Asian Cardiovasc Thorac Ann 2003;11:160-162
© 2003 Asia Publishing EXchange Ltd
Right Intraventricular Hydatid Cyst of the Heart
Rasheed A Saad, MRCS1,
Khalid MA Amer, FRCS,
Marcello Migliore, FETCS1,
Tarek Aziz, FRCS1,
Ahmed Azzu, FRCS
Department of Cardiothoracic Surgery, University Hospital of Wales, Cardiff, Wales, UK
1 Cardiopulmonary Transplant Unit, Department of Cardiothoracic Surgery, Freeman Hospital, Newcastle upon Tyne, England, UK
For reprint information contact: Ahmed Azzu, FRCS Tel: 44 2920 742 944 Fax: 44 2920 745 439 email: ahmed.azzu{at}uhw-tr.wales.nhs.uk Department of Cardiothoracic Surgery, University Hospital of Wales, Heath Park, Cardiff CF14 4XW, UK.
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ABSTRACT
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A 32-year-old woman presented with shortness of breath and palpitations. Echocardiography and contrast-enhanced computed tomography showed a 4 x 5 cm cyst in the apex of the right ventricle. The cyst was excised on cardiopulmonary bypass. The patient made an uneventful recovery. At the one-year follow-up, she was symptom-free and without recurrence. Different clinical aspects of cardiac hydatid cyst and its surgical management are reviewed.
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INTRODUCTION
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Hydatid disease is a parasitic infection that is endemic in certain parts of the world. Cardiac involvement is rare, with an incidence of 0.5% to 2%.1 Exposure to dogs in endemic regions is a consistent finding in such patients. Contrast-enhanced computed tomography (CT) is useful in defining the lesion and detecting the presence of multiple lesions at different sites.2 Surgical treatment of cardiac hydatid disease was first attempted in 1921,3 while the first successful excision of a cardiac hydatid cyst was executed in 1932.4
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CASE REPORT
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A 32-year-old woman was admitted to the cardiology unit of a general hospital with a 4-month history of progressive dyspnea and occasional brief episodes of palpitations. The dyspnea was precipitated by minimal exertion (New York Heart Association functional class III). She lived in a rural community all her life, never smoked, and had no past medical history of note.
On examination, she was in sinus rhythm of 80 beats•min-1, blood pressure was 110/70 mm Hg, and respiratory rate at rest was 15 breaths•min-1. Systemic physical examination was unremarkable. Routine hematological and biochemical investigations were normal, as well as the chest radiograph and electrocardiogram. Transthoracic and subsequently transesophageal echocardiography showed no abnormal features except a large cyst, 5 cm in diameter, in the cavity of the right ventricle that appeared to be attached to the ventricular septum (Figure 1
). CT scan of the chest and abdomen showed a 4 x 5 cm cyst in the right ventricle with no other lesions.
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Figure 1. Transesophageal echocardiogram showing the cyst in the right ventricle. LA = left atrium, LV = left ventricle, RA = right atrium, RV = right ventricle.
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The diagnosis of cardiac echinococcosis was made on clinical grounds since the patient lived in a rural area where sheep farming was common and hydatid disease was known to be endemic. Serological screening for echinococcosis by enzyme-linked immunosorbent assay (ELISA) was negative. The patient was then transferred to the regional cardiothoracic unit for further management.
At our unit, decision was made to excise the cyst. A midline sternotomy was made, and cardiopulmonary bypass (CPB) was established utilizing bicaval venous cannulation and arterial return via the aortic root. Cold blood cardioplegia was infused through the aortic root, and the same cannula was used to vent the left ventricle. The right ventricle was carefully opened over an avascular area parallel to the left anterior descending artery, applying the scalpel in short strokes to avoid breaching the cyst wall. The cyst was found to occupy the apical part of the right ventricle (Figure 2), attached to the ventricular septum by fine trabeculae as shown in the preoperative echocardiogram. The conduction system of the heart was seen to be at a safe distance away. Sharp dissection was initially used to divide the trabeculae. Blunt dissection was then employed to enucleate the cyst en bloc, leaving behind a healthy myocardium. During excision of the cyst, there was no change in the perfusion pressure of CPB. The right ventricle was then closed and the patient weaned off CPB without inotropic support. The total duration of CPB was 38 minutes and crossclamp time was 25 minutes.
The patient’s postoperative course was uneventful. She was extubated 6 hours after the operation and discharged home 5 days later with a 3-month course of albendazole (400 mg twice daily). She was advised to treat pet dogs in the household with an anti-tapeworm agent such as praziquantel. Histological examination of the cyst showed classical features of a hydatid cyst with intact layers, confirming complete excision. At the one-year follow-up, the patient was asymptomatic with no evidence of recurrence.
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DISCUSSION
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Human hydatidosis is typically due to infection with the canine tapeworm Echinococcus granulosus. Less common species infecting man are Echinococcus multilocularis and Echinococcus vogeli. Infection arises from handling dogs with contaminated hair or ingesting contaminated vegetables.
Cardiac hydatidosis is uncommon, with the left ventricle being the most common site, accounting for 77% of all cases of cardiac hydatidosis, while the left atrium is the least affected site with an incidence of 3.7%.1 The incidence in the right ventricle, as in our case, is 11.5%.
The clinical picture of cardiac echinococcosis is dependent on the location of the cyst and its degree of interference with the function of the surrounding structures. It can act as a space-occupying lesion causing low cardiac output, ventricular outflow obstruction, or constrictive pericarditis. Interventricular septal infection may present as a conduction defect. Cardiac hydatidosis may present with nonspecific features such as weight loss, dyspnea, and fever.1 The presentation can be more dramatic if the cyst ruptures, resulting in anaphylactic shock and/or thromboembolism.5,6 In our case, the dyspnea was most probably secondary to reduced pulmonary blood flow, while the palpitations could have been due to irritation to the conducting fibers in the ventricular septum. The disease should be suspected in patients from sheep-farming areas who present with nonspecific cardiac symptoms.
The ELISA test for hydatid disease has a sensitivity of 91% and specificity of 82%.7 In our patient, the test was negative, making it difficult to confirm the preoperative diagnosis. Two-dimensional echocardiography is the investigation of choice in the diagnosis of cardiac hydatidosis.8 The CT scan in this case correlated with echocardiographic findings. Furthermore, it allowed us to delineate the anatomical relationship and exclude the presence of multifocal disease.
Surgical treatment is the only option for cardiac hydatid disease since medical therapy does not offer insurance against rupture of the cyst and its potential complications.5,6 Resection of an intracardiac cyst is recommended to avoid the grave complication of rupture, which is as common as 39%.5 A right ventricular approach was chosen in our case over a right atrial approach because of the size of the cyst and the degree of dissection and cyst mobilization. The cyst was floating in the right ventricle, so there was no pericystic host layer. Extreme care was taken during enucleation to avoid damaging the thin layer of cyst wall. Sterilization of the cyst content before manual handling using 2% formalin or hypertonic saline solution has been advocated.6 During excision, it is important to avoid spilling the cyst content, which may trigger an anaphylactic reaction. Reported results of surgical resection have been very encouraging with low mortality.8
Patients should be advised to develop veterinary control where animal husbandry is common and to pretreat pet dogs with anti-tapeworm agents in order to reduce the incidence of the disease.
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REFERENCES
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- Long WJ. Hydatid disease in left ventricular wall of the heart. Med J Aust
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- Poretti D, Felleisen E, Grimm F, Pfister M, Teuscher F, Zuercher C, et al. Differential immunodiagnosis between cystic hydatid disease and other cross-reactive pathologies. Am J Trop Med Hyg
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- Shakibi JG, Safavian MH, Azar H, Siassi B. Surgical treatment of echinococcal cyst of the heart. Report of two cases and review of the world literature. J Thorac Cardiovasc Surg
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ABSTRACT
INTRODUCTION
