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1.
The trabecula septomarginalis dextra is a structure routinely mentioned in veterinary anatomy. While there are several studies on the morphology of this structure in select animal species, there are some characteristics that are not adequately described. The purpose of this study was to describe and classify this trabecula in the domestic dog using the number of branches that insert onto the ventricular free wall. In the 39 examined hearts, 17.95% were single stranded (type I) and 2.56% were y‐shaped (IA). Then, 28.21% were web‐like with 3 to 4 points of insertion (IB) and 51.28% were web‐like with 5 or more points of insertion (IC). While the purpose of this study was to describe the morphology of this trabecula, it also showed there is variability in this structure within the same species. This undocumented variability could present a problem to researchers who use dogs as an animal model when testing catheters for invasive cardiac monitoring or cardiac stem cell therapy. Also a web‐like trabecula could create problems during pacemaker lead placement for the treatment of symptomatic bradycardia because of the potential for catheter entanglement in these branches.  相似文献   

2.
Ventricular bands, also designated as ‘false tendons’, are described as single or multiple strands that cross the ventricles and have no connection to valvular cusps. Previous work indicates these strands are present in the ventricles of humans and some animal hearts and not always associated with cardiac pathologies. Despite these previous studies, the published literature is limited in documenting the morphology of these strands and incidence in animals. In this study, examination of 89 hearts showed six types of ventricular bands in the right ventricle of the domestic dog. These bands were classified according to their prevalence and points of attachment. Type I extended from the interventricular septum to the ventricular free wall, type II connected a musculus papillaris parvus to the ventricular free wall and type III connected trabeculae carneae on the interventricular septum. Type IV connected the trabeculae carneae on the ventricular free wall, type V interconnected papillary muscles and type VI connected the interventricular septum to a papillary muscle. While the study of these ventricular bands provided additional information on the cardiac anatomy of the domestic dog, it also showed their clinical importance. Several studies have proposed that their position in the ventricle may interfere with cardiac catheterization and pacemaker lead placement or be misinterpreted during echocardiography.  相似文献   

3.
The morphology of moderator bands in both heart ventricular cavities was examined on macro‐ and microscopic levels in 14 six‐month‐old Landrace pigs. One transverse moderator band, measuring 2.9 ± 0.6 mm in diameter, was located between the septum and the free wall of the right ventricular cavity. On cross‐section, clumps of conductive cells were found at the periphery of the moderator band and in its central part around the blood vessels. Large amounts of muscle fibres were identified. The left ventricular cavity contained moderator bands in the form of thin cords, measuring 1.05 ± 0.09 mm in diameter and located mostly between the interventricular septum and the papillary muscles. Conductive tissue was represented by clumps of Purkinje cells, surrounded by myocardial fibres. The proportion of conductive cells and muscle fibres in the moderator bands was approximately the same. Owing to different amounts of conductive cells and muscle fibres in the bands, we assume that moderator bands in the right and left ventricles play different primary functional roles. Our results were compared with previous data on pigs and other ungulate animal species.  相似文献   

4.
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5.
A 7-year-old female boxer dog died suddenly without any clinical signs. It was suspected that the dog had arrhythmogenic right ventricular cardiomyopathy (ARVC) due to ventricular premature complexes and ventricular tachycardia at 3 years of age. The final diagnosis of ARVC was confirmed by histological characteristics, such as loss of cardiocytes and fibrofatty replacement, occurring in the right and left ventricular walls. In the cardiocytes, non-lipid vacuoles were observed. Cardiac fibrosis and intimal thickening of the small arteries occurred without fatty replacement in the inner muscle layer including the papillary muscles of the left ventricular wall. This paper describes the pathomorphological details of an ARVC case with coincidental cardiac fibrosis in the inner muscle layer of the left ventricular wall.  相似文献   

6.
The hearts of four dogs (a 4-year-old Shetland sheepdog, a 4-year-old Labrador retriever, a 5-year-old English Bulldog, and a 6-year-old Dalmatian; three males and one female), that had died suddenly and had been clinically diagnosed as having arrhythmogenic right ventricular cardiomyopathy (ARVC), were studied post mortem. At the cut surface, all four hearts showed mild to moderate hypertrophy of the left and right ventricular free walls and ventricular septum, with grayish-white tissue replacement of the myocardium to various degrees. Histologically, all had typical right ventricular features of ARVC and morphological evidence of left ventricular and ventricular septal involvement. Two main histological patterns were identified: a fatty type (two cases) and a fibrofatty type (two cases). With either type, myocardial replacement by fatty or fibrofatty tissue were detected in both ventricles, but were more severe in the right ventricle, where they usually became transmural. Furthermore, this myocardial replacement was more severely seen in the epimyocardium and midmyocardium; the endomyocardium was less severely affected. On the basis of the present observation, it is evident that, in dogs, the disease process of ARVC affects both the right and left ventricles, although the striking pathological feature is right ventricular involvement. The pathological evidence of biventricular involvement in these canine cases of ARVC may represent a wider spectrum of the disease than has previously been recognized, suggesting that, in dogs, this disease should no longer be considered as limited to the right ventricle.  相似文献   

7.
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.  相似文献   

8.
Dysplasia of the tricuspid valve in 14 dogs and 13 cats was studied. The clinical, electrocardiographic, radiographic, hemodynamic, angiocardiographic, and pathologic findings were reviewed in each species. Alterations of the tricuspid valve complex included long, thick septal leaflets adhered to the septum; absent or short, stout fused chordae tendineae; hypertrophic fused papillary muscles; insertion of papillary muscles directly into the lateral leaflets; incomplete development of the valvular tissue; and enlargement of the right atrium and ventricle. Additional intracardiac anomalies included malformation of the mitral valve complex (5 dogs and 3 cats), ventricular septal defect (3 dogs and 3 cats), pulmonary stenosis (1 dog and 1 cat), aortic stenosis (1 dog and 1 cat), and persistent left cranial vena cava (1 dog).  相似文献   

9.
The right ventricle was studied in 75 anatomically normal swine hearts, using, in all, nine geometric and volumetric parameters: ventricular-wall thickness, length of the right-ventricular inflow and outflow tracts, and volume of the right-ventricular inflow and outflow tracts. The data for these parameters were compared with previously published patterns for human hearts and volumetric data were compared with patterns of normality found in human hearts. As in the human heart, the ventricular inflow tract in swine hearts was significantly shorter than the outflow tract (P < 0.0001).  相似文献   

10.
Radiographically, the size of the right ventricle of 54 heartworm-infected dogs was graded subjectively as normal, 1 +, 2 +, and 3 + and served to classify the dogs into groups A, B, C, and D. With M-mode echocardiograms, right ventricular enlargement ratios (RVE ratios) were determined for each dog by dividing the measured right ventricular internal diastolic dimension (RVIDd) by the expected RVIDd of a normal dog of the same body weight. The normal RVIDd relation to body weight was derived from 25 healthy heartworm-free control dogs. These two variables were linearly related with a correlation coefficient r2= 0.59. Means and standard deviations of the RVE ratio were calculated for each group. Despite wide ranges and considerable overlap, the ratio was significantly different (t-test, p < 0.005) between groups with the exception of groups A and B, and C and D. The incidence of electrocardiographic signs of right ventricular hypertrophy was also determined for each group; it was 38% in group C and 62% in group D. From this data, it was concluded that M-mode echocardiography is a very sensitive technique for the documentation of right ventricular dilatation in heartworm-infected dogs, correlating with radiographic impressions of right ventricular enlargement.  相似文献   

11.
The incidence, distribution, and macro‐ and microscopic structures of left ventricular false tendons (LVFTs) in the cat heart were studied using 25 normal and 57 diseased hearts. The fibrous bands were observed in the left ventricle of all 82 cat hearts examined and most commonly extended between the papillary muscles and the ventricular septum. Histologically, the LVFTs were composed of central Purkinje fibres and surrounding dense collagenous fibres covered by endothelium. There was no appreciable difference in the incidence, distribution or morphology of LVFTs between the normal and the diseased hearts, indicating that LVFTs are a common anatomic variant in the cat heart.  相似文献   

12.
A 32-month-old spayed female Pug was referred for an MRI study due to convulsions. The MRI examination indicated encephalitis. However, echocardiography and pathological examinations revealed that this case had a ventricular septal defect and double chambered right ventricle which is a rare congenital heart disease in the dog. An anomalous muscle bundle crossed the right ventricular outflow tract, dividing the right ventricle into 2 chambers.  相似文献   

13.
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14.
A seven-month-old male Siberian husky was presented with a recent history of anorexia, hindlimb weakness and syncope. Physical examination revealed severe tachycardia, tachypnoea and dyspnoea. Mucous membranes were pale and femoral pulses were weak. An electrocardiogram showed sustained ventricular tachycardia with a left bundle branch block configuration. Thoracic radiographs revealed slight right ventricular enlargement and two-dimensional echocardiography revealed mild right ventricular dilation at the cardiac apex and some hyperechogenic areas on the right side of the interventricular septum. Administration of intravenous lignocaine converted the ventricular tachycardia to sinus rhythm. The maintenance antiarrhythmic therapy consisted of oral procainamide and propranolol. Three weeks later the dog died suddenly. On postmortem examination, the right ventricular free wall was very thin at the apex, infundibulum and caudal aspect of the right ventricular parietal wall, similar to the 'triangle of dysplasia' of human patients. Histopathological examination revealed replacement of several areas of right ventricular free wall myocardium with connective tissue and fat. The right atrium and left ventricle were less severely affected by the same lesions. The clinical and pathological findings are similar to those reported in young people with arrhythmogenic right ventricular dysplasia/cardiomyopathy.  相似文献   

15.
Growth, gravidity and lactation put high demands on the performance of the myocardium. The aim of this study, which was performed in 40 female and 20 male bovines ranging from 1 to 4.5 years old, was to determine gross and microscopic morphometric data of bovine myocardium to establish a comparative measure of myocardial growth during juvenile development. During the developmental stage of young adulthood, age‐related increases in female myocardial characteristics included cardiac mass, left and right ventricular mass and the ratio of cardiac mass to loose connective tissue. Age‐related decreases were observed in the number of myocyte nuclei per mm² and the thickness of the right ventricular wall. Sex differences in these parameters were found between 2‐year‐old bulls (N = 20) and 2‐year‐old heifers (N = 10), with males having heavier hearts, thicker ventricular walls, less myocytes in the left ventricle and less connective tissue in both ventricles. Age and sex had no influence on the ratio of capillaries to myocytes, estimated at 0.98 in the adult bovine. Capillary density does not change during juvenile development, but cross‐sectional capillary area does adapt to myocyte cross‐sectional area, accounting for this relatively constant ratio.  相似文献   

16.
Five dogs and 1 cat had pulmonary artery banding for ventricular septal defect and congestive heart failure. An umbilical tape band constricted the pulmonary artery to one-third its original diameter, increased the right ventricular pressure, and decreased the left ot right shunt. Five animals had remission of clinical signs; 1 dog died of right ventricular failure due to a band that had been applied too tightly. The results indicated pulmonary artery banding is helpful in reduction of clinical signs, due to increased flow to the lungs from ventricular septal defect.  相似文献   

17.
Ventricular dyssynchrony is a disturbance of the normal, organized electromechanical coupling of the two ventricles. This condition has many causes, such as left bundle branch block, ventricular preexcitation, right ventricular pacing and right ventricular premature ventricular complexes (PVCs). Ventricular dyssynchrony has many adverse haemodynamic effects on the left ventricle and we wanted to know whether these adverse haemodynamic effects might have any structural consequences on the left ventricles of such hearts. Six healthy Dorper wethers were subjected to numerous right ventricular PVCs to induce ventricular dyssynchrony in order to determine whether any structural consequences will occur in the left ventricles of these hearts. Myocarditis in the musculature of the left ventricles of all six these hearts was seen.  相似文献   

18.
The size of the right ventricle of 15 dogs with spontaneous Dirofilaris immitis microfilaria was evaluated by thoracic radiography, electrocardiography, and right ventricular free wall weights. Based on electrocardiography and right ventricular weights, none of the 15 dogs had evidence of right ventricular hypertrophy. Based on radiography, only 2 of the 15 dogs had right ventricles of normal size. Right ventricular dilation in the absence of right ventricular hypertrophy was demonstrated. The right ventricle appears to dilate, prior to hypertrophy, in response to D immitis infestation.  相似文献   

19.
A 6-year-old, neutered male Labrador Retriever was diagnosed with congestive heart failure, and an echocardiogram revealed a large mass inside the pericardial sac associated with the left ventricle. At necropsy, the dog had marked ascites, mild hydrothorax, marked hydropericardium, and an 11.0 x 7.0 x 6.0 cm, tan and red, firm, well-demarcated mass attached to the left ventricular free wall. The mass was diagnosed as a fibrosarcoma based on the morphologic appearance and supportive immunohistochemical staining. To our knowledge, this is the first case report of a primary fibrosarcoma involving the left ventricular free wall myocardium, epicardium, and pericardium with a pulmonary metastasis in a dog.  相似文献   

20.
A beagle dog treated with saline as a control animal in a preclinical study was euthanized due to sudden systemic deterioration. On histopathological examination, contraction band necrosis of myocardial cells was observed widely in the left ventricular wall, including the papillary muscle and apex, and observed slightly in the ventricular septum and left atrium. In the brain, necrosis was observed in neurons and glia of the cerebral cortex, hippocampal pyramidal cells, glial cells of the rostral commissure and Purkinje cells of the cerebellar vermis. It is highly probable that the marked systemic deterioration was caused by cardiac dysfunction due to the spontaneous contraction band necrosis of the myocardial cells, although the pathogenesis of the myocardial lesions remains unclear. Given the distribution of neuronal necrosis in the brain, it is likely that these lesions resulted from the ischemia responsible for acute cardiac failure.  相似文献   

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