Echocardiographic/ Doppler criteria of normality, the findings in cardiac disease and the genetics of familial dilated cardiomyopathy in Newfoundland dogs

Dilated cardiomyopathy (DCM) is common in pedigree dog breeds including Newfoundlands. The breed predisposition and the familial prevalence within breeds support a genetic basis to the disease. Familial occurrence of DCM has only recently been recognised in man, and echocardiography abnormalities are common in relatives of DCM patients.Echocardiography is the method of choice for confirming the diagnosis of DCM. Echocardiographic/Doppler data are presented from 223 scans from 165 individual Newfoundland dogs. The scans were categorised into six groups based on the clinical presentation, M-mode echocardiography results and the Doppler derived aortic velocity. The Normal group showed no abnormalities (n=86). The DCM (overt or occult) group had a rounded left ventricle and fractional shortening (FS) <22% (n=35). There were two depressed fractional shortening groups, without other abnormalities; one with FS less than 18% (dFS<18%) (n=29) and the other with FS 18-20% (dFS18-20%) (n=24). The left ventricular enlargement (LVE) group was defined as a LV diastolic dimension greater than 55mm (males) or >50 mm (females), without any M-mode evidence of systolic dysfunction (n=8). Dogs with an aortic velocity exceeding 1.7 m/s were defined as showing evidence of subaortic stenosis (SAS group) (n=40).Data from complete echocardiographic/Doppler analysis of the Normal group were assessed for dependence on the gender, age and size of dog (weight or body surface area (BSA)) and the heart rate (mean R-R interval) by linear regression analyses. LV volumes and M-mode measurements were positively correlated with size. Gender was not an important predictor of most echo measurements once data was normalised for BSA. Advancing age was a significant negative predictor of LV volumes and dimensions although influence on wall thickness was not significant. Age also showed a significant influence on diastolic function, assessed by mitral inflow and pulmonary venous flow, similar to changes described in man.The Newfoundland groups were compared. The DCM group had significantly increased LV volume and dimensions and decreased systolic function than other groups. There were few significant differences between the groups for diastolic function parameters. There was considerable overlap between groups for all dimensions and the parameters of systolic function, although the pre-ejection period: ejection time (PEP:ET) ratio appeared to be most sensitive for distinguishing normal from DCM dogs. In both dFS groups and the LVE group, this ratio was intermediate between the Normal and DCM groups, in contrast to other parameters of systolic function. Left atrial dysfunction was also identified in the DCM group, but was less marked in both dFS and the LVE groups. Some dogs in the LVE and dFS groups progressed to develop DCM but a longer duration of study would be required before firm conclusions can be drawn about progression.Most of the dogs in this study were related. Pedigree and segregation analyses were supportive but not conclusive for an autosomal dominant mode of inheritance for DCM. A simulated linkage analysis indicated that this family was sufficiently informative for a genetic linkage analysis study. A pilot study assessing a number of anonymous canine microsatellites confirmed that there was sufficient heterozygosity and polymorphism, despite significant inbreeding, to permit a genetic linkage analysis study. No significant LOD score was achieved for the twelve microsatellites assessed. However, the available data indicate that a genome-wide linkage analysis is likely to be successful, with phenotyping based on the echocardiography data

Canine candidate genes for dilated cardiomyopathy: annotation of and polymorphic markers for 14 genes

BackgroundDilated cardiomyopathy is a myocardial disease occurring in humans and domestic animals and is characterized by dilatation of the left ventricle, reduced systolic function and increased sphericity of the left ventricle. Dilated cardiomyopathy has been observed in several, mostly large and giant, dog breeds, such as the Dobermann and the Great Dane. A number of genes have been identified, which are associated with dilated cardiomyopathy in the human, mouse and hamster. These genes mainly encode structural proteins of the cardiac myocyte.ResultsWe present the annotation of, and marker development for, 14 of these genes of the dog genome, i.e. alpha-cardiac actin, caveolin 1, cysteine-rich protein 3, desmin, lamin A/C, LIM-domain binding factor 3, myosin heavy polypeptide 7, phospholamban, sarcoglycan delta, titin cap, alpha-tropomyosin, troponin I, troponin T and vinculin. A total of 33 Single Nucleotide Polymorphisms were identified for these canine genes and 11 polymorphic microsatellite repeats were developed.ConclusionThe presented polymorphisms provide a tool to investigate the role of the corresponding genes in canine Dilated Cardiomyopathy by linkage analysis or association studies

Evaluation of serum cardiac troponin-I concentrations for diagnosis of infective endocarditis in dogs

Abstract Background Infective endocarditis (IE) in dogs is associated with severe disease and a high case fatality rate but often presents with nonspecific clinical signs. Hypothesis/Objectives Serum concentration of cardiac troponin‐I (cTnI) is elevated in dogs with IE and can differentiate dogs with IE from dogs with other diseases with similar clinical features. Concentration of serum cTnI is negatively correlated with survival time in dogs with IE. Animals Seventy‐two client‐owned dogs; 29 with IE, 27 with stage‐B myxomatous mitral valve disease (MMVD), and 16 with immune‐mediated disease (IMD). Methods Retrospective clinical cohort study. Concentration of serum cTnI was measured in all dogs at time of diagnosis. Clinical findings and echocardiographic interpretation were also recorded. Statistical analyses included Kruskal‐Wallis test, pairwise Mann‐Whitney U tests, receiver operator characteristic, and Cox proportional hazards. Results Serum concentration of cTnI was significantly higher in the IE group (0.69 ng/mL [0.03‐80.8]) than in the MMVD (0.05 ng/mL [0.02‐0.11], P 0.625 ng/mL are supportive of IE

Concurrent right atrial myxoma with visceral haemangiosarcoma in a dog

A 10-year-old crossbreed (labradoodle) was presented with an acute history of vomiting and diarrhoea, with supraventricular tachycardia and ventricular premature complexes. Physical examination revealed mild tachycardia, but no significant abnormalities otherwise. Investigations with echocardiogram and computed tomography identified a right atrial mass, nodular interstitial lung pattern, multiple nodules throughout the hepatic parenchyma and peritoneal effusion. Abdominocentesis confirmed a haemoabdomen. Treatment was declined and the dog was euthanased the same day. Histopathology of the cardiac mass confirmed a cardiac myxoma, which stained Alcian blue-positive, demonstrating the mucin content of the tumour. The hepatic lesions were factor VIII-positive, consistent with a visceral haemangiosarcoma

Clinical features and outcome of dogs and cats with bidirectional and continuous right-to-left shunting patent ductus arteriosus

Background Studies describing the clinical progression of animals with reverse patent ductus arteriosus (PDA) are lacking. Objectives To describe the signalment, presenting signs, echocardiographic features, and survival in a group of dogs and cats with bidirectional and continuous right-to-left PDA. Animals Forty-six client-owned animals included, comprising 43 dogs and 3 cats with bidirectional or continuous right-to-left PDA. Methods Retrospective multicenter study. Medical records and echocardiographic findings reviewed from animals diagnosed with bidirectional or continuous right-to-left PDA. Impact of ductal morphology, spectral Doppler flow profile, PCV, sildenafil treatment at presentation, sildenafil dose, severity of pulmonary hypertension, general anesthesia with or without surgery and the presence of right-sided congestive heart failure (R-CHF) on crude mortality rate were evaluated via Mantel-Cox log rank comparison of Kaplan-Meier survival curves. Univariable and multivariable Cox proportional hazards analysis was performed, and hazard ratio (HR) (95% confidence intervals [CI]) was presented. Results Hindlimb collapse was the most common presenting sign in dogs (n = 16). Clinical signs in cats were variable. Median survival time was 626 days in dogs (range 1-3628 days). Dogs with R-CHF had a shorter median survival time (58 days vs 1839 days, P = .03). Dogs treated with sildenafil at initial presentation survived longer (1839 days vs 302 days, P = .03), which was the only independent predictor of survival (HR 0.35, CI 0.15-0.86, P = 0.021). Conclusions and Clinical Importance Dogs and cats with reverse PDA have a variable clinical presentation and prognosis. Survival time was longer in animals prescribed sildenafil at diagnosis. Dogs with R-CHF at presentation have a worse overall outcome