Chronicity of atrial fibrillation affects duration of sinus rhythm after transthoracic cardioversion of dogs with naturally occurring atrial fibrillation

BACKGROUND: Atrial fibrillation (AF) in dogs can be managed by electrical cardioversion to sinus rhythm, but early recurrence of AF occurs in some dogs. In humans, the commonly evaluated clinical variables for prediction of early relapse of AF are left atrial size and duration of AF. It is unclear whether the duration of AF affects maintenance of sinus rhythm after cardioversion in dogs with spontaneous AF. HYPOTHESIS: That duration of sinus rhythm after cardioversion is related to the chronicity of AF. ANIMALS: Forty-one consecutive dogs that had undergone successful transthoracic cardioversion for spontaneous AF were evaluated. METHODS: The relationship between the duration of documented AF and the duration of sinus rhythm after cardioversion was statistically evaluated using data obtained retrospectively. The effects of structural heart disease and pretreatment with amiodarone were also evaluated. RESULTS: The presence of structural heart disease and the duration of documented AF had significant effects on maintenance of sinus rhythm after cardioversion (P <.001 and P=.022, respectively). The duration of documented AF was inversely related to the duration of sinus rhythm (P=.022) in dogs with and without structural heart disease. CONCLUSIONS AND CLINICAL IMPORTANCE: Estimates of duration of sinus rhythm based on the duration of documented AF are provided for dogs with and without heart disease allowing prediction of risk for early AF relapse.     

Insulinoma in a cat

A 14-year-old domestic shorthair cat was presented with hypoglycaemia and seizures of several weeks duration. Bloodwork revealed hypoglycaemia (1.83 mmol/l; reference range 4.22-8.05 mmol/l) with concurrent normal insulin levels (171 pmol/l; reference range 72-583 pmol/l). An insulinoma was suspected and medical and dietary management were attempted with minimal success. An exploratory laparotomy was performed and a single, well-defined mass was found within the left lobe of the pancreas. The mass was removed and histologically classified as an islet cell carcinoma, consistent with an insulinoma. The cat had an episode of presumed postoperative pancreatitits, but recovered with appropriate treatment. The cat has had no clinical signs of recurrence of greater than 32 months postsurgery. There are only four cases of insulinoma in cats reported in the literature. All prior insulionomas reported were in older cats and were malignant in character, which is similar to the reports in the dog. This case is unique because of the apparent lack of local recurrence and development of metastatic disease, leading to the prolonged survival.     

Effects of Graded Levels of Carbohydrate on Growth and Survival of Largemouth Bass, Micropterus salmoides

Excessive carbohydrates (CHO) in diets for largemouth bass (LMB), Micropterus salmoides, are suspected of accumulating glycogen in hepatocytes, which may result in liver dysfunction. This study evaluated the effect of graded levels of dietary CHO on growth, survival, and liver histology of LMB. One hundred feed‐trained advanced fingerling LMB (128.5 ± 21.5 g) were stocked into each of nine 3400 ‐ L polyethylene tanks. Tanks were randomly assigned one of three experimental diets containing different CHO levels (13, 19, or 25% of diet). The extruded diets were approximately isonitrogenous (42% crude protein) and isocaloric (3 kcal/g energy). There were three replicate tanks per dietary treatment. Bass were fed to apparent satiation twice daily for 148 d. Survival was significantly higher (P ≤ 0.05) for fish fed the 13 and 19% CHO diets (89 and 90%, respectively) compared to those fed the 25% CHO diets (82%). Average harvest weight of fish fed the 13% CHO diet (380 g) was significantly greater (P ≤ 0.05) than for fish fed other diets. Average harvest weight of fish fed the 19% CHO diet (347 g) was significantly greater (P ≤ 0.05) than for fish fed the 25% CHO diet (310 g). Specific growth rates (%/d) were significantly higher (P ≤ 0.05) in fish fed the 13 and 19% CHO diets than in fish fed 25% CHO diet. Feed conversion ratios for fish fed the 13 and 19% CHO diets (2.3 and 2.4, respectively) were both significantly lower (P ≤ 0.05) than in fish fed the 25% CHO diet (3.6). There were no significant differences (P > 0.05) in condition factor, protein efficiency ratio, hepatosomatic index, or liver glycogen concentration among fish fed the different experimental diets. Overall, mean blood glucose levels in fish fed the 13 and 19% CHO diets (61.0 and 71.2 mg/dL, respectively) were significantly lower (P ≤ 0.05) than in fish fed the 25% CHO diet (87 mg/dL). Histopathological examination of livers from fish fed the three diets was used to score the degree of vacuolization of hepatic tissues (0 = normal, 1 = slight, 2 = mild, 3 = moderate, and 4 = severe). Regression of vacuolization scores on dietary CHO levels was statistically significant (P ≤ 0.05) and indicated a direct positive relationship between liver vacuolization and dietary CHO level (R² = 0.57). These data indicate that LMB grow faster and use feeds more efficiently when CHO are maintained at <20% of diet. CHO levels >20% negatively impacted liver histology, but a liver tissue analyses did not document glycogen accumulation.     

Lymphoid organ cell culture system from Penaeus monodon (Fabricius) as a platform for white spot syndrome virus and shrimp immune-related gene expression

Shrimp cell lines are yet to be reported and this restricts the prospects of investigating the associated viral pathogens, especially white spot syndrome virus (WSSV). In this context, development of primary cell cultures from lymphoid organs was standardized. Poly-l-lysine-coated culture vessels enhanced growth of lymphoid cells, while the application of vertebrate growth factors did not, except insulin-like growth factor-1 (IGF-1). Susceptibility of the lymphoid cells to WSSV was confirmed by immunofluoresence assay using monoclonal antibody against the 28 kDa envelope protein of WSSV. Expression of viral and immune-related genes in WSSV-infected lymphoid cultures could be demonstrated by RT-PCR. This emphasizes the utility of lymphoid primary cell culture as a platform for research in virus-cell interaction, virus morphogenesis, up and downregulation of shrimp immune-related genes, and also for the discovery of novel drugs to combat WSSV in shrimp culture.     

Transcatheter intravascular stent placement to relieve supravalvular pulmonic stenosis

Valvular pulmonic stenosis has been successfully treated in dogs via minimally invasive transcatheter balloon dilation procedures for almost 20 years. Supravalvular pulmonic stenosis however is not amenable to balloon dilation procedures. Although several surgical procedures are described for treatment of pulmonic stenosis, the morbidity and mortality of these procedures are significantly higher than for transcatheter approaches.Two cases of supravalvular pulmonic stenosis are presented, one acquired and one congenital, which were successfully treated with transcatheter intravascular stent placement. The procedure alleviated the stenotic lesion and resolved clinical signs.     

Percutaneous balloon valvuloplasty for treatment of pulmonic stenosis in a dog

A 2.5-year-old dog with congenital pulmonary valve dysplasia was treated by percutaneous balloon dilation of the stenotic orifice. Clinical and hemodynamic improvement was apparent immediately and for 9 months after the valvuloplasty procedure.     

THE USE OF GATED RADIONUCLIDE VENTRICULOGRAPHY AS A NONINVASIVE METHOD OF EVALUATING RIGHT VENTRICULAR FUNCTION IN DOGS WITH EXPERIMENTALLY INDUCED CONGESTIVE HEART FAILURE

Gated radionuclide ventriculography was evaluated as a noninvasive method of quantifying right ventricular function in dogs with experimentally induced congestive heart failure. Gated radionuclide ventriculography measurements of right ventricular function (right ventricular ejection fraction, right ventricular average emptying rate, and right ventricular average filling rate) were related to standard hemodynamic and echocardiographic measurements. Congestive heart failure was induced by rapid ventricular pacing in eight normal dogs. Hemodynamic, echocardiographic, and gated radionuclide ventriculography measurements were obtained before and after development of biventricular failure. Congestive heart failure resulted in significant changes in all hemodynamic, echocardiographic, and gated radionuclide ventriculography measurements with the exception of systemic arterial pressure. Right ventricular ejection fraction was inversely related to pulmonary artery systolic, diastolic, and mean pressure, and right ventricular average emptying rate was inversely related to the pulmonary artery systolic, diastolic, and mean pressure. Right ventricular ejection fraction was inversely related to left ventricular filling pressure, (pulmonary capillary wedge pressure). Neither the echocardiographic measurements of right ventricular size (right ventricular internal diastolic dimension) nor the right ventricular end-diastolic pressure were related to right ventricular ejection fraction and right ventricular average emptying rate. However, echocardiographic measurements of right ventricular dimension were related to right ventricular filling pressure. The gated radionuclide ventriculography indexes of right ventricular function, right ventricular ejection fraction and right ventricular average emptying rate, are affected by afterload but unaffected by preload, whereas the echocardiographic measurement of right ventricular dimension is related to preload. Gated radionuclide ventriculography provides right ventricular data which is unique from that obtained by standard echocardiographic imaging. Also, gated radionuclide ventriculography has potential value as a noninvasive means of estimating a change in pulmonary artery pressure.     

Intrapericardial cyst causing cardiac tamponade in a cat

A two-year-old cat with episodic dyspnea was diagnosed with an intrapericardial cyst via two-dimensional echocardiography. The cyst directly compressed the right ventricle, resulting in cardiac tamponade. Centesis of the cyst was performed to reduce tamponade prior to surgery. At surgery, a large, fluid-filled cystic structure was found within the pericardium. The cystic structure was continuous with a pedicle of liver that passed through a small peritoneopericardial diaphragmatic hernia. Surgical resolution was achieved by median sternotomy, midline pericardotomy, resection of the cyst, and diaphragmatic herniorrhaphy.     

The influence of land management on soil erosion in the Sneeuberg Mountains,Central Karoo,South Africa

Farm practices in the Sneeuberg Mountains, Karoo, South Africa are examined to assess their contribution to the development of the observed gullies and badlands. Data from the literature is augmented by interviews with local farmers and measurements in the field. Changes in stocking rates, grazing systems and technological advances are assessed for their impact on soil erosion, vegetation cover and species composition. The possibility of natural and managed rehabilitation of badland areas is discussed, as are future prospects for farm management in the Sneeuberg. The findings suggest that high stock numbers and less benign management practices in the 19th century and the early 20th century underlie much of the degradation seen today. Copyright © 2007 John Wiley & Sons, Ltd.     

Arthroscopic-assisted management of osteochondritis dissecans in the stifle of a cat

An 11-month-old, male neutered, domestic short-haired cat presented for evaluation of sudden onset right pelvic limb lameness. Radiography showed features consistent with unilateral osteochondritis dissecans (OCD) of the lateral femoral condyle in the right stifle. Arthroscopic examination of the stifle was used to confirm the presence of an articular cartilage lesion and the presence of loose cartilage within the joint. The loose cartilage fragments were removed arthroscopically. One arthroscopy portal was extended into a limited arthrotomy, which was necessary to ensure complete debridement of the defect. Removal of the fragments led to complete resolution of the clinical signs. This case report documents a more minimally invasive technique for the management of stifle OCD in the cat than previously documented and helps to establish a protocol for arthroscopic surgery in the feline stifle.