Gossypol toxicosis in a herd of beef calves

A 6-month-old crossbred calf was examined as representative of a herd of calves experiencing dyspnea and death, with few other clinical signs of illness. Physical examination of the calf identified pleural and peritoneal effusion and poor body condition. The calf did not respond to supportive treatment, and necropsy of it and another calf from the herd identified congestive heart failure as the cause of death. Gossypol toxicosis was the cause of congestive heart failure in this herd; the source of the toxin was a cottonseed meal and cottonseed hull ration fed by the owner.     

Prospective clinical evaluation of serum cardiac troponin T in dogs admitted to a veterinary teaching hospital

The purpose of this study was to measure serum cardiac troponin T (cTnT) with a commercially available human enzyme-linked immunoassay (ELISA) test in various groups of dogs, including those undergoing doxorubicin chemotherapy. Serum samples were obtained from 6 groups of dogs: (1) normal adult dogs (n = 15); (2) dogs with asymptomatic dilated cardiomyopathy (n = 5); (3) dogs with congestive heart failure (n = 10); (4) dogs with untreated neoplasia (n = 20); (5) dogs with skeletal muscle trauma (n = 10); and (6) dogs with neoplasia receiving doxorubicin chemotherapy (n = 4). One serum sample was obtained from each of the normal dogs, those with asymptomatic cardiomyopathy, those with congestive heart failure, and those with untreated neoplasia. Serum samples were obtained serially from the dogs that were undergoing doxorubicin chemotherapy; samples were collected before doxorubicin (30 mg/m2) administration and then 1, 5, 7, and 14 days after administration throughout 6 cycles for a cumulative total dose of 180 mg/m2. All normal dogs, dogs with untreated neoplasia, and dogs with asymptomatic dilated cardiomyopathy had cTnT concentrations below the lower limits of detection for the assay used (<0.05 ng/mL). Detectable concentrations of cTnT were found in 3 dogs with congestive heart failure and in 2 dogs with skeletal muscle trauma. Detectable concentrations also were found in both dogs that had received 180 mg/m2 of doxorubicin. We conclude that dogs with congestive heart failure and those with skeletal muscle trauma and dogs with neoplasia receiving high-dose doxorubicin chemotherapy may have increased serum cTnT concentration, which may be suggestive of myocardial damage.     

Atrial natriuretic peptide concentration in dogs with congestive heart failure, chronic renal failure, and hyperadrenocorticism.

The function of atrial natriuretic peptide (ANP) is claimed to be control of salt and water homeostasis, and thus, the hormone may be involved in the pathogenesis of certain diseases with impaired volume regulation. We, therefore, studied plasma ANP concentration in dogs with chronic renal failure, congestive heart failure, and hyperadrenocorticism. Dogs with chronic renal failure had twofold higher plasma ANP concentration (16.2 +/- 5.8 fmol/ml), compared with healthy dogs (8.3 +/- 3.5 fmol/ml). An even more distinct increase (sixfold) of plasma ANP concentration was found in dogs with congestive heart failure (52.9 +/- 29.7 fmol/ml). In contrast, dogs with hyperadrenocorticism did not have high ANP plasma concentration (5.5 +/- 2.0 fmol/ml). High-performance liquid chromatographic analysis of plasma from dogs with congestive heart failure indicated that, in addition to the normal circulating form of ANP (99-126), the unprocessed precursor ANP (1-126) is detectable in the circulation. These qualitative and quantitative alterations of plasma ANP concentration in dogs further suggest involvement of this peptide in the development and/or maintenance of diseases associated with impaired volume regulation.     

Doxorubicin-lnduced Cardiotoxicosis Clinical Features in 32 Dogs

Clinical cardiac abnormalities developed in 32 of 175 dogs that had various malignancies and were treated with doxorubicin: 31 dogs had electrocardiographic abnormalities including arrhythmias and nonspecific alterations in the R wave, ST segment, or QRS duration and 7 dogs had congestive heart failure. All seven dogs that had congestive heart failure died within 90 days. At necropsy, 13 of 32 affected dogs had noninflammatory myocardial degeneration, myocytolysis, vacuolation, and/or fibrosis and there was intramural coronary arteriosclerosis in all 13. Five dogs with lymphosarcoma were in complete clinical remission when they died of doxorubicin-induced cardiomyopathy, but the overall survival times of the lymphosarcoma subset was nevertheless longer than in previous studies. The clinical use of doxorubicin in the dog can cause cardiotoxicosis but the therapeutic benefit appears to outweigh risks in most dogs.     

An update on treatment and prognostic indicators in canine myxomatous mitral valve disease

Mitral regurgitation caused by myxomatous mitral valve disease is the most common cause for congestive heart failure and cardiac-related mortality in dogs. Typically, it takes several years for the disease to progress from mild, clinically silent myxomatous mitral valve disease to severe disease with signs of congestive heart failure. A proportion of dogs will never progress into congestive heart failure before they die from other causes or old age. Some variables have been shown to be predictive of onset of congestive heart failure and they might be useful to identify dogs that need more frequent monitoring and eventually treatment. Results from several controlled clinical trials are available concerning medical treatment of dogs with myxomatous mitral valve disease with or without congestive heart failure. These trials provide estimates of treatment effects and also allow identification of other variables with prognostic value for the outcome after the onset of congestive heart failure. Use of prognostic variables together with qualitative and quantitative results from clinical drug trials may aid the clinician and owner to plan and decide on optimal management of the myxomatous mitral valve disease dog. The purpose of this article is to review the current knowledge of prognostic variables and therapy for this common condition in dogs.     

Evaluation of circulating amino terminal-pro-B-type natriuretic peptide concentration in dogs with respiratory distress attributable to congestive heart failure or primary pulmonary disease

OBJECTIVE: To evaluate assessment of circulating amino terminal-pro-B-type natriuretic peptide (NT-proBNP) concentration as a means to discriminate between congestive heart failure and primary pulmonary disease in dogs. DESIGN: Prospective case series. ANIMALS: 46 dogs with signs of respiratory distress or coughing. PROCEDURES: All dogs underwent physical and thoracic radiographic examinations. Dogs with evidence of heart disease (eg, murmur, arrhythmia, or large cardiac silhouette detected by radiography) also underwent echocardiography. Dogs with no evidence of heart disease or failure were included if they underwent bronchoalveolar lavage (with cytologic examination and bacterial culture of the lavage fluid). Blood samples for NT-proBNP assay were obtained within 12 hours of the diagnosis of heart failure or prior to bronchoalveolar lavage in dogs with primary pulmonary disease. Circulating concentrations of NT-proBNP were compared between groups and correlated with radiographic and echocardiographic measures of cardiac size. RESULTS: Congestive heart failure and primary pulmonary disease were diagnosed in 25 and 21 dogs, respectively. Dogs with congestive heart failure had significantly higher median serum or plasma NT-proBNP concentration (2,554 pmol/L; interquartile [25% to 75%] range, 1,651.5 to 3,475.5 pmol/L) than dogs with primary pulmonary disease (357 pmol/L; interquartile range, 192.5 to 565.5 pmol/L). Radiographic vertebral heart score and echocardiographic left atrial-to-aortic diameter ratio were not correlated with NT-proBNP concentration. Left ventricular end-diastolic diameter (measured echocardiographically) and NT-proBNP concentration were weakly correlated. CONCLUSIONS AND CLINICAL RELEVANCE: Serum or plasma NT-proBNP concentration assessment may be useful for discrimination of congestive heart failure from primary pulmonary disease in dogs with respiratory distress or cough.     

The Effect of Combined Therapy With Captopril, Furosemide, and a Sodium-Restricted Diet on Serum Electrolyte Concentrations and Renal Function in Normal Dogs and Dogs With Congestive Heart Failure

Captopril, furosemide, and a sodium-restricted diet were administered to 6 normal dogs and 10 dogs with congestive heart failure. Serum electrolyte concentrations and renal function were monitored in both groups. In the normal dogs, no clinically meaningful changes in serum electrolyte, urea nitrogen, or creatinine concentrations developed during therapy with a sodium-restricted diet and 4 weeks each of furosemide alone, captopril alone, or furosemide plus captopril. Three of 6 normal dogs on furosemide and a sodium-restricted diet had at least one serum potassium concentration above the reference range during the 4 weeks of observation. One normal dog on captopril, furosemide, and a sodium-restricted diet developed azotemia, and 2 dogs had serum potassium concentrations above the reference range during the 4 weeks of observation. Ten dogs with congestive heart failure were treated with captopril, furosemide, a sodium-restricted diet, and digoxin.
Etiopathogenesis of the heart failure included valvular insufficiency (n = 6), dilated cardiomyopathy (n = 3), and dilated cardiomyopathy and dirofilariasis (n = 1). Serum electrolyte concentrations and renal function were monitored for 5 consecutive weeks in 7 of the 10 dogs and for 17 weeks or longer in 6. Two dogs were euthanized after 4 weeks because of acute decompensation of heart failure, and one dog developed severe azotemia and uremia. Six of 10 dogs with congestive heart failure had at least one serum potassium concentration above the reference range sometime during the 5 weeks of observation, although the changes in the mean serum potassium concentrations were not statistically significant. Four of 10 dogs with congestive heart failure developed azotemia sometime during the 5 weeks of observation.     

Ischaemic heart disease in the dog: a review of 65 cases

Sixty-five dogs are reviewed with histopathologically confirmed intramural arteriosclerosis. Clinical data (clinical signs, electrocardiographic findings and ultrasound parameters) on these animals were collected from nine small animal clinics in Sweden: 16 dogs had died suddenly, with few or no previous clinical signs; 13 dogs died or were euthanased during or shortly after general anaesthesia or sedation; 30 dogs developed acute (14) or chronic (16) congestive heart failure; and six dogs died or were euthanased for causes unrelated to cardiac disease. Electrocardiography of 23 of the dogs revealed several types of arrhythmias, with atrial fibrillation and sinus tachycardia being most commonly detected. Ultrasonographic examinations of 24 dogs found a relatively high number (19) with decreased indices of contractility. Dogs that had died suddenly and in relation to general anaesthesia or sedation had a higher incidence (25 of 29) of purely arteriosclerotic changes in the myocardial vessels, whereas just over half the dogs with congestive heart failure (16 of 30) had other concomitant heart lesions (in most cases endocardiosis). The incidence of myocardial infarcts was high (51 of 65 cases). It is postulated that arteriosclerosis in the dog may be an important reason for sudden death and death during general anaesthesia. Coronary arterial disease should also be a consideration in the clinical evaluation of dilated cardiomyopathy and may contribute to the decreased myocardial contractility when it is present in dogs with mitral regurgitation.     

A retrospective study of heart disease in doberman pinscher dogs

The prevalence of gross and/or histological cardiac lesions was found to be much greater in Doberman pinscher dogs (16/26 or 62%) than in non-Doberman dogs (124/417 or 30%). At least some of the affected Dobermans were unrelated. Middle aged (mean age 4.7 yr) Dobermans of both sexes (11 M:5F) were affected. Four of the Dobermans with heart lesions had congestive cardiomyopathy; three of these four had congestive heart failure and the other one died suddenly. Prominent gross lesions were ventricular dilation and atrioventricular valvular endocardiosis. Histological lesions noted were prominent myocardial fibrosis, myofiber degeneration with fatty replacement, myofiber vacuolation and arterial intimal cushion formation. A spectrum of myocardial disease exists in Dobermans and clinically overt congestive cardiomyopathy represents one end of this spectrum.     

Thyroid function in dogs with spontaneous and induced congestive heart failure.

The effects of spontaneous and experimentally induced congestive heart failure on serum thyroxine (T4), 3,5,3'-triiodothyronine (T3), 3,3'5'-triiodothyronine (reverse T3), free T4, free T3 concentrations, and the serum T4 and T3 concentrations in response to administration of thyrotropin were studied. Serum thyroid hormone concentrations were not different between eight dogs with spontaneous congestive heart failure and normal age matched control dogs. Seven dogs with experimental heart failure were tested before and after induction of congestive heart failure by rapid ventricular pacing. Mean serum T4 and free T3 concentrations were decreased and mean serum reverse T3 concentration was increased following induction of heart failure. The serum T4 and T3 responses to thyrotropin were not altered. Thyroid gland morphology appeared normal in dogs with experimental heart failure. Experimental congestive heart failure, similar to some other nonthyroidal illnesses, alters thyroid hormone secretion and metabolism in dogs.     

Rate of change of heart size before congestive heart failure in dogs with mitral regurgitation

Objectives : The objective of the study was to examine the changes in vertebral heart scale, and left atrial and ventricular dimensions before and at onset of congestive heart failure in cavalier King Charles spaniels with mitral regurgitation. Methods : Records and radiographs from 24 cavalier King Charles spaniels with mitral regurgitation were used. Vertebral heart scale (24 dogs), and left atrial dimension and left ventricular end diastolic and end systolic diameters (18 dogs) and their rate of increase were measured at intervals over years to the onset of congestive heart failure. They were plotted against time to onset of congestive heart failure. Results : Dimensions and rates of change of all parameters were highest at onset of congestive heart failure, the difference between observed and chance outcome being highly significant using a two-tailed chi-square test (P<0·001). Clinical significance : The left heart chambers increase in size rapidly only in the last year before the onset of congestive heart failure. Increasing left ventricular end systolic dimension is suggestive of myocardial failure before the onset of congestive heart failure. Rate of increase of heart dimensions may be a useful indicator of impending congestive heart failure.     

Use of a modified open patch-graft technique and valvulectomy for correction of severe pulmonic stenosis in dogs: eight consecutive cases

SUMMARY A modified open patch-graft technique was used to correct congenital pulmonic stenosis in 8 dogs. Pulmonary valve dysplasia was moderate to severe in all cases, based upon clinical and echocardiographic criteria, and 3 dogs were in right-sided congestive heart failure at the time of surgery. Seven of the 8 dogs survived the surgery. One surviving dog displayed cerebral cortical dysfunction, the remaining 6 had no detectable neurological sequelae. Right ventricular failure was alleviated in all 7 surviving dogs, but right ventricular dilatation persisted post-operatively. Pulmonary valvulectomy and open patch-grafting provides an effective means of alleviating signs of congestive heart failure caused by pulmonary valve dysplasia, even In the presence of severe infundibular hypertrophy and dynamic outflow obstruction.     

Echocardiographic and clinical signs of canine dilated cardiomyopathy

The clinical signs, electrocardiograms and echocardiograms of 12 dogs with dilated cardiomyopathy of large breeds and congestive heart failure were reviewed. There was a high prevalence of males (11 dogs) and of the Doberman breed (7 dogs). Seven dogs had atrial fibrillation. The echocardiograms revealed significant increases in left ventricular and left atrial dimensions. The shortening fraction (%ΔD), aortic root excursion and left ventricular wall excursion were all significantly decreased, documenting a decrease in contractile function of the left ventricle that, together with the cardiac enlargement characterize this disease. The advantages of obtaining these functional parameters non-invasively are emphasized.     

Congestive cardiac failure in young Cocker Spaniels (a form of cardiomyopathy?): details of eight cases

Eight cases are described of young Cocker Spaniels with severe congestive heart failure that fulfil the criteria for a diagnosis of congestive cardiomyopathy. The differential diagnosis of cardiomyopathy and primary mitral/tricuspid valve disease is discussed. Clinical, radiographic, electro-cardiographic, therapeutic and pathological details are reported. An analysis of pedigree records revealed a close ancestral relationship between six of the dogs.     

Canine hypertrophic cardiomyopathy.

Necropsy findings in 10 dogs with naturally occurring cardiac disease closely resembled hypertrophic cardiomyopathy in human beings and cats. Each dog had marked cardiac hypertrophy, and 8 dogs had disproportionate thickening of the ventricular septum with respect to the left ventricular free wall (compared with dogs with normal hearts or with cardiac hypertrophy due to acquired or congenital heart disease). Ratios of septum to free wall thickness in the 10 dogs ranged from 1.1 to 1.5, and 6 had ratios greater than or equal to 1.3. Marked cardiac muscle cell disorganization in the ventricular septum, characteristic of human patients with hypertrophic cardiomyopathy, was found in only 2 of the 10 dogs. Death occurred while the dogs were under anesthesia during the course of operative procedures (5 dogs) or unexpectedly in animals without previous manifestations of cardiac disease (3 dogs). Four dogs had clinical signs of congestive heart failure, including 2 with marked cardiac decompensation. Two of these 4 dogs with heart failure and 1 dog that died during unrelated surgery, but without prior signs of heart disease, had electrocardiographic evidence of complete heart block.     

Association between exogenous atrial natriuretic peptide and hemodynamics in dogs with congestive heart failure produced by experimental mitral regurgitation

Association between exogenous atrial natriuretic peptide (ANP) and hemodynamic changes was ascertained in 3 dogs with overt congestive heart failure (CHF(+)) and 3 dogs without congestive heart failure (CHF(-)) caused by experimental mitral regurgitation (MR). The hemodynamic measurements were recorded in all dogs during and after 1 hr infusion of ANP at the rate of 0.1 (low dose), 0.5 (medium dose) and 1.0 (high dose) microg/kg/min, respectively. Heart rate, mean arterial pressure, pulmonary capillary wedge pressure (PCWP) and systemic vascular resistance decreased significantly during and after ANP infusion even with low dose in the CHF(+). Stroke volume, stroke volume index and cardiac output in the CHF(+) during and after ANP infusion showed an increasing trend as compared with the CHF(-). Double product, an indicator of myocardial oxygen consumption, significantly decreased during and after ANP administration at all doses in the CHF(+). These findings indicate that even at low dose, exogenous ANP improves cardiac performance and reduces myocardial oxygen consumption in the CHF(+), and suggest that ANP has beneficial effects in the treatment of dogs with overt congestive heart failure resulting from MR.     

Lack of efficacy of low-dose spironolactone as adjunct treatment to conventional congestive heart failure treatment in dogs

Aldosterone plays an important role in the pathophysiology of heart failure. Aldosterone receptor blockade has been shown to reduce morbidity and mortality in human patients with advanced congestive left ventricular heart failure. This study was designed to assess the efficacy and tolerance of long-term low-dose spironolactone when added to conventional heart failure treatment in dogs with advanced heart failure. Eighteen client-owned dogs with advanced congestive heart failure due to either degenerative valve disease (n=11) or dilated cardiomyopathy (n=7) were included in this prospective, placebo-controlled, double-blinded, randomized clinical study. After initial stabilization including furosemide, angiotensin-converting enzyme inhibitors, pimobendan and digoxin, spironolactone at a median dose of 0.52 mg/kg (range 0.49-0.8 mg/kg) once daily (n=9) or placebo (n=9) was added to the treatment, and the dogs were reassessed 3 and 6 months later. Clinical scoring, echocardiography, electrocardiogram, systolic blood pressure measurement, thoracic radiography, sodium, potassium, urea, creatinine, alanine aminotransferase, aldosterone and aminoterminal atrial natriuretic propeptide were assessed at baseline, 3 and 6 months. Survival times were not significantly different between the two treatment groups. Spironolactone was well tolerated when combined with conventional heart failure treatment.     

C-reactive protein concentration in dogs with chronic valvular disease

The purpose of the study reported here was to determine whether dogs with chronic valvular disease have increased plasma C-reactive protein concentration, compared with that in clinically normal dogs. Blood was collected from 47 dogs with physical and echocardiographic evidence of chronic valvular disease and from 20 healthy controls. C-reactive protein concentration was determined with a commercial canine C-reactive protein enzyme immunoassay. Compared with controls, dogs with chronic valvular disease had higher plasma concentration of C-reactive protein (median 2.17 microg/mL [range, 0.86-33.8 microg/mL]) versus 1.43 microg/mL [range, 0.84-4.99 microg/mL]; P < .001). C-reactive protein concentration was not related to the presence of congestive heart failure or murmur grade. The results of this study suggest that increased concentration of C-reactive protein is found in dogs with chronic valvular disease.     

The prevalence of cardiomyopathy in the Irish wolfhound: a clinical study of 500 dogs

The prevalence of cardiomyopathy in Irish wolfhounds was evaluated by retrospective review of the results of cardiovascular examinations carried out in 500 dogs presented for veterinary services at the author's practice. Abnormalities were found in 209 (41.8%) of the dogs examined. Dilated cardiomyopathy (DCM) was diagnosed in 121 (24.2%) of the dogs and was accompanied by atrial fibrillation in 106 dogs. Seventeen dogs were suffering from advanced congestive heart failure (CHF), and 55 dogs were suffering from mild to moderate CHF as a result of DCM. Congestive heart failure was most commonly characterized by mild to severe pleural effusion due to right-sided heart failure in addition to pulmonary edema. Rhythm disturbances without evidence of DCM were detected in 48 dogs. Forty dogs had echocardiographic abnormalities without signs of DCM. Soft to moderate mitral regurgitations were diagnosed in 13 (2.6%) of these 40 dogs examined. In 39 dogs that died as a result of DCM, the median survival time from the time of diagnosis was 5.1 months, and in 59 dogs with DCM that are still alive, the median survival time is 15.7 months.     

Differences between breeds of dog in a measure of heart rate variability

The vasovagal tonus index (VVTI), a time-domain indicator of heart rate variability, was measured in 92 dogs of six breeds (German shepherd dogs, labrador retrievers, cocker spaniels, boxers, bulldogs and cavalier King Charles spaniels). There was a significant difference in VVTI between the six breeds (P = 0.003). Brachycephalic dogs had a higher VVTI than other types of dog (P < 0.005), and when comparing individual breeds brachycephalic breeds tended to have a higher VVTI than non-brachycephalic breeds, although the difference was not always significant. The VVTI was negatively correlated with heart rate (P < 0.01) and dogs suffering from congestive heart failure had a lower VVTI than other dogs, whether compared within or between breeds (P < 0.01).