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.
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).
Bovine dilated cardiomyopathy (BDCM) is a primary disease of the heart muscle that has been reported in Holstein-Friesian cattle worldwide in the last twenty years. Histopathological, immunocytochemical and morphometrical analyses were conducted on heart tissue obtained from two groups of cattle: nine animals diagnosed with BDCM and nine unaffected animals matched for sex, breed and age. Histopathology revealed marked perimysial and endomysial fibrosis, extensive cardiomyocyte loss with two different morphological appearances, increased variation in myofibre cross-sectional area, multifocal myocyte disarray and vacuolation. Morphometrical analysis identified an approximate 7-fold increase in connective tissue and it is suggested that the degree of increased fibrosis in bovine cardiac muscle is a reliable discriminator for BDCM. Post-analysis calculations estimated a near 50% loss of cardiomyocytes with a 2.5-fold increase in size of surviving cardiomyocytes in animals with BDCM. Possible pathogenetic mechanisms leading to the cardiac failure are discussed. Diffuse or multifocal myocardial infiltration by T-lymphocytes was also observed, suggesting a possible viral aetiology. However, quantitative Taq-Man(R) PCR analysis failed to provide evidence of bovine enterovirus infection.
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).
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