates the diagnosis. Abnormal pulsations might be seen at fluoroscopy." It is possible for echinococcosis of the heart to simulate a cardiac aneurysm." Defects in a cardiac chamber have occasionally been seen at angiocardiography." Negative biological reactions should not exclude the diagnosis of cardiac echinococcosis when the disease is suspected." As severe and often fatal complications have frequently occurred after the rupture of an untreated myocardial hydatid cyst, early surgical intervention has been advocated.]·11 The first surgical intervention was attempted by Marten and De Crespigny" in Australia in 1921, and the first successful intervention was reported by Long," also in Australia, in 1932. The procedure consists of removal of the cyst. If the parasite is living, it should be first sterilized by injection of formalin, ether, or a 33 per cent sodium chloride solution into the cyst." The cyst bed is also spread with the sodium chloride solution,' and the pericyst is resected either completely or partially. In partial resection, it can either be left open or resutured with a reinforcing suture of the pericardium, all depending upon the depth of implantation of the cyst into the myocardium." The use of cardiopulmonary bypass has been advocated in the management of cardiac cysts in cases in which the risk of hemorrhage is great or the cyst is localized in the interauricular or interventricular septum." Cardiopulmonary bypass apparently was used first by Artucio ' ° in 1961 in the surgical management of cardiac

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Romanoff

Thoracic ond Cardiovascular Surgery

echinococcosis. Murphy's group!' was the first to use it in the United States. With surgical therapy, cure is possible in this otherwise severe infestation. Many more cases are expected to be successfully managed.

10

Summary

Following the previously reported case of primary echinococcosis of the heart, 3 additional cases are now reported. All 3 patients were successfully operated upon. The development, natural history, diagnosis, and surgical therapy of cardiac echinococcosis are reviewed. I am grateful to Dr. Basil Golding of the Cardiology Service, Hadassah University Hospital, for reviewing the electrocardiograms, and to Professor Martin Sacks and Dr. Eliezer Rosenmann of the Department of Pathology, Hebrew University Hadassah Medical School, for the pathologic reports.

11

12

13 14

15 REFERENCES

2

3 4

5

6

7

8

9

Romanoff, H., and Milwidsky, H.: Primary Echinococcosis of the Heart Cured by Operation, J. THoRAc. CARDIOVASC. SURG. 43: 677, 1962. Heyat, J., Mokhtari, H., Hajaliloo, J., and Shakibi, J. G.: Surgical Treatment of Echinococcal Cyst of the Heart, J. THORAc. CARDIOVASCo SURG. 61: 755, 1971. Frayha, G. J.: Studies on Hydatid Disease in Lebanon, Leb. Med. J. 23: 135, 1970. Better, 0., Griffel, B., and Brandstaetter, S.: Myocardial Echinococcosis, Harefuah 64: 323, 1963. Deutsch, V., Kreisler, B., Padeh, B., and Pausner, Y. M.: Echinococcosis of the Heart Diagnosed by Cardioangiography, Br. J. Radiol. 42: 540, 1969. Behar, S., Kreisler, B., and Kariv, I.: Echinococcosis of the Heart With Ventricular Tachycardia, Harefuah 81: 68, 1971. Deve, P.: Les kystes hydatiques du Coeur et leurs complications, Algerie med. 32: 179, 1928. Quoted by Ramos et al. 12 Dew, H. R.: Hydatid Disease, Australasian Medical Publishing Company, 1928. Quoted by Gibson, D. S,17 Canabal, E. J., Aguirre, C. V., Dighiero, J., Purealias, J., Baldomir, J. M., and Suzacq, C. V.: Echinococcus Disease of the Left Ventricle.

16 17 18 19

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23

A Clinical, Radiologic and Electrocardiographic Study, Circulation 12: 520, 1955. Artucio, H., Reglia, J. L., Di Bello, R., Dubra, J., Gorlero, A., Polero, J., and Artucio Urioste, H.: Hydatid Cyst of the Innerventricular Septum of the Heart Ruptured Into the Right Ventricle: First Case in the World Literature Diagnosed and Successfully Operated Upon With Open Heart Surgery, J. THoRAc. CARDIOVASC. SURG. 44: 110, 1962. Murphy, T. E., Kean, B. H., Venturini, A, and Lillehei, C. W.: Echinococcus Cyst of the Left Ventricle: Report of a Case With Review of the Pertinent Literature, J. THoRAC. CARDIOVASC. SURG. 61: 443, 1971. Ramos, G., Villar, J. L. del, Sainz, J. L., Busto, E. F., del Gonzalez, E., and Ortega, J.: Hidatidosis cardiaca, Rev. Clin. Esp. 121: 411, 1971. Papamichael, E., Ikkos, D., Milingos, M., and Yannacopoulos, J.: Echinococcosis of the Heart, Chest 59: 280, 1971. Arcos, E. de Cos, Madurga, M. P., Perez, L. J., Martinez, J. L., and Urquia, M.: Hydatid Cyst of Interventricular Septum Causing Left Anterior Hemiblock, Br. Heart J. 33: 623, 1971. De la Fuente Chaos, A.: Patologica quirurgica. Torno III. Segunda parte. Cirurgia del Corazon, grandes vasos y mediastino, Edit. Cientif. Med. Madrid, 1964. Quoted by Ramos et al,12 McConchie, I.: Cardiac Hydatid Disease, Aust. N. Z. J. Surg. 34: 18, 1964. Gibson, D. S.: Cardiac Hydatid Cysts, Thorax 19: 151, 1964. Ivanissevich, 0., and Rivas, C. I.: Equinococosis hidatidica, Tall. Graf. Minist. Educ. Just. Buenos Aires, 1962. Quoted by Ramos et al. 12 Rodriguez Rebollo, A, and Mugica Echarte, J.: Un caso de quiste hidatidico de la pared ventricular izquierda, Rev. Esp. Cardiol. 19: 750, 1963. Quoted by Ramos et al. 12 Peters, J. H., Dexter. L., and Weiss, S.: Clinical and Theoretical Considerations of Involvement of the Left Side of the Heart With Echinococcal Cyst, Am. Heart J. 29: 143, 1945. Di Bello, R., Mantero, M. E., Dubra, J., and Sinjanes, A: Hydatid Cyst of the Left Ventricle of the Heart: Acute Hydatid Pericarditis, Am. J. Cardiol. 19: 603, 1967. Dighiero, J., Canabal, E. J., Aguirre, C. V., Hazan, J., and Horjales, J. 0.: Echinococcus Disease of the Heart, Circulation 17: 127, 1958. Larguero, I. P.: Tratamiento del quiste hidadico del ventriculo izquierdo, Torax 3: 263, 1954. Quoted by Ramos et al. 12

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July, 1973

24 Piaggio Bianco, R. A., Dighiero, J., Canabal, E. J., Baldomir, J. M., Aguirre, C. V., Purcallas, J., and Suzacq, C. V.: Quiste hidatico cerrado del ventriculo izquierdo. Superfil eIectrocardiographico, An. Fac. Med. Montev. 38: 310, 1952. Quoted by Ramos et alY 25 Di Bello, R., Rubio, R., Dighiero, J., Zubiaurre, L., and Cortes, R.: Pseudoaneurysmatic Form of Cardiac Echinococcosis: Report of

a New Case and Review of the Literature, J. 45: 657, 1963. 26 Marten, R. H., and De Crespigny, C. T. C.: Notes on a Case of Hydatid Cyst of the Heart, Med. J. Aust. 8: 287, 1921. Quoted by Gibson.'; 27 Long, W. J.: Hydatid Disease in the Left Ventricular Wall of the Heart, Med. J. Aust, 19: 701,1932. Quoted by Gibson.'; THORAC. CARDIOVASC. SURG.