ABSTRACT
Dilated cardiomyopathy is a primary disease of the heart muscle that has been reported in Holstein-Friesian cattle worldwide in the past 20 years. Nine cases of the condition were compared in terms of their clinical and pathological characteristics with nine unaffected animals matched for age, sex and breed. Their clinical signs included right-sided heart failure with severe subcutaneous oedema, ascites and/or hydrothorax and distended jugular veins. There were no characteristic biochemical or haematological changes. Postmortem, the affected hearts were enlarged with all the chambers dilated and walls of variable thickness. In most cases the kidneys were pale with a pitted surface. Histologically there was marked perimysial and endomysial fibrosis, extensive loss of cardiomyocytes by coagulative or colliquative necrosis, increased variation in the cross-sectional area of the myocardial fibres, and multifocal disarray and vacuolation of myocytes. Scanning electron microscopy showed that in all cases there was a mild myocardial inflammatory infiltrate, either diffuse or multifocal, which was identified by immunohistochemical labelling as T cells.
Subject(s)
Cardiomyopathy, Dilated/veterinary , Cattle Diseases/pathology , Myocardium/pathology , Age Factors , Animals , Cardiomyopathy, Dilated/diagnosis , Cardiomyopathy, Dilated/pathology , Cattle , Cattle Diseases/diagnosis , Female , Fibrosis/pathology , Fibrosis/veterinary , Heart , Immunohistochemistry/veterinary , Male , Microscopy, Electron, Scanning/veterinary , Myocardium/ultrastructure , Myocytes, Cardiac/ultrastructure , Pedigree , Sex FactorsABSTRACT
Bovine dilated cardiomyopathy (BDCM) is a primary disease of the myocardium that has been described in Holstein-Friesian cattle worldwide in the last 20 years. The principal morphological changes in the myocardium are interstitial fibrosis and increased variability in cardiomyocyte size. Sections of heart muscle from nine cases of BDCM and nine unaffected controls matched for age, sex and breed were studied by means of a computer-assisted image analyser to measure the degree of fibrosis, and the cardiomyocyte cellular and nuclear cross-sectional area and length. The amount of connective tissue in the hearts of BDCM cases was increased by 6.7 times, the nuclear transverse cross-sectional area by 1.9 times, and the cardiomyocyte length and cross-sectional area by 1.7 and 1.6 times, respectively. This resulted in an estimated 2.5-fold increase in mean cardiomyocyte volume. Animals with clinical signs of BDCM showed a mean loss of 51% of the total number of cardiomyocytes as compared with controls. Of the five parameters studied, the percentage of fibrosis was found to be the most consistent discriminator for BDCM. It is possible that the degree of fibrosis could be used to distinguish BDCM from other cardiac diseases of cattle.
Subject(s)
Cardiomyopathy, Dilated/pathology , Cardiomyopathy, Dilated/veterinary , Cattle Diseases/pathology , Fibrosis/pathology , Myocytes, Cardiac/pathology , Animals , Cattle , Diagnosis, Differential , Female , Image Processing, Computer-Assisted , MaleABSTRACT
Six of eight pet cats in a closed colony developed overt signs of dysautonomia over a period of seven days; two of them died and one was euthanased. Dysautonomia was confirmed histopathologically in two of these cats, and in the others the diagnosis was based on the characteristic clinical and radiographic findings. In the two apparently unaffected cats abnormal oesophageal motility was demonstrated by fluoroscopy, suggesting that there may be a subclinical form of the disease. The surviving cats had higher and more variable heart rates (mean 165 bpm) than the non-survivors (mean 121 bpm).