Endocardial fibroelastosis in a dog with congestive heart failure.

In a 6-month-old, intact female, Japanese spitz presenting with severe dyspnea, lung ultrasonography revealed confluent B lines associated with severe echocardiographic left sided volume overload and systolic dysfunction. A congenital shunt or valvular dysplasia was not demonstrable. On electrocardiogram, there was a constant sinus rhythm, respectively sinus tachycardia. Cardiac troponin I was normal. Within 2 days of admission, the dog died of heart failure. On macroscopic postmortem examination, the left ventricle and atrium were markedly dilated, and the left ventricular endocardium had a mild diffuse whitish appearance. Histopathology revealed moderate to severe thickening of the left ventricular endocardium, composed mostly of abundant elastic fibers and fewer collagen fibers, diagnostic for endocardial fibroelastosis. In addition, there were mild degenerative changes of the atrioventricular valves. Endocardial fibroelastosis is a rare congenital disease and should be considered in a young dog if more common causes of echocardiographic dilated cardiomyopathy phenotype are ruled out.

Dilated cardiomyopathy with endocardial fibroelastosis in a juvenile Pallas cat.

Dilated cardiomyopathy (DCM) is a myocardial disease characterized by ventricular chamber dilation associated with systolic myocardial dysfunction in the absence of other cardiac lesions. DCM occasionally develops in conjunction with proliferation of fibroelastic fibers in the endocardium, producing endocardial fibroelastosis (EFE). Although early reports describe EFE as a primary disease, evidence now suggests that EFE may develop as a response to myocardial dysfunction. Echocardiographic evaluation of a 4-wk-old Pallas cat ( Otocolobus manul) with respiratory distress revealed enlargement of both atria, enlarged end-systolic left ventricular dimension, and left ventricular dilation. DCM was diagnosed, and the cat was euthanized, given the poor prognosis. Postmortem examination revealed pericardial effusion and biventricular and biatrial enlargement. The interventricular septum and free walls of ventricles were thin. Histologically, the endocardium of the left and right ventricles was diffusely thickened; Verhoeff-Van Gieson staining of the left ventricular endocardium revealed a moderate amount of endocardial accumulation of elastin and collagen. These fibers were more prominent in papillary muscles and around coronary blood vessels. Based on these findings, we diagnosed DCM with EFE. Cardiac diseases are rarely diagnosed in wild felids.

Endocardial fibroelastosis in two related tiger cubs (Panthera tigris).

Two tiger cubs (Panthera tigris) from the same litter were evaluated for suspected cardiac disease. Two cubs with a dilated cardiomyopathy phenotype were diagnosed with endocardial fibroelastosis based on necropsy and histopathologic examinations. Echocardiography revealed salient anatomic and functional aspects of this cardiac disorder. This is the first report of endocardial fibroelastosis in this species.

Endocardial fibroelastosis in a quarterhorse mare.

A 4-year-old crossbred Quarterhorse mare was submitted to the Clemson Veterinary Diagnostic Center for necropsy examination with a chronic history of inappetence, weight loss and lethargy. Prior to death the horse had developed mild diarrhoea and began showing evidence of colic. Necropsy examination revealed a markedly enlarged heart due predominantly to marked dilation of the right atrium, tortuous congested mesenteric blood vessels, marked ascites, pleural effusion and pulmonary oedema. Further examination of the heart showed the endocardium of the left side of the heart, including the mitral valve leaflets, to be diffusely thickened. Microscopically, the endocardial thickening was due to deposition of fibrous connective tissue and elastin fibres. These findings are consistent with a diagnosis of endocardial fibroelastosis.

Congenital endocardial fibroelastosis in a dog.

A 9-week-old Weimaraner was tentatively diagnosed clinically with congenital left-sided heart failure. On necropsy, diffuse fibroplasia over the left ventricular endocardium; small, deformed papillary muscles; and pulmonary congestion were evident. Microscopically, the fibroplasia extended into the myocardium and cardiomyocytes, and Purkinje fibers were degenerated, consistent with congenital endocardial fibroelastosis.

Endocardial fibroelastosis in a dog.

Endocardial fibroelastosis is an uncommon congenital heart disease in dogs that may be manifested by signs of left-sided congestive heart failure. A three-month-old, male, Fila Brasileiro dog developed signs of generalised heart failure. Physical examination revealed normal temperature, ascites, and pale and cyanotic mucous membranes. The pup died just after radiography which revealed ascites, hepatomegaly, severe cardiac enlargement and pulmonary oedema. At necropsy, serosanguineous fluid in the thorax and abdomen, pulmonary oedema, right ventricular dilatation, hypertrophy and dilatation of the left ventricle, and mitral valve incompetence were observed. The histopathological examination demonstrated that the thickening of the endocardium of the left atrium and left ventricle was due to the presence of elastic and collagen fibres, although there were no signs of an inflammatory process.

Retrospective study of congenital heart defects in 151 dogs.

The case records of 151 dogs diagnosed with congenital heart disease were reviewed retrospectively. The most common defect was aortic stenosis, accounting for 35 per cent of all cases, followed by pulmonic stenosis (20 per cent), ventricular septal defect (12 per cent), patent ductus arteriosus (11 per cent), mitral valve dysplasia (8 per cent), tricuspid valve dysplasia (7 per cent), endocardial fibroelastosis (1.9 per cent) and tetralogy of Fallot (0.6 per cent). Fifty-one breeds were represented, with golden retrievers, German shepherd dogs and boxers predominating. No overall sex predilection was obvious. Seventy-five per cent of the dogs were asymptomatic at presentation. The defects most often associated with presenting symptoms, such as dyspnoea, syncope, ascites, failure to grow and depression, were mitral valve dysplasia, atrial septal defect, tricuspid valve dysplasia and endocardial fibroelastosis. The latter presented with the most severe signs of heart failure. In some cases of aortic stenosis and pulmonic stenosis, where the defect could not be accurately visualised with two-dimensional echocardiography, Doppler echocardiographic examination was needed for definitive diagnosis.

Endocardial fibroelastosis in common domestic cats in the UK.

Endocardial fibroelastosis (EFE) is a pathological disorder characterized by a diffuse and elastic thickening of the endocardium. It is often thought to be congenital as most victims are infants who die of congestive heart failure before reaching one year of age. A naturally occurring animal model of EFE was proposed more than a decade ago on the basis of one pair of adult pure-bred Burmese cats which produced offspring consistently affected with EFE. In the present study a case of EFE is described which occurred in a closed colony of experimental SPF cats. A 5-week-old kitten which was found dead showed hydrothorax, hydropericardium and oedematous lungs at necropsy. Histological examination of the heart revealed left atrio-ventricular dilation with severe, diffuse endocardial thickening which did not extend into the myocardium. A retrospective study was carried out on stored tissues of two further kittens and one adult male cat from the colony which had died during a period of 2 years. The hearts of all the animals showed endocardial thickening in the left atria and ventricle but not in the right chambers. Over a period of 12 years of existence of this colony considerable inbreeding had occurred and it is concluded that an inherited factor was responsible for the disorder.

Endocardial fibroelastosis and tricuspid valve insufficiency in a calf.

A 5-month-old Holstein heifer had clinical signs of tricuspid valve insufficiency and histopathologic evidence of endocardial fibroelastosis. The calf had a 3-week history of weight loss, abdominal distention, dyspnea, and decreased appetite. Physical examination revealed signs of right-sided heart failure, and a systolic murmur (II/VI) was heard best over the right heart base. Results of cardiac catheterization and echocardiography indicated tricuspid valve insufficiency and right-sided heart failure. The calf was euthanatized after not responding to treatment with penicillin, furosemide, and removal of fluid from the thorax and abdomen. Necropsy findings included multifocal areas of thickening and opacification of the endocardium of the left and right ventricles. Excessive elastic fibers, consistent with fibroelastosis, were seen by use of special stains applied to sections of endocardium.