Resolution of dynamic left ventricular outflow tract obstruction and reversible left ventricular hypertrophy in 4 cats.

This case series describes spontaneous resolution of systolic anterior motion of the mitral valve, cessation of a dynamic left ventricular outflow tract obstruction, and reverse cardiac remodeling in 4 young cats. Following initial presentation with or without congestive heart failure, subsequent rechecks documented resolution of systolic anterior motion of the mitral valve and normalization of left heart dimensions. Those cats originally presented with congestive heart failure were successfully weaned off diuretic medications. Atenolol was prescribed to all 4 cats, and all remained on oral atenolol through the final recheck. There was no documented recurrence of progressive heart disease and heart failure in any of the cats. Consideration is given to transient myocardial thickening, spontaneous resolution of mitral valve dysplasia, and response to beta-1 adrenergic antagonism as possible underlying mechanisms. Key clinical message: When presented with young cats with hypertrophic obstructive cardiomyopathy, veterinarians should consider multiple differential diagnoses, as lifespan in these cases may be longer than typically expected for cats with primary hypertrophic cardiomyopathy, even with concurrent congestive heart failure.

Résolution d'une obstruction dynamique de la voie d'éjection du ventricule gauche et d'une hypertrophie réversible du ventricule gauche chez 4 chatsCette série de cas décrit la résolution spontanée du mouvement antérieur systolique de la valve mitrale, la cessation d'une obstruction dynamique de la voie d'éjection du ventricule gauche et le remodelage cardiaque inverse chez 4 jeunes chats. Après une présentation initiale avec ou sans insuffisance cardiaque congestive, des vérifications ultérieures ont documenté la résolution du mouvement antérieur systolique de la valve mitrale et la normalisation des dimensions du cœur gauche. Les chats initialement présentés avec une insuffisance cardiaque congestive ont été sevrés avec succès des médicaments diurétiques. De l'aténolol a été prescrit aux 4 chats, et tous sont restés sous aténolol oral jusqu'au dernier contrôle. Aucune récidive de maladie cardiaque progressive et d'insuffisance cardiaque n'a été documentée chez aucun des chats. L'épaississement transitoire du myocarde, la résolution spontanée de la dysplasie de la valve mitrale et la réponse à l'antagonisme bêta-1 adrénergique sont pris en compte comme mécanismes sous-jacents possibles.Message clinique clé :Lorsqu'ils sont confrontés à de jeunes chats atteints de cardiomyopathie hypertrophique obstructive, les vétérinaires doivent envisager plusieurs diagnostics différentiels, car la durée de vie dans ces cas peut être plus longue que celle généralement attendue pour les chats atteints de cardiomyopathie hypertrophique primaire, même en cas d'insuffisance cardiaque congestive concomitante.(Traduit par Dr Serge Messier).

Inflammatory and immune variables as predictors of survival in dogs with myxomatous mitral valve disease.

BACKGROUND: We aimed to investigate the association between selected inflammatory and immune variables and survival of dogs with myxomatous mitral valve disease (MMVD). We evaluated data of 62 client-owned dogs with MMVD, grouped into preclinical, stable congestive heart failure (CHF) and unstable CHF. Univariate Cox proportional hazards regression analysis was used to quantify the association of white blood cell count, concentrations and percentages of T lymphocytes and their subtypes (T helper lymphocytes, cytotoxic T lymphocytes, double positive T lymphocytes, double negative T lymphocytes) and B lymphocytes with survival. P values < 0.1 in individual groups and P values < 0.05 in the group of all patients were considered significant. Spearman correlation coefficients between significant covariates were calculated to assess the relationships among variables and with survival. RESULTS: In the preclinical group, percentage of double positive T lymphocytes was negatively associated with survival (hazard ratio (HR) = 2.328; P = 0.051). In the unstable CHF, T lymphocyte (HR = 1.613; P = 0.085), cytotoxic T lymphocyte (HR = 1.562; P = 0.048), double positive (HR = 1.751; P = 0.042), and double negative T lymphocyte (HR = 1.613; P = 0.096) concentrations were negatively associated with survival, as well as cytotoxic T lymphocyte (HR = 1.502; P = 0.007) concentration in the group of all patients. The percentage of T helper lymphocytes was positively associated with survival in the unstable CHF (HR = 0.604; P = 0.053) and in the group of all patients (HR = 0.733; P = 0.044). The concentration of cytotoxic T lymphocytes positively correlated with left atrial to aortic ratio (LA/Ao) (rho = 0.259, P = 0.037), and peak velocity of early diastolic mitral flow (rho = 0.259, P = 0.039), whereas the percentage of T helper lymphocytes negatively correlated with left atrial to aortic ratio (LA/Ao) (rho = -0.212, P = 0.090) and early to late mitral flow ratio (rho = -0.232, P = 0.072). CONCLUSIONS: Cytotoxic T lymphocytes, T helper lymphocytes, double positive and double negative T lymphocytes as well as biomarkers cardiac troponin I, N-terminal pro-B-type natriuretic peptide, C-reactive protein are implicated in the progression of MMVD.

The association between taurine concentrations and dog characteristics, clinical variables, and diet in English cocker spaniels: The Canine taURinE (CURE) project.

BACKGROUND: Occurrence of low blood taurine concentrations (B-TauC) and predisposing factors to taurine deficiency in English Cocker Spaniels (ECS) are incompletely understood. OBJECTIVES: Investigate the occurrence of low B-TauC in a Swedish population of ECS and evaluate the association between B-TauC and dog characteristics, clinical variables, and diet composition. ANIMALS: One-hundred eighty privately owned ECS. METHODS: Dogs were prospectively recruited and underwent physical examination, blood analyses, and echocardiographic and ophthalmic examinations. Dogs with clinical signs of congestive heart failure (CHF) also underwent thoracic radiography. Taurine concentrations were analyzed in plasma (EDTA and heparin) and whole blood. Diets consumed by the dogs at the time of the examination were analyzed for dietary taurine- (D-TauC), cysteine- (D-CysC), and methionine concentrations (D-MetC). RESULTS: Fifty-three of 180 dogs (29%) had low B-TauC, of which 13 (25%) dogs had clinical and radiographic signs of CHF, increased echocardiographic left ventricular (LV) dimensions and volumes, and impaired LV systolic function. Five (9%) dogs with low B-TauC had retinal abnormalities. Dietary MetC, dietary animal protein source (red/white meat), and age were associated with B-TauC in the final multivariable regression model (P < .001, R2 adj = .39). CONCLUSIONS AND CLINICAL IMPORTANCE: Low B-TauC suggests that taurine deficiency may play a role in the development of myocardial failure and CHF in ECS. Low D-MetC and diets with red meat as the animal protein source were associated with low B-TauC. Dogs with B-TauC below the normal reference range were older than dogs with normal concentrations.

Reversible right-sided congestive heart failure secondary to primary hyperaldosteronism in a cat.

A 10-year-old male castrated Somali cat presented with neurologic signs, severe systemic hypertension, and hypokalemia. Abdominal ultrasonography demonstrated a left adrenal mass, and the serum aldosterone concentration was increased. Computed tomography and follow-up diagnostic testing confirmed a left adrenal mass consistent with functional adenocarcinoma; additional findings included chronic airway and parenchymal disease. Transthoracic echocardiography revealed biatrial enlargement, with abdominal and pericardial effusion, consistent with right-sided congestive heart failure. The cat was treated for congestive heart failure and adrenalectomy was performed. Cardiac structure and function returned to normal within 6 months postoperatively. This report highlights a case of reversible congestive heart failure secondary to primary hyperaldosteronism.

Assessment of right ventricular function in healthy Great Danes and in Great Danes with dilated cardiomyopathy.

INTRODUCTION: Right ventricular (RV) dysfunction is a significant negative prognostic indicator in human dilated cardiomyopathy (DCM). Many RV indices are weight-dependent, and there is a lack of reference values for the right heart in giant breed dogs (over 50 kg), including Great Danes (GDs). This study aimed to compare indices of RV function in echocardiographically normal GDs, those with preclinical DCM (PC-DCM), and those with DCM and congestive heart failure (DCM-CHF). ANIMALS: A total of 116 client-owned adult GDs: 74 normal, 31 with PC-DCM, and 11 with DCM-CHF. METHODS: A retrospective, single-center cohort study assessed RV function using free-wall RV longitudinal strain (RVLS), strain rate, fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE), and pulsed-wave tissue Doppler imaging-derived systolic myocardial velocity of the lateral tricuspid annulus (TDI S'). Relationships between DCM status and RV function indices were analyzed. RESULTS: RV function, measured by TAPSE (P=0.001), FAC (P<0.001), and TDI S' (P<0.001), decreased in dogs with PC-DCM and DCM-CHF compared to healthy dogs, with FAC being lower in DCM-CHF compared to PC-DCM (P=0.048). RVLS impairment was more significant in the DCM-CHF group than in the PC-DCM group (P=0.048). RVLS had the highest area under the curve (0.899) for differentiating between normal and DCM-CHF dogs. CONCLUSION: As DCM progresses, echocardiographic variables of RV function, including TAPSE, FAC, TDI S', RVLS, and strain rate, worsen, indicating impaired RV systolic function in GDs affected by DCM.

Potential prognostic indicators in dogs with advanced heart failure secondary to myxomatous mitral valve disease.

BACKGROUND: Advanced heart failure (AHF) secondary to myxomatous mitral valve disease (MMVD) in dogs has unclear predictive variables and survival time. METHODS: This retrospective study included 38 dogs with AHF and 38 with stable congestive heart failure (CHF), both due to MMVD. Predictive variables for AHF were analysed, and survival times were calculated using logistic regression and the Kaplan-Meier method. RESULTS: Left atrium to aortic root ratio, normalised left ventricular dimension at the end-diastole and end-systole, isovolumic relaxation time (IVRT) and early transmitral inflow velocity to IVRT ratio were associated with AHF progression. The median survival times were significantly longer in the stable group than in the AHF group. After AHF diagnosis, the median survival times for all-cause and cardiogenic mortality were 194 and 354 days, respectively. LIMITATIONS: This was a single-centre retrospective observational study. The study population was small, with breed bias (overrepresentation of Maltese dogs). Additionally, the treatment plans depended on clinical experience. CONCLUSIONS: AHF in dogs with CHF secondary to MMVD is linked to left heart chamber enlargement and increased left ventricular dimensions, significantly reducing survival time to around six months post-diagnosis. Early recognition and appropriate management may improve outcomes, highlighting the importance of advanced treatment strategies.

Retrospective analysis of dogs and cats with a mixed form of pulmonary hypertension and suspected pulmonary capillary hemangiomatosis in comparison to animals with predomination of precapillary pulmonary hypertension.

Background: Pulmonary capillary hemangiomatosis (PCH) is an idiopathic disease with the anomalous proliferation of a small capillary-like vessel in the pulmonary tissue, which can lead to a severe form of PH. There are only several cases of PCH described in veterinary literature: 27 cases in dogs and 2 cases in cats. In veterinary medicine, PH is mostly recognized as a consequence of left heart failure as a progression of the postcapillary PH to the precapillary form. PCH is mostly described as a primary disease, but resistant postcapillary PH with the high possibility of pulmonary edema raises speculation that PCH could be a secondary malformation to the left heart disease. Aim: Discover the features associated with the shift between left- and right-sided heart disease in the context of PH development. Methods: Retrospective analysis of materials from cats and dogs with histological markers of PCH (sPCH) versus those with right heart failure (RHF). Results: Animals with histological and immunohistochemistry markers of PCH had a previous history of disease with left heart volume overload. There were no differences between the groups in radiography and gross pathology. Histologically, pulmonary fibrosis and arteriopathy could be found in RHF; in sPCH-a duplication of capillaries in alveolar septa and bizarre proliferation in surrounding structures. Conclusion: PCH could be a secondary pattern of vascular remodeling due to volume overload.

Neutrophil-to-lymphocyte ratio and red blood cell distribution width to platelet ratio and their relationships with inflammatory and antioxidant status in dogs with different stages of heart failure due to myxomatous mitral valve disease.

We aimed to evaluate the red blood cell distribution width-to-platelet ratio (RDW/PLT) with other complete blood cell count (CBC) indices and their correlations with serum proinflammatory cytokines, acute phase proteins (APPs), and antioxidant biomarkers in dogs at different stages of heart failure (HF). A total of 29 dogs were divided into four groups according to the ACVIM Consensus Statement: stage-A (healthy/controls, n = 8), stage-B2 (n = 6), stage-C (n = 10), and stage-D (n = 5). Seventeen CBC indices were calculated and correlated with the measurements of inflammatory, APPs, and antioxidant biomarkers, as well as selected echocardiographic variables in all dogs. At stage-C, CBC indices were evaluated 14 days after the treatment. Statistically significant changes were observed only for RDW/PLT and neutrophil-to-lymphocyte ratio (NLR) between groups. NLR increased, but RDW/PLT deceased in dogs with HF, compared to controls (P < 0.05). There were no statistically differences between pre- and post-treatment CBC indices. There were significantly positive and negative correlations between the CBC indices, serum parameters and selected echocardiographic variables in dogs with HF(P < 0.05). ROC analysis showed the best sensitivity (57% and 68%) and specificity (100% and 57%) for NLR > 5.8 and RDW/PLT ≤ 0.057 for predicting the severity of HF, respectively. Results showed that NLR and RDW/PLT may have potential for monitoring severity of the disease and the effect of treatment in dogs with HF. Imbalances between indices of circulating blood cells can contribute to immunoinflammatory and antioxidant responses in pathogenesis of canine HF, which may provide us alternative targets to develop new diagnostic and therapeutic strategies in veterinary medicine.

Feline aortic thromboembolism with and without congestive heart failure did not exhibit hypercoagulability using a novel viscoelastic coagulation monitor.

OBJECTIVE: To demonstrate hypercoagulability with a benchtop viscoelastic monitor in cats with congestive heart failure (CHF) and/or aortic thromboembolism (ATE) compared to controls. METHODS: 97 cats were enrolled throughout this prospective observational cohort study from September 2022 through October 2023. Cats were grouped by diagnosis of CHF, ATE, ATE plus CHF, or controls. Enrollment required diagnosis of heart disease and no previous antithrombotic therapy. The results of viscoelastic testing with the benchtop viscoelastic coagulation monitor (VCM Vet [VCM]; Entegrion) were compared between groups using factorial analysis of variance. RESULTS: Cats with heart disease had significantly higher clot times when compared to controls (control: mean, 285.3 [SD, 172.6]; CHF: mean, 391.7 [SD, 106.8]; ATE: mean, 415.9 [SD, 109.2]; and ATE plus CHF: mean, 368.6 [SD, 232.6]). Heart disease cats were noted to have significantly lower 45-minute lysis index values (control: median, 100 [range, 93 to 100]; CHF: median, 99 [range, 89 to 100]; ATE: median, 98 [range, 88 to 100]; and ATE plus CHF: range, 98 [91 to 100]). Age was a covariate to this variable, and when applied to analysis, statistical significance was lost. No significant difference in any other variables were noted. CLINICAL RELEVANCE: The hypercoagulability of ATE and CHF cats was not detected by the VCM. Further research with other coagulation monitors is required in this population.

Retrospective evaluation of the utility of shock index to determine the presence of congestive heart failure in dogs with myxomatous mitral valve disease (2019-2021): 98 cases.

OBJECTIVES: To calculate the shock index (SI) in dogs with myxomatous mitral valve disease (MMVD) and to evaluate its use to predict the presence of congestive heart failure (CHF). DESIGN: Retrospective study. SETTING: Small animal university veterinary teaching hospital. ANIMALS: Ninety-eight dogs with MMVD and 20 healthy dogs as part of a control group. INTERVENTIONS: Heart rate (HR) and systolic blood pressure (SBP) were recorded, and SI was calculated by dividing HR by SBP for each dog. MEASUREMENTS AND MAIN RESULTS: The mean (SD) HR, SBP, and SI were 123/min (32.6), 147 mm Hg (21.5), and 0.86 (0.3), respectively, for dogs with MMVD and 98/min (20.9), 145 mm Hg (18.7), and 0.68 (0.13), respectively, for control dogs. Dogs with MMVD had a significantly higher HR compared with control dogs (P < 0.01), and an elevation in HR was seen as the severity of MMVD increased. Dogs in stage B2 and C/D MMVD had a significantly higher SI value compared with control dogs (P = 0.04 and P < 0.01, respectively). SI was significantly higher in dogs in stage C/D MMVD compared with dogs in stage B2 MMVD (P < 0.01). Ten of 98 (10%) dogs had an arrhythmia. HR, SBP, and SI were not significantly different between dogs with and without arrhythmias (P = 0.13, P = 0.57, and P = 0.07, respectively), but significantly more dogs with CHF had an arrhythmia (P = 0.01). SI (area under the curve [AUC]: 0.98) and HR (AUC: 0.95) were excellent indicators for the presence of CHF. An optimal SI cutoff value ≥1.1 had 92% sensitivity and 95% specificity for predicting the presence of CHF, and an optimal HR cutoff value of ≥157/min had 92% sensitivity and 93% specificity for the prediction of CHF. CONCLUSIONS: When there are compatible clinical signs, SI values ≥1.1 may suggest the presence of CHF in dogs with MMVD.

Bovine medicine: Whats´s your diagnosis?

INTRODUCTION: Two Angus calves housed in the Swiss Alps for two months were presented with brisket edema, jugular distension, and diarrhea. Hematological and biochemical examination included elevated concentration of erythrocytes and increased activity of liver enzymes. Ultrasonography revealed small amount of pleural effusion hepatomegaly and congested caudal vena cava. The diagnosis of congestive heart failure secondary to high-altitude disease was confirmed in pathology.

INTRODUCTION: Deux veaux Angus alpés dans les Alpes suisses depuis deux mois ont été présentés avec un œdème du poitrail, une stase jugulaire et de la diarrhée. Les examens hématologiques et biochimiques ont révélé une concentration élevée d'érythrocytes ainsi qu'une augmentation de l'activité des enzymes hépatiques. L'échographie a révélé un petit épanchement pleural, une hépatomégalie et une veine cave caudale congestionnée. Le diagnostic d'insuffisance cardiaque congestive secondaire à un mal des montagnes a été confirmé par la pathologie.

Transient myocardial thickening after routine ovariohysterectomy in a 15-month-old Ragdoll cat.

A 15-month-old female Ragdoll cat was evaluated for progressive lethargy, tachypnoea and increased respiratory effort for 1 week after routine ovariohysterectomy. Thoracic radiographs and an echocardiogram showed evidence of congestive heart failure and a hypertrophic cardiomyopathy phenotype, respectively. The maximum left ventricular wall thickness in end diastole was 6.2 mm. The serum cardiac troponin I concentration was 20.86 ng/mL. The cat was treated with furosemide and clopidogrel and discharged after 3 days. A repeat echocardiogram 2 weeks later showed complete resolution of the hypertrophic cardiomyopathy phenotype (maximum left ventricular wall thickness: 5.0 mm). A repeat cardiac troponin I concentration was 0.041 ng/mL. All cardiac medications were discontinued. A final recheck 4 weeks later revealed stable normal echocardiogram and further reduction in cardiac troponin I concentration to 0.004 ng/mL. This case report demonstrates that resolution of transient myocardial thickening can take 2 weeks after the echocardiographic diagnosis of left ventricular thickening.

Effects of acute atrial fibrillation and cardioversion on left and right atrial pressures in a dog.

The occurrence of right-sided congestive heart failure (CHF) in dogs with left-sided heart disease is well-recognized, but its mechanisms are incompletely understood. A 12-year-old Maltese dog was admitted to the clinic for left atrial decompression to treat recurrent CHF due to severe myxomatous mitral valve disease (MMVD). Left atrial decompression was successful but atrial fibrillation (AF) occurred during the procedure. Electric cardioversion restored normal sinus rhythm (NSR) and the dog's recovery was uneventful. This sequence of events made it possible to study intracameral pressures individually in each atrium in a dog with naturally occurring MMVD during AF and again during NSR. Although pressures in both atria declined following cardioversion, the right atrial pressure declined to a greater degree. These findings indicated a disproportionate effect of AF on right atrial pressure. This difference was noteworthy given the long-standing clinical observation that dogs with MMVD have a higher prevalence of right-sided CHF when AF is present. Key clinical message: A dog with MMVD had a greater reduction in right atrial pressure than in left atrial pressure when its AF was cardioverted as part of a cardiac catheterization procedure. This observation proposed a mechanism for the well-known but unexplained observation that dogs with MMVD manifest right-sided CHF disproportionately more often when they have AF.

Effets de la fibrillation auriculaire aiguë et de la cardioversion sur les pressions auriculaires gauche et droite chez un chien. La présence d'une insuffisance cardiaque congestive du côté droit (ICC) chez les chiens atteints d'une cardiopathie du côté gauche est bien connue, mais ses mécanismes ne sont pas complètement compris. Un chien maltais de 12 ans a été admis à la clinique pour une décompression auriculaire gauche afin de traiter une ICC récurrente due à une grave maladie myxomateuse de la valvule mitrale (MMVD). La décompression auriculaire gauche a réussi, mais une fibrillation auriculaire (FA) s'est produite pendant la procédure. La cardioversion électrique a rétabli le rythme sinusal normal (NSR) et la récupération du chien s'est déroulée sans incident. Cette séquence d'événements a permis d'étudier les pressions individuellement dans chaque oreillette chez un chien atteint de MMVD d'origine naturelle pendant la FA et à nouveau pendant la NSR. Bien que les pressions dans les deux oreillettes aient diminué après la cardioversion, la pression de l'oreillette droite a diminué dans une plus grande mesure. Ces résultats ont indiqué un effet disproportionné de la FA sur la pression auriculaire droite. Cette différence était remarquable compte tenu de l'observation clinique de longue date selon laquelle les chiens atteints de MMVD ont une prévalence plus élevée d'ICC du côté droit en cas de FA.Message clinique clé :Un chien atteint de MMVD présentait une réduction plus importante de la pression auriculaire droite que de la pression auriculaire gauche lorsque sa FA était cardiovertie dans le cadre d'une procédure de cathétérisme cardiaque. Cette observation propose un mécanisme pour l'observation bien connue mais inexpliquée selon laquelle les chiens atteints de MMVD manifestent une ICC du côté droit de manière disproportionnée plus souvent lorsqu'ils souffrent de FA.(Traduit par Dr Serge Messier).

Clinical effect of torsemide in a horse with congestive heart failure and atrial fibrillation.

In this case report, a high dose of torsemide (6mg/kg, every 12 hours for 3 days followed by 12mg/kg, every 12 hours for 4 days) was administered orally to a horse with congestive heart failure (CHF) and atrial fibrillation. Blood samples for measurement of plasma torsemide concentrations were obtained one hour after each drug administration. Pharmacodynamic effects of oral torsemide were evaluated by daily physical examination, electrocardiography, and serum biochemistry. The horse tolerated administration of torsemide. A decrease in ventral oedema and venous congestion was subjectively noted at day 7. Torsemide plasma concentration markedly increased at day 5 (peak concentration of 15.41 µg/mL). Evidence of an increase in renal markers was observed throughout the study period. Electrolyte measurements revealed mild hyponatremia and hypochloremia, and moderate hypokalaemia. No electrocardiographic changes related to torsemide administration were observed. After seven days of treatment, the horse was euthanised due to his disease stage and poor prognosis. Results indicate that torsemide was absorbed after oral administration and was well tolerated in this horse. Furthermore, clinical improvement in this single case indicates that torsemide might be utilized as an oral alternative to furosemide in the management of equine patients in CHF. The high doses of torsemide used in this case report should be reserved for cases without clinical response to lower doses and with close monitoring of electrolytes and renal function parameters. Further investigation of torsemide clinical efficacy and safety in horses with CHF with a larger cohort and prolonged administration is warranted.

Mitral valve transcriptome analysis in thirty-four age-matched Cavalier King Charles Spaniels with or without congestive heart failure caused by myxomatous mitral valve disease.

We here report the results of a mitral valve transcriptome study designed to identify genes and molecular pathways involved in development of congestive heart failure (CHF) following myxomatous mitral valve disease (MMVD) in dogs. The study is focused on a cohort of elderly age-matched dogs (n = 34, age ~ 10 years) from a single breed-Cavalier King Charles Spaniels (CKCS)-with a high incidence of MMVD. The cohort comprises 19 dogs (10♀, 9♂) without MMVD-associated CHF, and 15 dogs (6♀, 9♂) with CHF caused by MMVD; i.e., we compare gene expression in breed and age-matched groups of dogs, which only differ with respect to CHF status. We identify 56 genes, which are differentially expressed between the two groups. In this list of genes, we confirm an enrichment of genes related to the TNFß-signaling pathway, extracellular matrix organization, vascular development, and endothelium damage, which also have been identified in previous studies. However, the genes with the greatest difference in expression between the two groups are CNTN3 and MYH1. Both genes encode proteins, which are predicted to have an effect on the contractile activity of myocardial cells, which in turn may have an effect on valvular performance and hemodynamics across the mitral valve. This may result in shear forces with impact on MMVD progression.

Efficacy of a mitral regurgitation severity index to predict long-term outcome in dogs with myxomatous mitral valve disease.

BACKGROUND: Predicting progression of myxomatous mitral valve disease (MMVD) in dogs can be challenging. HYPOTHESIS/OBJECTIVES: The mitral regurgitation severity index (MRSI) will predict time to congestive heart failure (CHF) and all-cause death in dogs with MMVD. ANIMALS: Eight hundred sixty-nine client-owned dogs. METHODS: Retrospective study pooling data from 4 previous samples including dogs with MMVD stage B2 or C. MRSI was calculated as: (heart rate [HR]/120) × left atrium-to-aorta ratio (LA:Ao) × (age in years/10) × 100. Alternative MRSI formulas substituting radiographic measures of left atrial size were also calculated. Cox proportional hazard modeling and time-dependent receiver-operator characteristic curves quantified prognostic performance. RESULTS: For Stage B2 pooled samples, MRSI > 156 was predictive of time to CHF (median 407 vs 1404 days; area under the curve [AUC] 0.68; hazard ratio 3.02 [95% CI 1.9-4.9]; P < .001). MRSI > 173 was predictive of all-cause death (median survival 868 vs 1843 days; AUC 0.64; hazard ratio 4.26 [95% CI 2.4-7.5]; P < .001). MRSI showed superior predictive value compared to the individual variables of HR, LA:Ao, and age. Variations of the MRSI equation substituting radiographic vertebral left atrial size for LA:Ao were also significantly predictive of outcome in stage B2. MRSI was not consistently predictive of outcome in Stage C. CONCLUSIONS AND CLINICAL IMPORTANCE: MRSI was predictive of outcome (onset of CHF and all-cause death) in MMVD Stage B2, demonstrating utility as a useful prognostic tool. Echocardiographic LA:Ao can be effectively replaced by radiographically determined LA size in the MRSI formula.

Hypertrophic cardiomyopathy in a dog: a systematic diagnostic approach.

A seven-year-old female neutered Parson Russel terrier was referred for syncopal episodes. An electrocardiogram revealed paroxysmal atrial flutter followed by periods of sinus arrest, suggesting sick sinus syndrome. Echocardiography showed severe biventricular wall thickening (hypertrophic cardiomyopathy (HCM) phenotype) with no signs of fixed or dynamic left ventricular outflow tract obstruction. Blood pressure, abdominal ultrasound, serum total thyroxin and thyroid-stimulating hormone, and insulin-like growth factor-1 were all within normal limits. Cardiac troponin I was elevated (1.7 ng/mL, ref<0.07). Serological tests for common infectious diseases were negative. A 24-h Holter confirmed that the syncopal episodes were associated with asystolic pauses (sinus arrest after runs of atrial flutter) ranging between 8.5 and 9.6 s. Right ventricular endomyocardial biopsies (EMB) were performed at the time of pacemaker implantation to assess for storage or infiltrative diseases that mimic HCM in people. Histological analysis of the EMB revealed plurifocal inflammatory infiltrates with macrophages and lymphocytes (CD3+ > 7/mm2) associated with myocyte necrosis, but no evidence of myocyte vacuolisation or infiltrative myocardial disorders. These findings were compatible with myocardial ischaemic injury or acute lymphocytic myocarditis. Molecular analysis of canine cardiotropic viruses were negative. The dog developed refractory congestive heart failure and was euthanised 16 months later. Cardiac post-mortem examination revealed cardiomyocyte hypertrophy and disarray with diffuse interstitial and patchy replacement fibrosis, and small vessel disease, confirming HCM. We described a systemic diagnostic approach to an HCM phenotype in a dog, where a diagnosis of HCM was reached by excluding HCM phenocopies.

Clinical relevance of serum ionized magnesium concentration in dogs with myxomatous mitral valve disease.

BACKGROUND: Hypomagnesemia is associated with a poor prognosis in humans with congestive heart failure (CHF), but studies in veterinary medicine are limited. HYPOTHESIS: Serum ionized magnesium concentration [iMg2+ ] would decrease as CHF progresses compared with the initial diagnostic levels and that lower [iMg2+ ] would be negatively associated with prognosis in dogs with CHF. ANIMALS: A total of 181 client-owned dogs with myxomatous mitral valve disease (MMVD) were included. They were classified into the preclinical stage (NO-CHF, n = 108), stage C (n = 42), and stage D (n = 31) based on the American College of Veterinary Internal Medicine MMVD classification. METHODS: This is a retrospective study from 2 referral centers. The [iMg2+ ] was compared among the NO-CHF, stage C, and stage D groups. Kaplan-Meier curves and the log-rank test were used to compare the incidence of death between groups. Multivariable Cox regression analysis was used to estimate the association of hypomagnesemia with the death. RESULTS: In the stage D group, the [iMg2+ ] was lower than that in the NO-CHF (P < .0001) and stage C groups (P < .003). In the Kaplan-Meier survival analysis, the 1-year cumulative survival rate in hypomagnesemic dogs was 53% compared with 91.5% in normomagnesemic dogs (log-rank test, P < .0001). In the multivariable Cox analysis, lower concentration of [K+ ] and [iMg2+ ], along with higher Evel , were associated with negative prognoses. Specifically, hypomagnesemia was associated with an approximately 4-fold increased risk of death (hazard ratio = 4.015; 95% confidence interval, 1.537-10.488; P = .005). CONCLUSIONS AND CLINICAL IMPORTANCE: Assessing the [iMg2+ ] might serve as a potential marker for estimating the severity and prognosis indirectly in dogs with MMVD. Combining [iMg2+ ] measurement with other diagnostic methods, such as echocardiography, could improve the prognostic evaluation of MMVD in dogs.

Urine sodium concentration after intravenous furosemide in dogs with acute congestive heart failure and correlation with treatment efficacy.

BACKGROUND: Poor natriuresis is a potential marker of diuretic resistance in dogs with acute congestive heart failure (CHF) but little is known about the relationship between urine sodium concentration (uNa) and frequency of successful decongestion. Supplemental O2 is a common treatment in dogs with severe CHF. The time from start to discontinuation of supplemental O2 therapy (DCSO2 ) typically reflects the time course and ease of decongestion. HYPOTHESIS/OBJECTIVES: Urine Na concentration after IV administration of furosemide will be correlated with duration of treatment with supplemental O2 (timeO2 ) and the cumulative frequency of successful DCSO2 during hospitalization. ANIMALS: Fifty-one dogs with acute CHF. METHODS: Retrospective observational single center study. RESULTS: Dogs with low uNa had significantly longer mean timeO2 than dogs with high uNa (uNa <87 mmol/L, 24.2 ± 2.6 hours vs uNa ≥87 mmol/L, 16.6 ± 1.7 hours; P = .02). Low uNa was correlated with lower cumulative frequency of DCSO2 (12 hour, 28%; 24 hour, 42%; 36 hour, 73%) compared to high uNa (12 hour, 28%; 24 hour, 88%; 36 hour, 96%; P = .005). History of PO loop diuretics, low serum chloride concentration (sCl), and high PCV were associated with low uNa. Urine Na concentration outperformed other metrics of diuretic responsiveness including weight loss. CONCLUSIONS AND CLINICAL IMPORTANCE: Urine Na concentration after IV furosemide predicted timeO2 and cumulative frequency of DCSO2 in dogs with acute CHF, which likely reflects important aspects of diuretic responsiveness. Urine Na can assess diuretic responsiveness and treatment efficacy in dogs with CHF.

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.