Metabolic and structural abnormalities in dogs with early left ventricular dysfunction induced by incessant tachycardia

OBJECTIVE: To assess morphologic and metabolic abnormalities in dogs with early left ventricular dysfunction (ELVD) induced by rapid right ventricular pacing (RRVP). ANIMALS: 7 Beagles. PROCEDURE: Plasma carnitine concentrations were measured before and after development of ELVD induced by RRVP. At the same times, transvenous endomyocardial biopsy was performed, and specimens were submitted for determination of myocardial carnitine concentrations and histologic, morphometric, and ultrastructural examination. RESULTS: In 4 dogs in which baseline plasma total carnitine concentration was normal, RRVP induced a decrease in myocardial total and free carnitine concentrations and an increase in myocardial esterified carnitine concentration. In 3 dogs in which baseline plasma total carnitine concentration was low, plasma and myocardial carnitine concentrations were unchanged after pacing. Structural changes associated with pacing included perinuclear vacuolization in 3 dogs. Morphometric analyses indicated there was a decrease in myofiber cross-sectional diameter and area following pacing. Electron microscopy revealed changes in myofibrils and mitochondria following pacing. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that moderate to severe alterations in myocyte cytoarchitecture are present in dogs with ELVD induced by RRVP and that in dogs with normal plasma carnitine concentrations, myocardial carnitine deficiency may be a biochemical marker of ELVD. Results also indicated that transvenous endomyocardial biopsy can be used to evaluate biochemical and structural myocardial changes in dogs with cardiac disease.     

A retrospective study of non-specific rhinitis in 22 cats and the value of nasal cytology and histopathology

Case records from 40 cats subjected to rhinoscopic examination for investigation of chronic nasal disease were reviewed. Cases in which no specific underlying cause (eg neoplasia) was detected were further selected for detailed retrospective study. In these 22 cats (55% of the initial population), a final diagnosis of non-specific chronic nasal disease was made. The radiographic, rhinoscopic, cytological and histopathological findings were reviewed. Mucosal biopsy specimens were obtained in 20 cases. Despite clinical signs of more than 4 weeks duration, histopathology indicated acute inflammation in four cases. Two cases had chronic lymphoplasmacytic inflammation and 14 had mixed (lymphoplasmacytic and neutrophilic) inflammation. Specimens for cytology were obtained from 17 cases by brush sampling. Three of these samples were not diagnostic due to the poor quality of the slides; one showed normal cytology. Acute inflammation was diagnosed by cytology (n=11) more commonly than chronic (n=1) or mixed inflammation (n=1). Concurrent samples, of quality suitable for both histopathological and cytological interpretation, were collected from 12 cases only. Cytological results were in agreement with the histological results in 25% of these cases, the main discrepancy being the nature of the dominant inflammatory cell type. Therefore cytology does not appear to be a reliable means for detection of chronic inflammation. Further studies are needed in order to investigate the correlation between the nature of mucosal inflammation as defined by both histological and cytological evaluation, and the relationship of these test results to prognosis and therapy.     

Resolution of chylothorax after resection of rib chondroma in a dog

A six-year-old, male dobermann was presented with a history of dyspnoea and bouts of coughing. Radiography and computed tomography of the thorax showed pleural effusion and a well-circumscribed, calcified mass of 10 cm in diameter, appearing to originate from the left first rib. Thoracocentesis revealed that the pleural fluid was chylous in nature. An incisional biopsy was performed, which gave a histological diagnosis of chondroma. Resolution of the chylothorax after en-bloc surgical removal of the tumour suggested that the rib tumour was the initiating cause of the chylothorax. Seventeen months later, rib neoplasia recurred without pleural effusion, and was removed successfully. To the authors' knowledge, rib chondroma, which is an unusual tumour in dogs, has not been previously documented as a cause of chylothorax.     

Pulmonary Vein‐to‐Pulmonary Artery Ratio is an Echocardiographic Index of Congestive Heart Failure in Dogs with Degenerative Mitral Valve Disease

Background

Early recognition of left‐sided congestive heart failure (CHF) in dogs with degenerative mitral valve disease (DMVD) is important because it influences medical therapy, timing of follow‐up, and outcome.

Hypothesis

Pulmonary vein diameter‐to‐pulmonary artery diameter ratio (PV/PA) measured by echocardiography can predict CHF.

Animals

Ninety‐eight client‐owned dogs, 37 controls, and 61 dogs with DMVD.

Methods

Prospective clinical cohort study. History, physical examination and Doppler‐echocardiography were performed. Dogs were classified as International Small Animal Cardiac Health Council class I, II or III. Congestive heart failure was identified in a subset of 56 dogs based on radiographic findings. The PV/PA was measured in bidimensional (2D) and M‐mode by 2 investigators blinded to the radiologists’ conclusions.

Results

Interobserver coefficients of variation for PV/PA acquisition and measurement were <10%. The PV/PA in control dogs was approximately 1 and increased with class of heart failure. The presence of CHF could be best predicted by measuring PV/PA in 2D echocardiography (cut‐off, 1.7; area under the curve, 0.98; CI, 0.97–0.98; P < .001) with a sensitivity of 96% and a specificity of 91%.

Conclusion and clinical importance

The PV/PA is a simple and reproducible echocardiographic variable that increases with class of heart failure and may help discriminate dogs in CHF from asymptomatic dogs with DMVD. Additional studies are required to determine whether PV/PA might provide additional information in the integrated interpretation of Doppler‐echocardiographic indices of left ventricular filling pressures and could be used for rapid assessment of CHF in dogs in a critical care setting.     

The topographical distribution of the inhalation-to-perfusion ratio in double-muscled and Friesian calves

Five healthy Friesian calves and five double-muscled Belgian White and Blue calves were studied, using a 99m Technetium (99mTc) aerosol inhalation combined with a 99mTc macroaggregate injection and collimated scintillation counters. The inhalation-to-perfusion ratio (I/P) was calculated for both left and right sides of the thorax at four sites situated at three different levels in the auscultatory area on the same vertical axis and at a more anterior site just behind the scapulohumeral joint.I/P was higher in the left than in the right hemithorax. In both breeds, a vertical and a horizontal gradient were observed. I/P was higher in the lower and in the more cranial zones of the lungs. However the vertical gradient was more pronounced in Friesian calves while the horizontal one was greater in Belgian White and Blue animals.It was concluded that the factors affecting the topographical distribution of pulmonary ventilation and perfusion seem to be different in calves as compared to other species.     

Collection of exhaled breath condensate and analysis of hydrogen peroxide as a potential marker of lower airway inflammation in cats

The objective of this study was to describe a standardised and non-invasive method for exhaled breath condensate (EBC) collection in cats and to test whether determination of hydrogen peroxide (H(2)O(2)) in EBC might be used as marker of lower airway inflammation. The technique of barometric whole body plethysmography for cats was combined with a system to condense the effluent air from the plethysmograph, allowing simultaneous EBC collection and respiratory pattern measurement. H(2)O(2) was determined spectrophotometrically. Eighteen experimental cats were used to investigate the impact on EBC volume and EBC H(2)O(2) of plethysmograph ventilation rate, collection duration, sample stability, within-day and day-to-day variability. After determination of a standardised EBC collection procedure, correlation analyses between EBC H(2)O(2) and bronchoalveolar lavage (BAL) cytology of healthy and allergen-challenged Ascaris suum (AS)-sensitised cats were performed. A significant and positive correlation between EBC H(2)O(2) and bronchoalveolar lavage (BAL) neutrophil% was found in healthy cats (P < 0.001, r = 0.55), whereas in AS-sensitised cats, correlation with BAL eosinophil% was significant (P < 0.005, r = 0.61). H(2)O(2) was increased after an allergen challenge in AS-sensitised cats (n = 6, 0.56+/-0.12 versus 1.08+/-0.35 micromol/L, P < 0.05). This study proposes a non-invasive, well tolerated and repeatable method of EBC collection for cats and suggests that EBC H(2)O(2) might be used as non-invasive biomarker for monitoring lower airway inflammation.     

Laryngeal paralysis-polyneuropathy complex in young related Pyrenean mountain dogs

OBJECTIVES: To characterise clinical, electrophysiological and histopathological findings. To analyse pedigree information in six young related Pyrenean mountain dogs with laryngeal paralysis-polyneuropathy complex (LP-PNC). METHODS: A retrospective study of clinical records and pedigrees of six young related Pyrenean mountain dogs with LP-PNC was carried out. RESULTS: All dogs were presented with laryngeal paralysis and concurrent megaoesophagus. Electrodiagnostic testing was performed in three dogs and showed electrophysiological abnormalities in the distal appendicular muscles. Histopathological findings of peripheral nerve samples were dominated by distal axonal degeneration. Clinical, electrophysiological and histopathological findings were supportive of a diagnosis of degenerative, sensorimotor LP-PNC, similar to that reported in young dalmatians and rottweilers. All dogs died or were euthanased by two years of age. An autosomal recessive mode of inheritance was suspected based on pedigree analysis. CLINICAL SIGNIFICANCE: Congenital LP-PNC should be suspected in any young dog presenting with laryngeal dysfunction and other concurrent neurological abnormalities. The prognosis is usually poor.     

Surgical treatment of canine nasal aspergillosis by rhinotomy combined with enilconazole infusion and oral itraconazole

OBJECTIVES: To evaluate the effectiveness of rhinotomy and surgical debridement associated with topical administration of 2 per cent enilconazole and oral itraconazole in dogs with severe or recurrent sinonasal aspergillosis. METHODS: A standard rhinotomy was performed on seven dogs. In the initial study, the bone flap was left attached cranially and replaced at the end of the procedure. In the main study group, the bone flap was discarded. Nasal passages were debrided and irrigated with enilconazole solution for one hour. Oral itraconazole was administered to four dogs for one month postoperatively. Follow-up rhinoscopy was performed in all dogs. RESULTS: All three dogs in the initial study had recurrence of the disease and two dogs had a second surgery to remove the flap. The main study group included four dogs in which the flap was initially removed, and the two dogs from the initial study that required a second surgery. At follow-up rhinoscopy, five dogs were free of aspergillus but had bacterial or inflammatory rhinitis and one dog had a small aspergilloma but was subsequently asymptomatic. Telephone follow-up revealed that four dogs were asymptomatic, one dog had intermittent sneezing and serous nasal discharge, and one dog had intermittent epistaxis. CLINICAL SIGNIFICANCE: Rhinotomy with removal of the flap combined with one-hour infusion of 2 per cent enilconazole and oral itraconazole resulted in satisfactory outcome in dogs with severe or recurrent aspergillosis.