A case of juvenile form of dilated cardiomyopathy in a 6-month-old Shiba Inu dog

A 6-month-old Shiba Inu dog was brought to the Veterinary Medical Teaching Hospital because of a cough, exercise intolerance, and pulmonary edema. The dog had a Levine 2/6 systolic murmur. Transthoracic echocardiography revealed left atrial and ventricular dilatation (left atrium to aortic ratio: 2.8), mitral and tricuspid valve regurgitation, and severe left ventricular myocardial hypokinesia (fractional shortening was 11.8%). Bubble contrast echocardiography did not reveal a congenital shunt; therefore, the dog was clinically diagnosed with early onset dilated cardiomyopathy. From the first visit, the dog was treated with pimobendan, taurine, torasemide, and isosorbide dinitrate. After 435 days, echocardiography revealed that systolic function had not improved. On Day 465, atrial fibrillation was confirmed via electrocardiogram, and treatment with diltiazem hydrochloride was initiated. The dog continued to appear clinically stable thereafter, until it died suddenly 1087 days after the initial visit. A postmortem histopathological examination identified severe enlargement of the left atrial and ventricular chambers as well as attenuated wavy fibers in the ventricular myocardium, which confirmed dilated cardiomyopathy in a juvenile. This is the first report of a juvenile form of dilated cardiomyopathy in a Shiba Inu dog. This case report provides evidence that the extended prognosis of this dog differed from that in previously reported cases of dilated cardiomyopathy in young dogs.Key clinical message:This is the first reported case of a juvenile form of dilated cardiomyopathy in a Shiba Inu dog. This report provides evidence that the prognosis of this dog differed from that in previously reported cases of dilated cardiomyopathy in young dogs.     

Clinical and pathological observations in English cocker spaniels with primary metabolic vitamin E deficiency and retinal pigment epithelial dystrophy

Fifteen English cocker spaniels with confirmed vitamin E deficiency were examined physically, ophthalmologically and neurologically. Eleven of them had clinical signs of neurological dysfunction which included ataxia, proprioceptive deficits, abnormal spinal reflexes and muscle weakness. In the two dogs examined histopathologically there was central neuronal fibre degeneration with prominent neuroaxonal dystrophy, particularly within the sensory relay nuclei of the brainstem, and one of the dogs had severe intestinal lipofuscinosis.     

Heart rate variability in relation to severity of mitral regurgitation in Cavalier King Charles spaniels

Heart rate variability was measured in 81 Cavalier King Charles spaniels to investigate if it could be used to evaluate the severity of mitral regurgitation and to predict decompensation. Heart rate variability was assessed by the natural logarithm of the variance of the R-R intervals for 20 consecutive beats obtained from electrocardiographic recordings. Twenty-two of the dogs were clinically normal and 59 had mitral regurgitation caused by chronic valvular disease. The severity of mitral regurgitation was evaluated by echocardiography and thoracic radiography. Heart rate variability was found to be reduced (P < 0.001) among dogs with severe left atrial and ventricular dilatation and clinical signs of congestion. No significant differences in heart rate variability were found among normal dogs, dogs with only cardiac murmur, and dogs with echocardiographic evidence of slight to moderate left atrial and ventricular dilatation. Overall, an association was found between heart rate variability and left atrial to aortic root ratio and left ventricular end diastolic diameters (r = 0.72 and 0.64, respectively, P < 0.001), as well as heart and respiratory rate (r = 0.80 and 0.69, respectively, P < 0.001). Multiregression analysis showed that, in order of importance, heart rate, left atrial diameter and respiratory rate had significant effects on heart rate variability. Among these parameters, heart rate variability and left atrial diameter were found to be most efficient in separating decompensated dogs from compensated. It is concluded that heart rate variability may provide the clinician with valuable information when assessing the severity of mitral regurgitation caused by chronic valvular disease.     

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.     

MITRAL ANNULUS MOTION AS DETERMINED BY M-MODE ECHOCARDIOGRAPHY IN NORMAL DOGS AND DOGS WITH CARDIAC DISEASE

M-mode echocardiography was used to assess apical mitral annulus motion (MAM) in 103 normal dogs and 101 dogs with cardiac disease, to obtain information on systolic left ventricular long axis function. In normal dogs, a close relationship was found between MAM and body weight (r = 0.80, P < 0.001). There was a weak correlation between MAM and heart rate (r = -0.25, P < 0.05), but no correlation between MAM and age or left ventricular shortening fraction (P > 0.05). Mean MAM (95% confidence intervals) were established for normal dogs of differing body weight, and were 0.70 cm (0.65 to 0.75) in dogs < 15 kg, 1.08 cm (1.03 to 1.13) in dogs weighing 15 to 40 kg, and 1.51 cm (1.21 to 1.81) in dogs > 40 kg. "Cut-off" values to define decreased MAM for normal dogs of differing body weight were 0.45 cm (dogs < 15 kg), 0.80 cm (dogs 15-40 kg), and 1.20 cm (dogs > 40 kg). In dogs with cardiac disease, median MAM was normal in mitral valve endocardiosis or aortic stenosis, but significantly decreased (P < 0.05) in dilated cardiomyopathy. All dogs with mitral valve endocardiosis (n = 54) or aortic stenosis (n = 26) had MAM above the above-mentioned "cut-off" values, suggesting normal or increased left ventricular longitudinal systolic shortening, whereas 81% (17/21) of dogs with dilated cardiomyopathy had MAM below the "cut-off" value, indicating decreased long axis systolic function. It is concluded that MAM may be used to evaluate systolic left ventricular long axis performance in dogs and may add useful information on global left ventricular contraction dynamics.     

Incomplete Ossification of the Humeral Condyle in Spaniels

An evaluation of 157 dogs with humeral fractures was performed. Cocker spaniels were more likely to have humeral condylar fractures (HCFs) than other breeds ( P < .0001). Male cocker spaniels were at increased risk ( P < .001). Cocker spaniels had more bilateral HCFs than other breeds of dogs ( P < .001). Eighteen dogs (17 purebred spaniels and 1 crossbred spaniel) with HCFs of unknown cause or occurring with normal activity were further studied, using radiography of their humeral condyle bilaterally (n = 18), computed tomography (n = 3), biopsy (n = 2), bone scintigraphy (n = 2), and genetic evaluation (n = 8). Fourteen of these 18 dogs had a nonfractured contralateral condyle. Twelve (86%) of the 14 nonfractured humeral condyles had a radiolucent line within the center of the condyle, 13 (93%) had radiographic signs of degenerative joint disease and an abnormal medial coronoid process, and six (43%) had periosteal proliferation involving the lateral epicondyle. Examination of biopsy samples from the fracture sites of two cocker spaniels showed fibrous tissue present at the fracture surfaces. The results of this study suggest an association between incomplete ossification of the humeral condyle in cocker spaniels and Brittany spaniels and a high prevalence of HCFs. Eight affected cocker spaniels with available pedigree information were found to be genetically related, suggesting that incomplete ossification of the humeral condyle may be a genetic disease with a recessive mode of inheritance.     

Echocardiographic evaluation of diastolic parameters in dogs with dilated cardiomyopathy

Echocardiography is a valuable tool for the evaluation of systolic and diastolic cardiac function. A high correlation between measurements of diastolic mitral inflow parameters analyzed with Doppler echocardiography and invasive methods makes the former valuable. The aim of this study was to ascertain if significant differences occur in diastolic myocardial parameters between dogs with no heart disease and dogs with subclinical or clinical dilated cardiomyopathy. Furthermore the aim of the study was to determine whether heart failure in dilated cardiomypathy is a result of systolic dysfunction alone or both systolic and diastolic dysfunction. Eleven parameters were analyzed: E wave, E-AT, E-DT, E time, A wave, A-AT, A-DT, A time, E+A time, E/A ratio, and IVRT. The study confirmed the value of noninvasive echocardiographic assessment of diastolic function in dogs with dilated cardiomyopathy. Significant differences were found in E wave, E-AT, E time, E/A ratio and IVRT between healthy dogs and dogs with dilated cardiomyopathy. All are characterized by a significant decrease compared to healthy dogs after taking into account age and body weight except for the E/A ratio, which significantly increased in value. There were no significant changes in any of the Doppler parameters for diastolic evaluation in subclinical cases of DCM. Advanced heart failure in dilated cardiomyopathy entails systolic and diastolic dysfunction.     

Effect of severity of myocardial failure on heart rate variability in Doberman pinschers with and without echocardiographic evidence of dilated cardiomyopathy.

OBJECTIVE: To determine whether heart rate variability (HRV) is reduced in Doberman Pinschers with dilated cardiomyopathy. DESIGN: Case series. ANIMALS: 62 overtly healthy Doberman pinschers. PROCEDURE: Heart rate variability was analyzed in time and frequency domains from data obtained during 24-hour ambulatory electrocardiographic Holter recordings in 41 overtly healthy Doberman pinschers with normal echocardiograms and 21 overtly healthy Doberman pinschers with abnormal echocardiograms. RESULTS: Heart rate variability usually was greater during night versus day, and 2 dogs with the most severe myocardial failure had reduced HRV. CONCLUSIONS AND CLINICAL RELEVANCE: Reduced HRV was detected only in Doberman Pinschers with the most severe myocardial failure. Thus, HRV in less severely affected dogs is not reduced, or the normal sinus arrhythmia of dogs renders HRV relatively insensitive. Analysis of HRV did not provide additional information relative to the severity of left ventricular dysfunction or risk of sudden death from that which could be derived from echocardiography, analysis of Holter recordings, and signal-averaged electrocardiography.     

Breed, age and gender distribution of dogs with chronic hepatitis in the United Kingdom

Standardised histological criteria are now available for the diagnosis of canine chronic hepatitis (CH). CH is common in dogs, but no studies have reported breed, age and gender distributions in the United Kingdom (UK). The objective of this study was to determine which breeds had an increased risk for developing CH in the UK and to report the age and gender distribution for those breeds. The databases of six veterinary histopathology laboratories were searched for cases with a histological diagnosis of CH according to standardised criteria. The breed, age and gender of dogs was recorded and compared to a control population to calculate the odds ratio and 95% confidence intervals for developing CH. A total of 551 cases of CH were identified, consisting of 61 breeds. Nineteen breeds were represented by five or more cases. Breeds with an increased risk for developing CH included the American cocker spaniel, Cairn terrier, Dalmatian, Dobermann pinscher, English cocker spaniel, English springer spaniel, Great Dane, Labrador retriever and Samoyed. The median age at diagnosis for all breeds with CH was 8 years (range 7 months to 16 years). Dalmatians, Dobermann pinschers and English springer spaniels with CH were significantly younger than Cairn terriers, English cocker spaniels and Labrador retrievers with CH. Females were over-represented when all cases were examined together. In conclusion, several breeds in the UK have an increased risk of CH, some of which have not been previously reported.     

Canine keratoconjunctivitis sicca: disease trends in a review of 229 cases

OBJECTIVES: To investigate the disease patterns in dogs with keratoconjunctivitis sicca referred to the University of Glasgow Small Animal Hospital. METHODS: A retrospective study of 229 cases was carried out. RESULTS: There were 44 breeds in the study, with four breeds, English cocker spaniels, cavalier King Charles spaniels, West Highland white terriers and shih-tzus, making up 58 per cent of the cases. Among these four breeds, two breed-dependent disease patterns, one chronic and one acute, were identified. English cocker spaniels and West Highland white terriers had a mean age at onset of clinical signs of five years and one month and five years and six months, respectively, with more females affected than males. Clinical signs consisted predominantly of conjunctival hyperaemia and mucopurulent discharge, with a relatively low incidence of ulcerative keratitis. In contrast, cavalier King Charles spaniels and shih-tzus showed a more acute disease pattern with a biphasic age distribution at 0 to less than two years of age, and four to less than six and six to less than eight years of age, respectively, with more males affected than females and a significantly higher incidence of ulcerative keratitis in some cases resulting in corneal perforation. CLINICAL SIGNIFICANCE: The study reveals interbreed differences with respect to sex, age and risk of ulcerative keratitis which have not been detailed previously in a referral population.     

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).     

The association between the signalment, common causes of canine otitis externa and pathogens

Objective : To determine whether associations exist between pathogens, allergies, conformational abnormalities, endocrinopathies and signalment in canine otitis externa (OE). Methods : Medical records of 149 dogs which met predetermined inclusion criteria were evaluated retrospectively. Correlations between pathogens and the presence of allergy, endocrinopathy, conformational abnormalities and signalment were evaluated statistically. Results : The shar‐pei, German shepherd and cocker spaniel breeds were over‐represented compared with the hospital's breed distribution (P<0·001). German shepherd dogs and cocker spaniels were statistically more prone to infection with rod‐shaped organisms and Labrador retrievers less than other breeds (P=0·034). Almost all dogs that were older than five years when diagnosed with OE had cocci (P=0·01) and also had higher levels of rods (P=0·028). The incidence of rods was higher in endocrinopathies (P=0·004), while that of Malassezia spp. tended to be higher in allergies (P=0·098). There were no statistically significant differences among the groups for all the other parameters examined. Clinical Significance : OE infection is usually not influenced by primary causes or predisposing factors. Endocrinopathies may be followed by a more severe otitis, however. OE may be more severe when it affects older dogs.     

Ventricular tachycardia in English bulldogs with localised right ventricular outflow tract enlargement

Objectives : To describe the electrocardiographic characteristics of ventricular tachycardia arising from the right ventricular outflow tract and the particular association between this arrhythmia and the presence of localised right ventricular outflow tract enlargement in English bulldogs. Methods : Five English bulldogs were referred with a history of syncope or cardiogenic shock. In all dogs, 12‐lead surface ECG, thoracic radiograph and echocardiography were collected. In all but one dog 24‐hours Holter monitoring and signal‐averaged ECGs was examined and in one dog electrophysiological study and radiofrequency catheter ablation of the VT substrate was performed. Results : Documented arrhythmias included a single sustained monomorphic wide QRS tachycardia in four dogs, and an alternans of two different monomorphic forms in one dog. Mean QRS duration during tachy‐cardia was 91·6 ±9·83 milliseconds. QRS complexes manifested a left bundle branch block morphology and an inferior axis (81 ±13·73°). R wave notching was present in the caudal (inferior) leads in three tachy‐cardias. Lead I was negative in 3 of 6, positive in 1 of 6 and isodiphasic in 2 of 6. Lead aVL was negative in 5 of 6 and positive in 1 of 6. Signal‐averaged electrocardiograms revealed late potentials in three dogs. Echocardiography showed a localised right ventricular outflow tract enlargement in all dogs. Cardiac map‐ping established two sites of origin of ventricular tachycardia within the right ventricular outflow tract in one dog: caudal free‐wall and cranial‐septal. Clinical Significance : The presence of a localised right ventricular outflow tract enlargement and ventricular tachycardia with left bundle branch block morphology could suggest segmental arrhythmogenic right ven‐tricular cardiomyopathy in the English bulldog.     

Results of ambulatory electrocardiography in overtly healthy Doberman Pinschers with equivocal echocardiographic evidence of dilated cardiomyopathy

OBJECTIVE: To determine results of ambulatory electrocardiography in and outcome of overtly healthy Doberman Pinschers with equivocal echocardiographic evidence of dilated cardiomyopathy. DESIGN: Case series. ANIMALS: 44 overtly healthy (25 male, 19 female) Doberman Pinschers. PROCEDURE: 24-hour ambulatory electrocardiographic (Holter) recordings with > 90% scan quality obtained the same day that echocardiography was performed were reviewed. RESULTS: Holter recordings from 42 of 44 (95%) dogs contained ventricular premature complexes (VPC). Fifteen of 44 (34%) dogs had > 100 VPC, 9 (20%) had > 500 VPC, and 5 (11%) had > 1,000 VPC. Nonsustained (< 30 seconds) ventricular tachycardia was detected in 4 dogs. Eighteen of 27 (67%) dogs with > 100 VPC, any couplets or triplets of VPC, or ventricular tachycardia developed dilated cardiomyopathy within 1 year, compared with 8 of 17 (47%) dogs with < 100 VPC, no couplets or triplets of VPC, and no ventricular tachycardia. Of the 18 dogs that did not develop dilated cardiomyopathy within 1 year, 11 (61%) did so within 3 years. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a high percentage of Doberman Pinschers with equivocal echocardiographic evidence of dilated cardiomyopathy will be found to have VPC during 24-hour ambulatory electrocardiography and that most will develop echocardiographic abnormalities indicative of cardiomyopathy.     

Effects of preemptive atropine administration on incidence of medetomidine-induced bradycardia in dogs

OBJECTIVE: To determine the cardiorespiratory effects of preemptive atropine administration in dogs sedated with medetomidine. DESIGN: Randomized crossover trial. ANIMALS: 12 healthy adult dogs. PROCEDURES: Dogs underwent 6 treatments. Each treatment consisted of administration of atropine (0.04 mg/kg [0.018 mg/lb] of body weight, IM) or saline solution (0.9% NaCl, 1 ml, IM) and administration of medetomidine (10, 20, or 40 microg/kg [4.5, 9.1, or 18.2 microg/lb], IM) 10 minutes later. Treatments were administered in random order, with a minimum of 1 week between treatments. Cardiorespiratory effects before and after atropine and medetomidine administration were assessed. Duration of lateral recumbency and quality of sedation and recovery were assessed. RESULTS: Bradycardia (heart rate < 60 beats/min) was seen in all dogs when saline solution was administered followed by medetomidine, and the dose of medetomidine was not associated with severity or frequency of bradycardia or second-degree heart block. However, a medetomidine dose-dependent increase in mean and diastolic blood pressures was observed, regardless of whether dogs received saline solution or atropine. Preemptive atropine administration effectively prevented bradycardia and second-degree heart block but induced pulsus alternans and hypertension. The protective effects of atropine against bradycardia lasted 50 minutes. Blood gas values were within reference limits during all treatments and were not significantly different from baseline values. Higher doses of medetomidine resulted in a longer duration of lateral recumbency. CONCLUSIONS AND CLINICAL RELEVANCE: Preemptive administration of atropine in dogs sedated with medetomidine effectively prevents bradycardia for 50 minutes but induces hypertension and pulsus alternans.     

Clinical utility of serum N-terminal pro-B-type natriuretic peptide concentration for identifying cardiac disease in dogs and assessing disease severity

OBJECTIVE: To determine whether serum N-terminal pro-B-type natriuretic (NT-proBNP) concentration could be used to identify cardiac disease in dogs and to assess disease severity in affected dogs. DESIGN: Cross-sectional study. ANIMALS:119 dogs with mitral valve disease, 18 dogs with dilated cardiomyopathy, and 40 healthy control dogs. PROCEDURES: Serum NT-proBNP concentration was measured with an ELISA validated for use in dogs. Results of physical examination, thoracic radiography, echocardiography, and serum biochemical analyses were recorded for dogs with cardiac disease. RESULTS:Serum NT-proBNP concentration was significantly higher in dogs with cardiac disease than in control dogs, and a serum NT-proBNP concentration > 445 pmol/L could be used to discriminate dogs with cardiac disease from control dogs with a sensitivity of 83.2% and specificity of 90.0%. In dogs with cardiac disease, serum NT-proBNP concentration was correlated with heart rate, respiratory rate, echocardiographic heart size, and renal function. For dogs with cardiac disease, serum NT-proBNP concentration could be used to discriminate dogs with and without radiographic evidence of cardiomegaly and dogs with and without congestive heart failure. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that serum NT-proBNP concentration may be a useful adjunct clinical test for diagnosing cardiac disease in dogs and assessing the severity of disease in dogs with cardiac disease.     

Hereditary phosphofructokinase deficiency in wachtelhunds

Hereditary phosphofructokinase (PFK) deficiency was diagnosed in two Wachtelhund dogs and suspected in three related Wachtelhund dogs with exercise intolerance, hemolytic anemia, and pigmenturia. Severe, persistent reticulocytosis in light of only mild anemia together with hemoglobinuria after strenuous exercise suggested PFK deficiency. Low erythrocyte PFK activity together with low 2,3-diphosphoglycerate concentrations and a high hemoglobin-oxygen affinity confirmed the diagnosis. The PFK deficiency is due to a single missense mutation in the muscle-type PFK M-PFK gene in English springer and American cocker spaniels, whippets, and mixed-breed dogs; however, these PFK-deficient Wachtelhunds do not have the same PFK mutation.     

Breed, sex and age distribution in dogs with chronic liver disease: a demographic study

Breed, sex and age distribution were studied in dogs with histopathologically diagnosed chronic (active or progressive) hepatitis and liver cirrhosis in Sweden. The study was based on clinical and histopathological records obtained during three years from a histopathological laboratory and during six years from an animal hospital. Some breeds were significantly (P<0–001) over-represented: American and English cocker spaniels, labrador retrievers and West Highland white terriers. In both spaniel breeds the males were most frequent whereas in the labrador retriever, the females were over represented. In the West Highland white terrier there was no sex difference. The average age at presentation was approximately five years in spaniels and West Highland white terriers and seven years in labrador retrievers. The high incidence of chronic liver disease and liver cirrhosis in certain breeds indicate that hereditary factors may be of importance in the development of chronic hepatitis and liver cirrhosis.     

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.     

Taurine-deficient dilated cardiomyopathy in a family of golden retrievers

A reversible taurine-deficient dilated cardiomyopathy occurred in five related golden retrievers. An apical systolic heart murmur was the most common physical abnormality. According to fractional shortening and end-systolic diameter on echocardiography, significant improvements (P<0.005) were recorded within 3 to 6 months of starting taurine supplementation. The dogs regained substantial systolic function, and four were weaned off all cardiac medications except taurine. This response to therapy was unusual, because canine dilated cardiomyopathy is generally progressive and fatal.