DILATED CARDIOMYOPATHY IN SLENDER-TAILED MEERKATS (SURICATA SURICATTA) UNDER HUMAN CARE.

Meerkats (Suricata suricatta) housed at two accredited zoological institutions in the United States were evaluated via echocardiography, thoracic radiography, and blood biomarkers-taurine and feline N-terminal pro-B-type natriuretic peptide-to determine the prevalence and severity of dilated cardiomyopathy (DCM) in both populations. In total, 24 meerkats were evaluated and 7 were diagnosed with DCM based on the following parameters: left ventricular internal diameter at end diastole > 1.30 cm, left ventricular internal diameter at end systole > 1.10 cm, and a fractional shortening of <18%. Echocardiographic parameters were identified and reported for normal and affected meerkats, whereas thoracic radiographs were not useful for screening for DCM. Meerkats with DCM were treated with pimobendan and/or benazepril and furosemide if indicated. Seven meerkats died during the study period, with the majority exhibiting myocardial fibrosis. Of the blood parameters tested, elevated taurine levels were associated with DCM. Further research is necessary to characterize the etiology of DCM in meerkats.

Gene-expression profiling of endomyocardial biopsies from dogs with dilated cardiomyopathy phenotype.

INTRODUCTION: The employment of advanced molecular biology technologies has expanded the diagnostic investigation of cardiomyopathies in dogs; these technologies have predominantly been performed on postmortem samples, although the recent use of endomyocardial biopsy in living dogs has enabled a better premortem diagnostic approach to study the myocardial injury. ANIMALS, MATERIALS, AND METHODS: Endomyocardial biopsies were collected in nine dogs with a dilated cardiomyopathy phenotype (DCM-p) and congestive heart failure and submitted to histologic examination, next-generation sequencing (NGS), and polymerase chain reaction analysis. Data from three healthy dogs (Fastq files) were retrieved from a previously approved study and used as a control group for ribonucleic acid sequencing. RESULTS: Histologic examination revealed endocardial fibrosis in six of nine dogs, whereas lymphocytic interstitial infiltrates were detected in two of nine dogs, and lymphoplasmacytic and macrophage infiltrates were detected in one of nine dogs. On polymerase chain reaction analysis, two dogs tested positive for canine parvovirus two and one dog for canine distemper virus. Gene-expression pathways involved in cellular energy metabolism (especially carbohydrates-insulin) and cardiac structural proteins were different in all DCM-p dogs compared to those in the control group. When dogs with lymphocytic interstitial infiltrates were compared to those in the control group, NGS analysis revealed the predominant role of genes related to inflammation and pathogen infection. CONCLUSIONS: Next-generation sequencing technology performed on in vivo endomyocardial biopsies has identified different molecular and genetic factors that could play a role in the development and/or progression of DCM-p in dogs.

Dilated cardiomyopathy phenotype in Callithrix penicillata (E. Geoffroy, 1812): Case report.

Dilated cardiomyopathy (DCM) is a disease of the heart muscle diagnosed by alterations resulting from ventricular systolic dysfunction with enlargement of the heart chambers, which is still underdiagnosed in non-human primates. This report is the first case of the DCM phenotype diagnosed by echocardiography and confirmed by necropsy in Callithrix penicillata.

Dilated cardiomyopathy of possible dietary origin in a cat.

An 11-year-old spayed female domestic shorthaired cat was diagnosed with severe dilated cardiomyopathy (DCM) and congestive heart failure. The cat had been eating cat foods that were high in pulses (e.g. peas, lentils, chickpeas). Neither plasma nor whole blood taurine concentrations were deficient. Primary treatment included furosemide, pimobendan, and clopidogrel, and changing to diets that did not contain pulses (a taurine supplements was not administered). The cat's clinical signs improved, high-sensitivity cardiac troponin I concentrations decreased, and echocardiographic measurements stayed relatively stable for over one year after initiating cardiac medications and changing the diet. Ultimately, the cat was euthanized for worsening congestive heart failure 374 days after the diagnosis of DCM. Infectious disease testing during the time of clinical surveillance was negative. Routine histopathology of the heart was unremarkable, but electron microscopy of the left ventricle showed large numbers of mitochondria of variable size and structure. A moderate number of lamellar bodies and autophagic vacuoles also were noted. This case report illustrates an unusual case of a cat with DCM unrelated to taurine deficiency. The relative roles of diet change, cardiac medications, and a dedicated owner are unclear, but this cat's relatively long survival time is similar to that seen after diet change in dogs and cats with DCM eating high-pulse diets.

Naturally occurring canine laminopathy leading to a dilated and fibrosing cardiomyopathy in the Nova Scotia Duck Tolling Retriever.

Dilated cardiomyopathy (DCM) is characterized by decreased systolic function and dilation of one or both ventricles, often leading to heart failure or sudden death. Two 10-month-old sibling Nova Scotia Duck Tolling Retrievers (NSDTR) died acutely with evidence of dilated cardiomyopathy with myocardial fibrosis. Association analysis using two cases and 35 controls identified three candidate regions homozygous in the two cases. Whole genome sequencing identified a frameshift deletion in the LMNA gene (NC_049228.1:g.41688530del, NP_001274080:p.(Asp576ThrfsTer124)). Three retrospectively identified NSDTRs with sudden death before 2 years of age and severe myocardial fibrosis were also homozygous for the deletion. One 5 year old with sudden death and myocardial fibrosis was heterozygous for the deletion. This variant was not identified in 722 dogs of other breeds, nor was it identified to be homozygous in 784 NSDTR. LMNA codes for lamin A/C proteins, which are type V intermediate filaments that provide structural support to the nuclear membrane. In humans, LMNA variants can cause DCM with sudden death as well as diseases of striated muscles, lipodystrophy, neuropathies, and accelerated aging disorders. This frameshift deletion is predicted to affect processing of prelamin A into lamin A. Pedigree analysis in the NSDTR and functional evaluation of heterozygotes is consistent with a predominantly recessive mode of inheritance and possibly low penetrance in heterozygotes in contrast to people, where most pathogenic LMNA variants are dominantly inherited.

Identification of novel genetic risk factors of dilated cardiomyopathy: from canine to human.

BACKGROUND: Dilated cardiomyopathy (DCM) is a life-threatening heart disease and a common cause of heart failure due to systolic dysfunction and subsequent left or biventricular dilatation. A significant number of cases have a genetic etiology; however, as a complex disease, the exact genetic risk factors are largely unknown, and many patients remain without a molecular diagnosis. METHODS: We performed GWAS followed by whole-genome, transcriptome, and immunohistochemical analyses in a spontaneously occurring canine model of DCM. Canine gene discovery was followed up in three human DCM cohorts. RESULTS: Our results revealed two independent additive loci associated with the typical DCM phenotype comprising left ventricular systolic dysfunction and dilatation. We highlight two novel candidate genes, RNF207 and PRKAA2, known for their involvement in cardiac action potentials, energy homeostasis, and morphology. We further illustrate the distinct genetic etiologies underlying the typical DCM phenotype and ventricular premature contractions. Finally, we followed up on the canine discoveries in human DCM patients and discovered candidate variants in our two novel genes. CONCLUSIONS: Collectively, our study yields insight into the molecular pathophysiology of DCM and provides a large animal model for preclinical studies.

Possible development and resolution of dilated cardiomyopathy phenotype secondary to atypical hypoadrenocorticism in a dog.

OBJECTIVE: To report the possible occurrence of dilated cardiomyopathy phenotype associated with atypical hypoadrenocorticism and subsequent marked improvement with treatment in a mixed breed dog. CASE SUMMARY: A 4.5-year-old, neutered male mixed breed dog was evaluated for a history and clinicopathological changes consistent with atypical hypoadrenocorticism. The dog was being fed a grain-free diet. While hospitalized for supportive care and diagnostics, the patient developed and was diagnosed with biventricular congestive heart failure secondary to dilated cardiomyopathy phenotype and IV fluid administration. The left-sided congestive heart failure resolved with discontinuation of IV fluid therapy and short-term administration of diuretics. After treatment of atypical hypoadrenocorticism with glucocorticoid supplementation, and while continuing to be fed varying grain-free diets, the patient's dilated cardiomyopathy phenotype largely resolved. The patient fully recovered and did not require any long-term cardiac medications. NEW OR UNIQUE INFORMATION PROVIDED: Development of dilated cardiomyopathy phenotype has not been described in dogs as a sequela of untreated hypoadrenocorticism but has been reported in human literature. Given the fact that standard management of hypoadrenocorticism typically involves aggressive fluid resuscitation, awareness of this potential sequela is important for patients that fail to respond or develop signs consistent with volume overload.

MANAGEMENT OF SUSPECTED DILATED CARDIOMYOPATHY WITH PIMOBENDAN IN TWO LEOPARD SHARKS (TRIAKIS SEMIFASCIATA).

Two adult male leopard sharks (Triakis semifasciata) under managed care were diagnosed with suspected dilated cardiomyopathy. Clinical signs included lethargy, inappetence, and regurgitation. On cardiac ultrasound, fractional shortening was 14% and 10%, respectively (versus 21%-31% in four healthy conspecifics). Ventricular end-diastolic diameter to body weight ratio was 1.72 cm/kg in Case 1 (versus 0.52-1.24 cm/kg in four conspecifics). These results collectively suggested a dilated cardiomyopathy. Treatment was implemented with oral pimobendan at 0.3 mg/kg q48h for 1 mon. The pimobendan dose was increased to 0.5 mg/kg 3/wk, following plasmatic dosage of pimobendan and its metabolite. After 3 mon, fractional shortening increased to 38% and 20%, respectively, sharks regained a normal appetite, and body weight increased by 50% in one individual. After 2 yr, both individuals remained clinically normal, and no adverse effect was noted with pimobendan administration. Pimobendan plasma concentration suggested that this medication was well absorbed in this species.

An ABCC9 Missense Variant Is Associated with Sudden Cardiac Death and Dilated Cardiomyopathy in Juvenile Dogs.

Sudden cardiac death in the young (SCDY) is a devastating event that often has an underlying genetic basis. Manchester Terrier dogs offer a naturally occurring model of SCDY, with sudden death of puppies as the manifestation of an inherited dilated cardiomyopathy (DCM). We performed a genome-wide association study for SCDY/DCM in Manchester Terrier dogs and identified a susceptibility locus harboring the cardiac ATP-sensitive potassium channel gene ABCC9. Sanger sequencing revealed an ABCC9 p.R1186Q variant present in a homozygous state in all SCDY/DCM-affected dogs (n = 26). None of the controls genotyped (n = 398) were homozygous for the variant, but 69 were heterozygous carriers, consistent with autosomal recessive inheritance with complete penetrance (p = 4 × 10-42 for the association of homozygosity for ABCC9 p.R1186Q with SCDY/DCM). This variant exists at low frequency in human populations (rs776973456) with clinical significance previously deemed uncertain. The results of this study further the evidence that ABCC9 is a susceptibility gene for SCDY/DCM and highlight the potential application of dog models to predict the clinical significance of human variants.

Long-term outcome and troponin I concentrations in Great Danes screened for dilated cardiomyopathy: an observational retrospective epidemiological study.

INTRODUCTION: Dilated cardiomyopathy (DCM) is common in Great Danes (GDs) but screening for this condition can be challenging. We hypothesised that cardiac troponin-I (cTnI) concentration is elevated in GDs with DCM and/or ventricular arrhythmias (VAs), and is associated with reduced survival time in GDs. ANIMALS: One hundred and twenty-four client-owned GDs assigned echocardiographically as normal (n = 53), equivocal (n = 37), preclinical DCM (n = 21), or clinical DCM (n = 13). MATERIALS AND METHODS: A retrospective epidemiological study. Echocardiographic diagnosis, VAs, and contemporaneous cTnI concentrations were recorded. Diagnostic accuracy and cTnI cut-offs were determined with receiver operating characteristic analyses. Effects of the cTnI concentration and disease status on survival and cause of death were explored. RESULTS: Median cTnI was greater in clinical DCM (0.6 ng/mL [25th-75th percentiles: 0.41-1.71 ng/mL]) and GDs with VAs (0.5 ng/mL [0.27-0.80 ng/mL], P<0.001). Elevated cTnI detected these dogs with good accuracy (area under the curve: 0.78-0.85; cut-offs 0.199-0.34 ng/mL). Thirty-eight GDs (30.6%) suffered a cardiac death (CD); GDs suffering CD (0.25 ng/mL [0.21-0.53 ng/mL]) and specifically sudden cardiac death (SCD) (0.51 ng/mL [0.23-0.72 ng/mL]) had higher cTnI than GDs dying of other causes (0.20 ng/mL [0.14-0.35 ng/mL]; P<0.001). Elevated cTnI (>0.199 ng/mL) was associated with shorter long-term survival (1.25 years) and increased risk of SCD. Great Danes with VAs had shorter survival times (0.97 years). CONCLUSIONS: A cardiac troponin-I concentration is a useful adjunctive screening tool. Elevated cTnI is a negative prognostic indicator.

Pit bull-type breeds with dilated cardiomyopathy eating nontraditional diets improve after diet change (2015-2022).

OBJECTIVE: To compare signalment, clinical signs, diet, echocardiographic findings, and outcome for pit bull-type breeds diagnosed between 2015 and 2022 with dilated cardiomyopathy (DCM) or with DCM diagnosed by a cardiologist but that did not meet all study echocardiographic criteria (DCM-C). ANIMALS: 91 dogs with DCM and 11 dogs with DCM-C. PROCEDURES: Data were collected on clinical findings, echocardiographic measurements, and diet at the time of diagnosis (for 76/91 dogs); echocardiographic changes; and survival. RESULTS: For dogs with diet information available for time of diagnosis, 64/76 (84%) dogs were eating nontraditional commercial diets, while 12/76 (16%) were eating traditional commercial diets. There were few differences between diet groups at baseline, with congestive heart failure and arrhythmias common in both groups. Thirty-four dogs with known baseline diet and diet change status had follow-up echocardiograms between 60 and 1,076 days later (traditional diet, n = 7; nontraditional diet that changed diets, 27; and nontraditional diet group without diet change, 0). Dogs in the nontraditional diet group that changed diets had a significantly greater decrease in normalized left ventricular diameter (diastolic, P = .02; systolic, P = .048) and the left atrium-to-aorta ratio (P = .002) and a significantly greater increase in fractional shortening (P = .02) compared to dogs eating traditional diets. Dogs eating nontraditional diets with diet change (n = 45; P < .001) and dogs eating traditional diets (12; P < .001) had a significantly longer survival time compared to dogs eating nontraditional diets without diet change (4). Dogs with DCM-C also had significant echocardiographic improvements after diet change. CLINICAL RELEVANCE: Congestive heart failure and arrhythmias were common in pit bull-type breeds with DCM. Those eating nontraditional diets that changed diets had significant improvements in echocardiographic measurements after diet change.

The Pulse of It: Dietary Inclusion of Up to 45% Whole Pulse Ingredients with Chicken Meal and Pea Starch in a Complete and Balanced Diet Does Not Affect Cardiac Function, Fasted Sulfur Amino Acid Status, or Other Gross Measures of Health in Adult Dogs.

BACKGROUND: Pulses are an attractive alternative protein source for all mammals; however, recent reports suggest that these ingredients may be related to developing dilated cardiomyopathy in dogs. OBJECTIVES: The primary objective of this study was to quantify the effects of dietary pulse intake by adult dogs on cardiac function using echocardiographic measurements and cardiac biomarkers N-terminal pro-B-type natriuretic peptide and cardiac troponin I (cTnI). Second, to investigate the effects of pulse consumption on plasma sulfur amino acid (SAA) concentrations as pulses are generally low in SAA and may limit taurine synthesis. Last, to assess the general safety and efficacy of feeding pulse-containing diets on canine body composition and hematological and biochemical indices. METHODS: Twenty-eight privately-owned domestic Siberian Huskies (13 females; 4 intact, and 15 males; 6 intact) with a mean age of 5.3 ± 2.8 y (± SD) were randomly assigned to 1 of 4 dietary treatments (n = 7/treatment), with equal micronutrient supplementation and increasing whole pulse ingredient inclusion (0%, 15%, 30%, and 45%) with pea starch used to balance protein and energy. RESULTS: After 20 wks of feeding, there were no differences (P > 0.05) in echocardiographic parameters, N-terminal pro-B-type natriuretic peptide, and cTnI concentrations among treatments or across time within treatment (P > 0.05), indicating no differences in cardiac function among treatments. Concentrations of cTnI remained below the safe upper limit of 0.2 ng/mL for all dogs. Plasma SAA status, body composition, and hematological and biochemical indices were similar among treatments and over time (P > 0.05). CONCLUSIONS: The results from this study suggest that increasing the inclusion of pulses up to 45% with the removal of grains and equal micronutrient supplementation does not impact cardiac function concurrent with dilated cardiomyopathy, body composition, or SAA status and is safe for healthy adult dogs to consume when fed for 20 wks.

Comparison of echocardiography, biomarkers and taurine concentrations in cats eating high- or low-pulse diets.

OBJECTIVES: There are ongoing investigations into diet-associated dilated cardiomyopathy in dogs, but there has been minimal investigation into possible diet-associated dilated cardiomyopathy in cats. The objective of this study was to compare cardiac size and function, cardiac biomarkers and taurine concentrations in healthy cats eating high- vs low-pulse diets. We hypothesized that cats eating high-pulse diets would have larger hearts, lower systolic function and higher biomarker concentrations than cats eating low-pulse diets and that there would be no difference in taurine concentrations between the diet groups. METHODS: Echocardiographic measurements, cardiac biomarkers, and plasma and whole-blood taurine concentrations were compared between cats eating high- and low-pulse commercial dry diets in a cross-sectional study. RESULTS: There were no differences between the high- (n = 21) and low-pulse (n = 31) diet groups with regard to age, sex and breed, but more cats in the high-pulse group were overweight or obese (67% vs 39%; P = 0.05). Diet duration was not different in the groups, but the range was wide (6-120 months). No differences were found between the diet groups for key cardiac measurements, biomarker concentrations, or plasma or whole-blood taurine concentrations. However, there were significant negative correlations between diet duration and measures of left ventricular wall thickness in the high-pulse, but not the low-pulse, diet group. CONCLUSIONS AND RELEVANCE: This study did not detect significant associations between high-pulse diets and cardiac size, function and biomarkers, but the secondary observation of significant negative correlations between time on high-pulse diets and left ventricular wall thickness warrants further evaluation.

Impact of blood tube additives and timing of sampling on blood taurine concentrations in clinically healthy dogs.

INTRODUCTION: Dilated cardiomyopathy can be associated with taurine deficiency in dogs. Blood taurine concentrations can be analyzed in whole blood (WB) and plasma. The study objectives were to investigate agreement between taurine concentrations measured in WB, heparin plasma, and EDTA plasma, determine intraindividual variation in healthy dogs, and evaluate if time from feeding to sampling impacts concentrations. ANIMALS: Ten English Cocker spaniels and 10 dogs of various breeds. MATERIALS AND METHODS: Dogs were fasted 12 h prior to initial blood sampling, and the blood was collected at five occasions over eight h. Food was offered immediately after first and one h after fourth sampling time point. RESULTS: Agreement between taurine concentrations in EDTA plasma and heparinized plasma was good (mean difference 4.5 nmol/mL, 95% confidence interval (CI) 36.8-45.8 nmol/mL). Whole blood concentrations were systematically higher than EDTA and heparin plasma concentrations (mean difference 132.7 nmol/mL, 95% CI 23.6-241.8 nmol/mL, and 127.6 nmol/mL, 95% CI 28.6-226.6 nmol/mL, respectively, all P < 0.001). Intraindividual daily variations in taurine concentration were seen in all additives, with largest variations in plasma (P < 0.001). Taurine concentration in heparinized plasma was higher at first and fifth sampling time points compared to the fourth (P = 0.014). DISCUSSION: Agreement was found between taurine concentrations measured in different additives, with expected higher concentration in WB than plasma. Taurine concentrations measured in heparinized plasma varied with sampling time point. Intraindividual daily variations were observed in all additives, but mainly in plasma samples. CONCLUSION: Taurine concentrations in dogs with suspected deficiency should be interpreted with caution.

Comparison of echocardiographic measurements and cardiac biomarkers in healthy dogs eating nontraditional or traditional diets.

BACKGROUND: There has been a recent association between nontraditional diets and development of diet-associated dilated cardiomyopathy (DCM) in dogs. HYPOTHESIS/OBJECTIVES: To compare echocardiographic measurements and cardiac biomarkers between healthy dogs eating nontraditional vs traditional diets. We hypothesized that dogs eating nontraditional diets would have lower measures of systolic myocardial performance compared to dogs eating traditional diets. ANIMALS: Forty-six healthy dogs: 23 eating nontraditional diets and 23 eating traditional diets. METHODS: Prospective, cross-sectional study. Dogs were divided into groups based on diet ingredients. Dogs underwent 2-dimensional (2D), 3-dimensional (3D), and Doppler echocardiographic examinations and analysis of plasma N-terminal prohormone of B-type natriuretic peptide, serum cardiac troponin I, and whole blood and plasma taurine concentrations. RESULTS: Mean 2D ejection fraction (EF) was lower for dogs eating nontraditional diets (48.65 ± 7.42%) vs dogs eating traditional diets (56.65 ± 4.63%; P < .001; mean difference 8.0% [4.0%-12.0%] 95% confidence interval [CI]). Mean 3D EF was lower for dogs eating nontraditional diets (45.38 ± 7.35%) vs dogs eating traditional diets (57.58 ± 4.84%; P < .001; 12.0% [8.0%-16.0%] 95% CI). Mean 2D left ventricular end-systolic volumes, indexed to body weight, were significantly higher in dogs eating nontraditional diets (1.46 ± 0.08 mL/kg) vs dogs eating traditional diets (1.06 ± 0.08 mL/kg; P = .002; 0.4 mL/kg [0.18-0.62 mL/kg] 95% CI). CONCLUSIONS AND CLINICAL IMPORTANCE: Healthy dogs eating nontraditional diets had lower indices of systolic function and larger left ventricular volumes compared to dogs eating traditional diets. Screening of apparently healthy dogs eating nontraditional diets might allow for early detection of diet-associated DCM.

Total bilirubin is an independent predictor of death in dogs with degenerative valvular disease and dilated cardiomyopathy.

INTRODUCTION: There is little published regarding the association between canine cardiovascular disease and the hepatic system. The objective of the study was to evaluate the relationship between hepatic parameters, survival, and disease stages of dogs with either dilated cardiomyopathy (DCM) or degenerative valvular disease (DVD). ANIMALS, MATERIALS, AND METHODS: Retrospective study analyzing hepatic parameters in dogs with DVD or DCM in American College of Veterinary Internal Medicine stage B or C and healthy control dogs. Associations between liver parameters, type and stage of disease, and survival were investigated. RESULTS: Ninety-nine dogs were included in the study: 61 DVD, 22 DCM, and 16 controls. Differences in liver parameter concentrations between DCM, DVD, and disease stages were found. Univariate analysis identified alanine aminotransferase (P < 0.001), aspartate aminotransferase (P = 0.02), and total bilirubin (P = 0.005) as predictors of mortality. In the multivariate analysis, total bilirubin remained an independent predictor of mortality. CONCLUSIONS: The observed differences between DCM, DVD, and disease stages are likely consistent with disease-specific hemodynamics and progression of disease. This and the role of total bilirubin as an independent predictor for mortality indicate that in dogs with DVD and DCM the cardiovascular-hepatic interaction might be of relevance for disease progression and outcome, as reported for humans with cardiac disease. Further studies into the role of hepatic function in canine cardiac disease are required.

DIAGNOSIS AND MANAGEMENT OF SUSPECTED CONGESTIVE HEART FAILURE SECONDARY TO DILATED CARDIOMYOPATHY IN A SAND TIGER SHARK (CARCHARIAS TAURUS) WITH ESTABLISHMENT OF PRELIMINARY NORMAL ECHOCARDIOGRAPHIC INDICES.

Elasmobranch cardiac anatomy and physiology has been well described; however, there is a dearth of information regarding cardiac disease. In support of a clinical case of suspected congestive heart failure in a 22-yr-old male sand tiger shark (Carcharias taurus), a study was undertaken to identify feasible echocardiographic imaging planes and preliminary indices for this species. Eleven echocardiograms were performed on six apparently healthy sand tiger sharks. Echocardiographic parameters are presented using descriptive statistics, including mean, median, standard deviation (SD), minimum and maximum values. These data were utilized for the diagnosis and clinical management of the affected shark. The shark initially presented with increased respiratory effort, dependent, peripheral edema, and anemia. Echocardiography revealed atrial, ventricular, and sinus venosus dilation. As congestive heart failure secondary to dilated cardiomyopathy was strongly suspected, therapy was initiated with oral benazepril and torsemide, and later pimobendan. After a year of therapy, clinical signs resolved. Cardiac size and function improved on echocardiography with a reduction in sinus venosus dilation, maximum and minimum atrial and ventricular inner diameters, and an increase in atrial and ventricular fractional shortening. Cardiac disease in elasmobranchs may be underdiagnosed, so it may be necessary to develop standardized ultrasound techniques and cardiac measurements for each species of elasmobranch managed within zoos and aquaria.

Ventricular systolic dysfunction in dogs diagnosed with hypoadrenocorticism.

In human patients with hypoadrenocorticism, a secondary dilated cardiomyopathy is noted that has been reported to resolve with replacement steroid therapy. A similar secondary dilated cardiomyopathy in dogs with hypoadrenocorticism has not been previously described. We present three dogs concurrently diagnosed with hypoadrenocorticism and ventricular dilation with systolic dysfunction. Two dogs were presented with clinical signs consistent with biventricular congestive heart failure and a third dog was presented with signs of acute hypoadrenocorticism without congestive heart failure. All dogs recovered to normal cardiac size and function with therapy. Hypoadrenocorticism should be considered as a differential diagnosis in dogs that present with ventricular dilation and systolic dysfunction if there are other indicators in the clinical and laboratory testing. Additionally, a thorough cardiac evaluation should be recommended for dogs that are found to have a heart murmur at the time of diagnosis of hypoadrenocorticism.

Responses in randomised groups of healthy, adult Labrador retrievers fed grain-free diets with high legume inclusion for 30 days display commonalities with dogs with suspected dilated cardiomyopathy.

Early responses in healthy adult dogs fed grain-free diets with high inclusion of split peas (20%) and lentils (40%) that may lead to canine diet-induced dilated cardiomyopathy (DCM) were investigated. To help understand the clinical relevance of the findings, a survey of electronic health records (EHR) was conducted of dogs with and without suspected DCM for comparison. Control and Test diets were fed to Labrador retriever dogs for 30 days (n = 5 and 6, respectively). Blood and urine samples collected at baseline and days 3, 14 and 28/30 were analyzed for hematology, clinical biochemistry and taurine concentrations. The EHRs of dogs at Banfield® Pet Hospitals in the 2-year period 2018-2019 were surveyed, revealing 420 dogs diagnosed with DCM, which were compared with 420 breed, gender and age-matched healthy control dogs. Compared to baseline values, feeding the Test diet for 28 days caused progressive, significant (p < 0.001) decreases in red blood cell counts (RBC), hematocrit and total hemoglobin by 7.7, 8.3 and 6.3%, respectively, and a 41.8% increase in plasma inorganic phosphate. Commonalities in these parameters were observed in clinical DCM cases. Regarding taurine status, Test dogs transiently increased whole-blood (23.4%) and plasma (47.7%) concentrations on day 14, while taurine:creatinine ratio in fresh urine and taurine in pooled urine were reduced by 77 and 78%, respectively, on day 28/30. Thus grain-free, legume-rich Test diets caused reduced RBC and hyperphosphatemia, findings also indicated in dogs with suspected DCM. Changes in taurine metabolism were indicated. The data will aid in generating hypotheses for future studies.

Prospective study of dilated cardiomyopathy in dogs eating nontraditional or traditional diets and in dogs with subclinical cardiac abnormalities.

BACKGROUND: Recent studies have investigated dogs with presumed diet-associated dilated cardiomyopathy (daDCM), but prospective studies of multiple breeds are needed. HYPOTHESIS/OBJECTIVES: To evaluate baseline features and serial changes in echocardiography and cardiac biomarkers in dogs with DCM eating nontraditional diets (NTDs) or traditional diets (TDs), and in dogs with subclinical cardiac abnormalities (SCA) eating NTD. ANIMALS: Sixty dogs with DCM (NTD, n = 51; TDs, n = 9) and 16 dogs with SCA eating NTDs. METHODS: Echocardiography, electrocardiography, and measurement of taurine, cardiac troponin I, and N-terminal pro-B-type natriuretic peptide were performed in dogs with DCM or SCA. Diets were changed for all dogs, taurine was supplemented in most, and echocardiography and cardiac biomarkers were reassessed (3, 6, and 9 months). RESULTS: At enrollment, there were few differences between dogs with DCM eating NTDs or TDs; none had low plasma or whole blood taurine concentrations. Improvement in fractional shortening over time was significantly associated with previous consumption of a NTD, even after adjustment for other variables (P = .005). Median survival time for dogs with DCM was 611 days (range, 2-940 days) for the NTD group and 161 days (range, 12-669 days) for the TD group (P = .21). Sudden death was the most common cause of death in both diet groups. Dogs with SCA also had significant echocardiographic improvements over time. CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with DCM or SCA previously eating NTDs had small, yet significant improvements in echocardiographic parameters after diet changes.