Successful balloon angioplasty of pulmonary artery stenosis in two cats and associated complications.

Two cats (2.5 months and 8 months old) were each evaluated due to a loud systolic murmur, and each was diagnosed with severe pulmonary artery stenosis at the bifurcation of the main pulmonary artery. Echocardiograms confirmed significant right atrial dilation and right ventricular dilation and/or hypertrophy that was progressive in one cat. Atenolol was initiated and the cats were referred for interventional therapy. Balloon angioplasty was performed via the jugular vein. In case 1, the pressure gradient across the stenosis was reduced from 169.7 mmHg to 23.6 mmHg and 52.4 mmHg across the left and right branch pulmonary arteries, respectively. In case 2, the stenotic echocardiographic gradient was reduced from 64 mmHg to 38.0 mmHg and 35.3 mmHg across the left branch and right-branched pulmonary arteries respectively. Both patients developed moderate to severe dynamic right ventricular outflow tract obstruction post angioplasty. Case 2 developed hypotension, desaturation, and ventricular arrhythmias intra-operatively. Case 1 was discharged but appeared to develop acute lung perfusion injury approximately 36 h after procedure that was manifested by radiographic pulmonary congestion and pulmonary infiltrate of the left lung fields. The congestion was successfully managed medically. Serial echocardiograms over the following 4 years in case 1 showed near complete resolution of the stenosis and associated right heart enlargement.

Prevalence of congenital heart disease in 76,301 mixed-breed dogs and 57,025 mixed-breed cats.

OBJECTIVE: Assess the prevalence of congenital heart disease (CHD) in a large population of mixed-breed dogs and cats. ANIMALS: 76,301 mixed-breed dogs and 57,025 mixed-breed cats. METHODS: Retrospective review of records and examinations based on specified diagnostic criteria. RESULTS: Among mixed-breed dogs, the prevalence of CHD was 0.13% (51.4% female) and of innocent murmurs was 0.10% (53.0% male). Pulmonic stenosis was the most common defect followed by patent ductus arteriosus, aortic stenosis, and ventricular septal defect. Among mixed-breed cats, prevalence of CHD was 0.14% (55.2% male) and of innocent murmurs was 0.16% (54.4% male). When the 25 cats with dynamic left or right ventricular outflow obstruction were counted with cases of innocent murmurs, the overall prevalence was 0.2%. Ventricular septal defects were the most common feline CHD followed closely by aortic stenosis and hypertrophic obstructive cardiomyopathy. There was no overall sex predilection for CHD in mixed-breed cats or dogs, and no significant difference in CHD prevalence between cats or dogs. Among dogs, subvalvular aortic stenosis and mitral valve dysplasia had a male predisposition while patent ductus arteriosus had a female predisposition. Among cats, valvular pulmonic stenosis, subvalvular and valvular aortic stenosis, and ventricular septal defects had a male predisposition while pulmonary artery stenosis had a female predisposition. CONCLUSIONS: The prevalence of CHD in a mixed-breed dogs and cats is lower than for prior studies, perhaps due to the lack of purebreds in the study population or actual changes in disease prevalence.

Cardiac involvement secondary to mediastinal lymphoma in a cat: regression with chemotherapy.

Mediastinal lymphoma with neoplastic invasion into the heart was diagnosed in a 9-year-old castrated male domestic short hair cat. The neoplastic infiltrate was seen throughout the atria and atrial septum, surrounded the aortic root, and resulted in narrowing of the right ventricular outflow tract. Chemotherapy resulted in resolution of the echocardiographic abnormalities and the cat's clinical signs until the patient was euthanized 58 days later following development of neurologic signs. Mediastinal lymphoma with myocardial invasion and response to chemotherapy has not been documented previously in the veterinary literature.

Atrioventricular septal defects: natural history, echocardiographic, electrocardiographic, and radiographic findings in 26 cats.

OBJECTIVES: To evaluate signalment, echocardiographic, electrocardiographic, and radiographic findings as well as natural history in a group of cats with atrioventricular septal defects (AVSD). ANIMALS: 26 client owned cats. METHODS: Medical records were reviewed retrospectively for signalment, morphologic type of AVSD, presence of concurrent congenital heart disease (ConcCHD), diagnostic findings, and natural history. RESULTS: Seventeen cats had an isolated AVSD; 13/17 had a partial and 4/17 had a complete AVSD. Double outlet right atrium (DORA) was diagnosed in 4/17 cats. Of those with a partial AVSD, 7/13 had an atrial communication while 6/13 had a ventricular communication. Congestive heart failure (CHF) developed in 5/17 cats; all 3 cats diagnosed with a DORA not lost to follow-up developed pulmonary edema. Sudden death was documented in 4/17 (23.5%). The 5 year survival was 53.0% (9/17). Concurrent congenital heart disease was identified in 9/26 cats with 7/9 having a conotruncal abnormality. Electrocardiography was performed in 14 cats with 11/14 diagnosed with a conduction disturbance. CONCLUSIONS: Overall the echocardiographic and electrocardiographic findings with AVSD are similar to that seen in humans. Cats may have a higher prevalence than humans of partial AVSD with ventricular communication only as well as a higher prevalence of DORA. Cats with an AVSD have an overall guarded prognosis although some can live for a protracted time.

Hepatic vein stenosis (Budd-Chiari syndrome) as a cause of ascites in a cat.

A 10-year-old cat presented with a history of unexplained ascites. Ultrasound and angiography identified an isolated stenosis of the middle hepatic vein resulting in Budd-Chiari Syndrome. Balloon dilation of the stenosis was attempted but the patient expired. Necropsy revealed a discrete membranous stenosis at the junction of the caudal vena cava and the middle hepatic vein. The literature was reviewed to assess clinical and diagnostic findings, as well as therapeutic options in humans with hepatic vein stenosis.

Primary pulmonic infundibular stenosis in 12 cats: natural history and the effects of balloon valvuloplasty.

OBJECTIVES: To evaluate the natural history of primary pulmonic infundibular stenosis in cats and the effects of balloon valvuloplasty. BACKGROUND: Primary pulmonic infundibular stenosis is an uncommon congenital defect in cats. The natural history of the disease has not been described. Information regarding balloon valvuloplasty in the cat is limited. ANIMALS: Records between January 1, 1999 and December 31, 2005 were reviewed and cats with a confirmed echocardiographic diagnosis of primary pulmonic infundibular stenosis, a complete medical history, and no evidence of significant systemic disease were identified. METHODS: Echocardiographic, electrocardiographic, and radiographic findings are described. The natural history of those with severe disease was compared to those with mild to moderate disease. Balloon valvuloplasty was performed in six of the cats. The technique used is described. RESULTS: A stenotic gradient >or=70 mmHg and a right ventricular outflow tract (measured at the level of the stenosis) to pulmonary valve annulus ratio of

Clinical and echocardiographic findings of pulmonary artery stenosis in seven cats.

OBJECTIVES: Describe the clinical, electrocardiographic (ECG), radiographic and echocardiographic findings in cats with isolated pulmonary artery stenosis. Assess the usefulness of systolic and diastolic Doppler measurements at predicting stenosis severity. BACKGROUND: Pulmonary artery stenosis is an infrequent congenital cardiac defect in humans that has not been reported in cats. In humans, pulmonary artery stenosis is usually seen in conjunction with other cardiac defects and may lead to clinical signs if severe. ANIMALS, MATERIALS AND METHODS: Seven cats with pulmonary artery stenosis were retrospectively evaluated. Medical records, radiographs, ECGs, echocardiograms and angiocardiograms were reviewed. Severity of stenosis was assessed by two-dimensional and color Doppler echocardiographic evaluation and clinical findings. Peak systolic and diastolic gradients across the stenosis, and systolic and diastolic pressure decay half-times were graded using echocardiography. In addition, the duration of antegrade flow during diastole was subjectively assessed. Univariate analyses were performed to assess the best variable to predict stenosis severity. RESULTS: Concurrent congenital defects were not identified. Only cats with severe obstruction showed clinical signs including exertional dyspnea and lethargy. Diastolic Doppler measurements were superior to systolic measurements at predicting severity of stenosis. Antegrade flow throughout diastole and/or a diastolic pressure half-time of >100 ms indicated severe obstruction. The prognosis for pulmonary artery stenosis appears to be good regardless of severity. CONCLUSION: Among cats with pulmonary artery stenosis, clinical signs are uncommon and prognosis is good. Doppler assessment of diastolic flow appears to be superior to systolic flow at predicting severity.

Signalment, clinical signs, and prognostic indicators associated with high-grade second- or third-degree atrioventricular block in dogs: 124 cases (January 1, 1997-December 31, 1997).

OBJECTIVE: To evaluate signalment, clinical signs, and prognosis associated with high-grade second- or third-degree atrioventricular block (AVB) in dogs. DESIGN: Retrospective case series. ANIMALS: 124 dogs. PROCEDURES: Data were gathered from ECGs, veterinarian questionnaires, echocardiograms, and radiographs submitted for review; compared with data from a large control group; and examined for association between variables and duration of survival. A new classification system for AVB was evaluated. RESULTS: Afghan, Catahoula Leopard Dog, Chow Chow, Cocker Spaniel, German Wirehaired Pointer, and Labrador Retriever breeds were predisposed to high-grade second- or third-degree AVB. Heavier, older, and sexually intact female dogs were overrepresented in the study group. Weakness, lethargy, exercise intolerance, and syncope were the most common clinical signs. The presence of clinical signs was not associated with duration of survival. Dogs with high-grade second-degree AVB had a duration of survival similar to that of dogs with third-degree AVB. Dogs with high-grade second- or third-degree AVB were at high risk for sudden death in the first 6 months after diagnosis. High ventricular escape rhythm rate and narrow escape-complex QRS width were negatively associated with duration of survival. Pacemaker implantation had a significant positive association with survival. CONCLUSIONS AND CLINICAL RELEVANCE: Pacemaker implantation should be strongly considered in all dogs with high-grade second- or third-degree AVB regardless of whether clinical signs are evident. If medical treatment is warranted, vagolytic medications may be the best choice. A new classification system for AVB may merit further investigation.

Balloon valvuloplasty of valvular pulmonic stenosis in the dog.

Balloon valvuloplasty has become the accepted method of therapy for the majority of dogs with valvular pulmonic stenosis. Success rate of balloon valvuloplasty is excellent but the procedure can have a steep learning curve. An understanding of the equipment used and specifics of the procedure is important to maximize success and minimize risk. This paper will review criteria for choosing candidates for balloon valvuloplasty, discuss the equipment used, discuss the procedure in detail, and finally discuss assessment of success and possible complications.