Malformation of the canine mitral valve complex.

Twenty-nine dogs, including 13 Great Danes and 5 German Shepherd Dogs and averaging 7.3 months age, were diagnosed clinically and radiographically as having mitral regurgitation. Alterations of the mitral valve complex included enlarged anulus; short thick leaflets, with an occasional cleft; short and stout or long and thin chordae tendineae; upward malposition of atrophic or hypertrophic papillary muscles; insertion of one papillary muscle directly into one or both leaflets; and diffuse endocardial fibrosis, occasionally with jet lesions in te left atrium. Other cardiac anomalies included dysplasia of the tricuspid valve (5 dogs), patent ductus afteriosus (2 dogs), aortic stenosis (2 dogs), and ventricular septal defect (1 dog).     

Surgical Palliation of Severe Tricuspid Valve Stenosis in a Dog by Use of Fontan's Procedure

OBJECTIVE: To describe surgical treatment of tricuspid valve stenosis using the Fontan procedure in a young dog. STUDY DESIGN: Case report. SAMPLE POPULATION: One client-owned dog RESULTS: A six month old female Labrador retriever was diagnosed with tricuspid obstruction. The dog had a displaced tricuspid valve and small right ventricle and had progressed to right-sided (backward) cardiac failure. A Fontan procedure (connection of the right atrium to the pulmonary artery with a prosthetic conduit) was performed. Within three days the right atrial pressure had dropped from a preoperative value of 33 mm Hg to 8 mm Hg and the ascites was significantly reduced. The dog died suddenly two months after surgery. Postmortem examination of the heart showed a greatly enlarged right atrium and hypoplastic right ventricle. The tricuspid valve leaflets were fused and displaced ventrally leaving an opening measuring 3x5 mm between the chambers. The conduit was intact with no evidence of leakage or thrombosis. CONCLUSIONS: Palliation of tricuspid stenosis using the Fontan procedure can be performed in dogs. Sudden death may occur and is most likely because of cardiac arrythmias.     

Review of thymic pathology in 30 cats and 36 dogs

Data are presented from 30 cats and 36 dogs in which thymic disease was recognised clinically or on postmortem examination. The diagnoses included thymic lymphoma (19 cats, l 2 dogs), thymoma (five cats, 18 dogs), thymic branchial cyst formation or cystic change (one cat, four dogs), thymic hyperplasia (two cats), congenital hypoplasia (one cat, one dog), thymic haemorrhage (one cat, one dog) and thymic amyloidosis (one cat). Thymic lymphoma occurred in younger dogs and cats, and was recorded equally among domestic shorthaired and purebred (especially Siamese) cats. Eight cats with thymic lymphoma were tested for feline leukaemia virus and four were positive. Thymoma occurred more frequently in older cats and dogs, and in Labradors and German shepherd dogs. Thymic tumours were associated with paraneoplastic hypercalcaemia (six dogs), megaoesophagus (two dogs) or interface dermatitis with basement membrane immune complex deposition (one cat). Non-neoplastic thymic diseases were associated with myasthenia gravis (one cat), pemphigus foliaceus (one cat) and superficial necrolytic dermatitis (one cat).     

Mitral Stenosis in 15 Dogs

Mitral stenosis was diagnosed in 15 young to middle-aged dogs. There were 5 Newfoundlands and 4 bull terriers affected, suggesting a breed predisposition for this disorder. Clinical signs included cough, dyspnea, exercise intolerance, and syncope. Soft left apical diastolic murmurs were heard only in 4 dogs, whereas 8 dogs had systolic murmurs characteristic of mitral regurgitation. Left atrial enlargement was the most prominent radiographic feature. Left-sided congestive heart failure was detected by radiographs in 11 dogs within 1 year of diagnosis. Electrocardiographic abnormalities varied among dogs and included atrial and ventricular enlargement, as well as atrial and ventricular arrhythmias. Abnormalities on M-mode and two-dimensional echocardiograms included abnormal diastolic motion of the mitral valve characterized by decreased leaflet separation, valve doming, concordant motion of the parietal mitral valve leaflet, and a decreased E-to-F slope. Increased mitral valve inflow velocities and prolonged pressure half-times were detected by Doppler echocardiography. Cardiac catheterization, performed in 8 dogs, documented a diastolic pressure gradient between the left atrial, pulmonary capillary wedge, or pulmonary artery diastolic pressures and the left ventricular diastolic pressure. Necropsy showed mitral stenosis caused by thickened, fused mitral valve leaflets in 5 dogs and a supramitral ring in another dog. The outcome in affected dogs was poor; 9 of 15 dogs were euthanatized or died by 2 1/2 years of age.     

Balloon valvuloplasty for palliative treatment of tricuspid stenosis with right-to-left atrial-level shunting in a dog

A 3.75-year-old castrated male Chesapeake Bay Retriever was referred for evaluation of tachypnea, exercise intolerance, and cyanosis. Echocardiographically, there was severe tricuspid stenosis and right-to-left atrial-level shunting of blood. Marked compensatory polycythemia had developed; the PCV was 75%. Balloon dilation of the tricuspid stenosis was performed. Subsequent echocardiographic examinations demonstrated a reduction in the pressure gradient across the tricuspid valve. The PCV returned to the reference range, and the dog's clinical status improved during the 12 months after the procedure. Tricuspid stenosis is an uncommon lesion in dogs and, in the dog of this report, was assumed to have resulted from tricuspid dysplasia. Cyanosis was a result of right-to-left shunting of blood. Limited treatment is available for dogs with cyanotic heart disease. In this dog, balloon dilation of the stenotic tricuspid valve was palliative.     

Epidemiological and morphological studies of double-chambered right ventricle in dogs

The double-chambered right ventricle (DCRV) is a rare congenital cardiac disease in dogs, and its detailed epidemiological and morphological features are not clearly understood. By investigating the profile, clinical signs, and characteristics of examination findings of eleven dogs with DCRV by means of a retrospective study, we attempted to clarify the epidemiology and morphology of the condition. The study group consisted of nine males and two females. Breeds included Pug (n=3), Miniature Dachshund (n=1), French Bull-dog (n=1), Shiba (n=1), and Retrievers (n=5). The attachment site of the anomalous muscular bundle was continuous with the cardiac apex in nine dogs, and it was attached to the right ventricle free wall in the other two dogs. In dogs with DCRV, at least one of the following conditions was present concurrently: congenital or acquired tricuspid valve regurgitation (TR), ventricular septal defect, and atrial septal defect. Also, the pressure difference between the two chambers increased over time, and progressive right-sided heart failure was observed. In summary, DCRV occurs in small breeds of dog as well as in large breeds of dog and it may be more prevalent in males. The existence of two types of DCRV in dogs was established. Dog with DCRVs will have a high incidence of concurrent cardiac abnormalities. Concurrent TR may be either congenital or acquired. DCRV is a congenital disorder, but the clinical condition progresses as the dog develops.     

Mitral valve stenosis in three cats

Two-dimensional and M-mode echocardiography were used to diagnose mitral stenosis in two cats with heart failure. This appeared to be related to mitral valve complex malformation. Ultrasound findings included thickened mitral valve leaflets with inhibited mobility, reduced mitral valve orifice size, abnormal upward (cranial) motion of the caudal mitral leaflet during diastole and severe left atrial enlargement. Colour-flow and spectral Doppler imaging helped characterise this condition. Colour-flow Doppler mapping showed turbulence and increased mitral filling velocity (aliasing) at the site of stenosis and related jets of mitral regurgitation. Spectral Doppler recordings showed increased diastolic mitral filling velocities with spectral broadening and prolonged pressure half-time. Mitral stenosis should be included in the differential diagnosis of cats with severe left atrial enlargement when congenital or acquired mitral valve disease is detected; it may represent an advanced form of mitral valve complex malformation in some cases.     

Stenting of the right ventricular outflow tract in 2 dogs for palliation of dysplastic pulmonary valve stenosis and right-to-left intracardiac shunting defects

Two dogs with severe dysplastic pulmonary valve stenosis and right-to-left shunting defects (patent foramen ovale, perimembranous ventricular septal defect) underwent palliative stenting of the right ventricular outflow tract and pulmonary valve annulus using balloon expandable stents. One dog received 2 over-lapping bare metal stents placed 7 months apart; the other received a single covered stent. Both procedures were considered technically successful with a reduction in the transpulmonary valve pressure gradient from 202 to 90 mmHg in 1 dog and from 168 to 95 mmHg in the other. Clinical signs of exercise intolerance and syncope were temporarily resolved in both dogs. However, progressive right ventricular concentric hypertrophy, recurrent stenosis, and erythrocytosis were observed over the subsequent 6 months leading to poor long-term outcomes. Stenting of the right ventricular outflow tract is feasible in dogs with severe dysplastic pulmonary valve stenosis, though further study and optimization of the procedure is required.     

Trifoliate left atrioventricular valve with and without intact septal structures in four dogs: echocardiographic findings and surgical repair

Trifoliate left atrioventricular (AV) valve with common atrioventricular junction is considered part of the spectrum of atrioventricular septal defect. This valve morphology is typically associated with defects in the AV septum resulting in communication at the atrial or ventricular level, but has also been described as an isolated defect in the setting of a common AV junction without AV septal defect. Trifoliate left AV valve exhibits a line of apposition between the bridging leaflets that is directed toward the inlet interventricular septum, distinguishing it from isolated mitral valve cleft in which the orientation of the bridging leaflets are toward the left ventricular outflow tract. The echocardiographic findings of four dogs with trifoliate left AV valve are described; two with intact septal structures and two with large ostium primum defects. Three dogs underwent open surgical repair using different approaches depending on the presence or absence of a septal defect. One of these underwent concurrent surgical repair for right AV valve dysplasia. One dog with intact septal structures underwent interventional closure of a concurrent patent ductus arteriosus. Current terminology associated with trileaflet left AV valve malformations is reviewed.     

Sporotrichosis: a retrospective evaluation of 23 cases seen in northern California (1987–2007)

Sporotrichosis is an uncommon to rare cutaneous and subcutaneous mycosis of animals and humans caused by the dimorphic fungus Sporothrix schenckii . Twenty-three mammalian cases of sporotrichosis examined between 1987 and 2007 at the University of California, Davis – Veterinary Medical Teaching Hospital, were retrospectively evaluated with regard to the historical, clinical, diagnostic and treatment findings. Cats were the most common species affected ( n  = 14). In addition, sporotrichosis was diagnosed in four dogs, four horses and a donkey. Six of 23 cases were diagnosed with the localized cutaneous form of sporotrichosis (four cats, one dog, one horse), 10 with the cutaneous-lymphatic form (four cats, two dogs, three horses and a donkey), and seven with the disseminated form (six cats, one dog). Two of 23 cases did not have skin lesions at the time of diagnosis (one cat, one dog). The most common mode of diagnosis was demonstration of S. schenckii on histopathological evaluation of tissue. In contrast with most previously described sporotrichosis infections in cats, few to no fungal organisms were seen in histopathological samples (haematoxylin and eosin and special stains) in five of the 14 cats. Treatments received included itraconazole (12 cats, one dog), ketoconazole (three dogs), fluconazole (one cat, one donkey), sodium iodide (four horses, one cat) and potassium iodide (one cat, one horse, one donkey). The prognosis for successful treatment was good in all species. Fluconazole was successful in inducing resolution of the cutaneous lesions and controlling the infection in one cat with disseminated sporotrichosis.     

En Bloc Ovariohysterectomy as a Treatment for Dystocia in Dogs and Cats

En bloc ovariohysterectomy, a technique that involves ovariohysterectomy before hysterotomy and removal of the neonates, was performed on 63 animals (37 dogs and 26 cats). Intraoperative complications were limited to 1 cat that bled excessively during surgery and was later found to have a clotting disorder. Postoperative complications included anemia that required blood transfusion in 3 cats, uroperitoneum in 1 dog, and death in 1 cat. The rate of neonatal survival (75% for dogs and 42% for cats) was similar to that documented by previous studies of medical and surgical management of dystocia. We concluded that en bloc ovariohysterectomy is a safe and effective alternative to cesarean section for surgical treatment of dystocia in dogs and cats.     

Tricuspid valve stenosis caused by fibrous adhesions to an endocardial pacemaker lead in a dog

Acquired tricuspid valve stenosis (TVS) is a rare complication of endocardial lead placement in humans that has not been described in the veterinary literature. We describe a 6.5-year-old Border terrier that was presented with right-sided congestive heart failure 5.5 years after placement of a transvenous pacemaker. Severe TVS was confirmed by cardiac ultrasonography and appeared to be secondary to excessive endocardial pacemaker lead within the right atrium. Repositioning of the lead proved impossible and subsequent postmortem examination demonstrated fusion of the tricuspid valve (TV) leaflets around the endocardial lead with associated narrowing of the tricuspid valve orifice. In addition, the loop of the endocardial lead was anchored by thick fibrous tissue to the right atrial wall. This case report suggests that if sufficient endocardial lead is left inside the heart, in dogs undergoing transvenous pacemaker therapy, the redundant lead can become adherent to the tricuspid valve apparatus and cause valvular stenosis.     

Surgical repair of a complete endocardial cushion defect in a dog

Objective: To describe surgical repair of a complete endocardial cushion defect (ECD) in a dog. Study Design: Clinical report. Animal: A 5‐month‐old, 9.2 kg male Shetland sheepdog. Methods: Echocardiographic examination revealed an ostium primum atrial septal defect (ASD), an inlet ventricular septal defect (VSD), mitral regurgitation (MR) and tricuspid regurgitation (TR), and a complete ECD was diagnosed. Surgical correction was performed using cardiopulmonary bypass (CPB) via right atriotomy. A polytetrafluoroethylene (PTFE) patch was secured along the margin of the inlet VSD using simple continuous suture, then the cleft in the septal mitral leaflet was sutured. Similarly, the cleft in the septal tricuspid leaflets was sutured. To complete inlet VSD closure, the VSD patch was secured to these sutured leaflets by simple continuous suture. Another PTFE patch was used to close the ostium primum ASD. Result: After surgery, MR, TR, and interventricular shunting were decreased. The dog was alive 6 years and 5 months after the surgery with no evidence of an interventricular shunt, TR, or other clinical signs. Conclusions: Complete ECD in a dog was corrected using a 2‐patch technique under CPB.     

Outcome in 55 dogs with pulmonic stenosis that did not undergo balloon valvuloplasty or surgery

Objective : To determine the outcome, independent predictors of cardiac death, and the Doppler‐derived pressure gradient cut‐off for predicting cardiac death in dogs with pulmonic stenosis, with or without tricuspid regurgitation, that do not undergo balloon valvuloplasty or valve surgery. Methods : Review of medical records of two UK referral centres between July 1997 and October 2008 for all cases of pulmonic stenosis that had no balloon valvuloplasty or valve surgery. Inclusion criteria included a diagnosis of pulmonic stenosis; spectral Doppler pulmonic velocity greater than 1·6 m/s; characteristic valve leaflet morphological abnormalities. Exclusion criteria included concurrent significant cardiac defects, including tricuspid dysplasia. Dogs with tricuspid regurgitation were included. Dogs were classified according to Doppler‐derived pressure gradients into mild, moderate or severe pulmonic stenosis categories. Results : Presence of tricuspid regurgitation and severe stenosis were independent predictors of cardiac death. A pulmonic pressure gradient of more than 60 mmHg was associated with 86% sensitivity, and 71% specificity of predicting cardiac death. Clinical Significance : There is an increased probability of cardiac death in those cases which have a pulmonary pressure gradient greater than 60 mmHg and tricuspid regurgitation, though the effect of severity of tricuspid regurgitation on outcome was not measurable because of small sample sizes. These animals might benefit from intervention.     

Vegetative endocarditis in six cats

Between 1990 and 1997 vegetative endocarditis was diagnosed in six neutered cats (three males, three females) aged between 3 and 9 years. Two cats were purebred (one Persian and one Tonkinese), the remaining four being domestic short haired cats. The diagnosis was made using echocardiography (five cases) or at necropsy (one case). Concurrent involvement of the aortic and mitral valve was noted in four cats, the aortic valve alone was affected in one case, and the tricuspid valve in another. A likely microbiological diagnosis was obtained in three cats: a Bartonella species in two cats based on positive blood culture and a Streptococcus species in one cat based on Gram stain of valve lesions at necropsy. In another cat, Gram-positive cocci were demonstrated histologically in tricuspid vegetations. Invariably, cats had signs of congestive heart failure (left-sided in five cats, right-sided in one), and this was the major factor contributing to mortality in four cases. Signs referable to sepsis were prominent in only two patients. Appropriate medical therapy, consisting of antimicrobials and drugs to treat congestive heart failure, resulted in survival for 5 and 11 months, respectively, in two cases. The other cats died within 2 weeks of diagnosis, including two which received aggressive treatment in hospital.     

New perspectives about Hemotrophic mycoplasma (formerly, Haemobartonella and Eperythrozoon species) infections in dogs and cats.

The new perspectives about hemotrophic mycoplasma infections in cats and dogs can be summarized as follows: Haemobartonella and Eperythrozoon species infecting the dog and cat have been reclassified as mycoplasmal parasites and given the names M haemofelis (Ohio or large form of H felis), M haemominutum (California or small form of H felis), and M haemocanis (H canis). The prevalence of hemotrophic mycoplasma infections in anemic cats in the United States is about 25% and usually involves M haemofelis. However, nonanemic cats may also be infected most commonly with M haemominutum. Chronic infections with hemotrophic mycoplasmas may promote myeloproliferative disorders in FeLV-infected cats. M haemocanis infection in dogs may be a widespread latent disease in kennel-raised dogs and is being investigated. The PCR assay is exquisitely sensitive for detection of M haemofelis and M haemominutum, and testing of blood donor cats and perhaps dogs should be done regularly. Fleas are involved in the transmission of M haemofelis to the cat, whereas R sanguines may be involved with transmission of M haemocanis to the dog. Treatment with doxycycline effectively controls acute infection in the cat and dog, and enrofloxacin may also be effective in the cat, but none of the antibiotics tested to date consistently clears the parasites.     

Papillary muscle measurements in cats with normal echocardiograms and cats with concentric left ventricular hypertrophy

BACKGROUND: Papillary muscle hypertrophy can occur in conjunction with, or as the only indication of, hypertrophic cardiomyopathy or other diseases that result in left ventricular concentric hypertrophy (LVCH). Assessment of papillary muscle size is usually subjective because objective measures have not been reported. HYPOTHESIS: The study hypothesis was that papillary muscle dimensions are different between normal cats and cats with LVCH. ANIMALS: Echocardiograms from 44 normal cats and 40 cats with LVCH were included in the study. METHODS: All measurements were taken from the right parasternal short-axis view at the level of the papillary muscles at end-diastole. Three methods were used to assess papillary muscle size: the area subtraction method, the direct area trace method, and the diameter method. Measurements were compared between cat groups and method comparisons were made among methods for area determination. RESULTS: Cats with LVCH were older and had significantly greater left ventricular septal and free wall thicknesses and larger left atrial measurements than normal cats (P < .0006). Papillary muscle measurements were significantly greater by all measurement methods in cats with LVCH than in cats with normal echocardiograms (P < .0001). The area subtraction method and direct area trace method showed moderate agreement. CONCLUSIONS AND CLINICAL IMPORTANCE: Papillary muscle measurements were larger for LVCH cats than normal cats; however, some overlap was present. The establishment of these objective measures adds to the echocardiographic examination of cats.     

Evaluation of praziquantel for treatment of experimentally induced paragonimiasis in dogs and cats

Praziquantel was used successfully for treatment of a small number of dogs and 1 cat infected with Paragonimus kellicotti. To further evaluate the usefulness of this drug in treating such infections, 7 cats and 7 dogs were inoculated orally with metacercariae (12 and 20 to 22, respectively) obtained from crayfish, then were treated after the infections became patent; 2 cats and 2 dogs served as noninfected controls. Beginning 1 week before infection, and continuing weekly thereafter, physical, hematologic, and fecal examinations were performed on each animal; thoracic radiography was performed every other week. By postinoculation week 6, all dogs given metacercariae had patent infection diagnosed on the basis of positive results of fecal examination. By postinoculation week 7, 5 cats had confirmed patent infection, but 2 cats given metacercariae never had patent infection or had signs of infection. Clinical signs of infection were minor and included increased respiratory tract noise, slight inducible cough, or mild dyspnea. Transient eosinophilia was detected in dogs around postinoculation week 3. Pretreatment radiography revealed cavitated lesions in cats only; pleural lines and patchy infiltrates in cats and dogs; or pneumothorax in dogs only. The treatment regimen consisted of 23 mg of praziquantel/kg of body weight given every 8 hours for 3 days; 1 infected cat and dog were not treated. By 11 days after treatment, eggs had disappeared from the feces of infected animals, and marked resolution of lung lesions was evident radiographically.(ABSTRACT TRUNCATED AT 250 WORDS)