Cardiac disease in the geriatric horse.

Almost all equine cardiac diseases may affect the geriatric horse. This article focuses on those cardiac diseases that are most common in the older horse, including degenerative valve disease, aortocardiac fistula, and congestive heart failure. Other cardiac diseases, such as bacterial endocarditis, pericarditis, and arrhythmias, are seen in all age groups of horses and are beyond the scope of this article.     

Fluid therapy in patients with pulmonary disease.

Fluid therapy in patients with pulmonary disease is challenging. Although a single set of rules cannot be applied to every patient, the following guidelines can be used when managing patients with pulmonary disease. Euvolemic patients with adequate tissue perfusion should be given sufficient isotonic fluid to balance insensible losses. If severe pulmonary compromise is present, cessation of all fluid therapy may be considered if the patient is able to match its losses by voluntary intake. In hypovolemic or hypotensive patients, small boluses of isotonic crystalloids or colloids should be given to restore perfusion, avoiding rates of more than 30 mL/kg an hour for isotonic crystalloids. If perfusion is not restored by adequate volume resuscitation, vasopressors or positive inotropes should be administered to prevent fluid overload and deterioration in pulmonary function.     

Nutritional considerations for animals with pulmonary disease.

Recent publications in the human and veterinary literature have indicated that patients with pulmonary disease require specific nutritional consideration to ensure that optimal benefit is derived with nutrition support. Although additional research is needed in this area, preliminary recommendations can be made using information from the scant studies performed thus far in veterinary medicine and from information extrapolated from the human literature. These recommendations are likely to provide significant clinical benefit to patients with pulmonary disease. This article aims to provide the reader with a summary of the available information and links to other relevant sources.     

Fatal mycotic pulmonary disease of captive American alligators.

Fatal pulmonary disease occurred in two captive American alligators. The entomopathogenic fungus, Beauveria bassiana, was isolated from pulmonary lesions in both alligators. An extended hibernation period because of a severe winter and a failure of the zoo heating system may have predisposed the alligators to infection.     

Acute eosinophilic interstitial pulmonary disease in a pony.

An outdoor pony which developed severe respiratory distress in February was shown to have acute interstitial pulmonary disease (alveolitis), which was characterised by a massive exudation of eosinophil rich fluid into the airways. While antibiotic treatment before referral was ineffective, the condition rapidly responded to corticosteroid therapy. No evidence of lungworm was present and it appears that this interstitial pulmonary disease had an immune-mediated aetiology. Bronchoalveolar lavage cytology was of great value in the diagnosis and monitoring of this case.     

Chronic pulmonary disease in West Highland white terriers.

This paper describes the clinical features, and diagnostic findings of a chronic respiratory condition in 29 West Highland white terriers. Typically, the dogs were coughing chronically, had dyspnoea and tachypnoea of varying severity, and had deteriorated progressively over months to years. The mean (sem) survival time in months from the clinical signs being first noted by the owners was 17.9 (2.3). Most cases had a combination of respiratory signs, but coughing was the predominant sign in 18 cases. Inspiratory crackles were audible on chest auscultation in 28 cases, 10 of which were also wheezing. Rhonchi were the predominant sound in the remaining case. The main radiographic changes were mild to severe increased Interstitial markings in all cases, with additional bronchial markings in 14 of the dogs. Right-sided cardiomegaly (cor pulmonale) was recorded in 15. Bronchoscopic findings in 17 of the dogs were either normal or involved a mild airway mucoid reaction in eight. Chronic mucosal changes were observed in eight, but in two this finding was equivocal. Dynamic changes to the lumen of the airway were present in seven cases. No significant haematological or biochemical changes could be detected in 20 cases, but four cases were hypercholestrolaemic. A histopathological assessment of four cases revealed alveolar septal fibrosis to be the predominant change. Prednisolone, with or without bronchodilators, was the most commonly used therapy, and the response was variable. The condition appears to be associated with significant pulmonary interstitial fibrosis of unknown aetiology and has clinical similarities to idiopathic pulmonary fibrosis (cryptogenic fibrosing alveolitis) in human beings.     

Chronic obstructive pulmonary disease

COPD continues to be a severe condition in horses. Despite increased understanding of its pathogenesis, there is relatively little information on effective treatment regimens. Management and prevention are critical, and more emphasis should be placed on improved housing, bedding, and feeding. More sophisticated accurate methods also are required for identifying specific causative allergens.     

Cardiac musculature of the cranial and caudal venae cavae and the pulmonary vein in the fowl.

The cardiac musculature of cranial and caudal venae cavae and pulmonary vein was examined to clarify its distribution pattern in the fowl using both light and electron microscopies. The musculature was distributed from the heart to the root of subclavian vein in the cranial vena cava, to the cranial margin of the liver in the caudal vena cava, and to the left and right distal pulmonary veins in the pulmonary vein, respectively. Judging from the morphology and distribution pattern in the venous wall, the cardiac musculature in the fowl is thought to share the same phylogenic origin with that in mammals. The ultrastructure of cardiac myocytes including transitional cells in the cranial vena cava and the pulmonary vein resembled that of atrial myocytes. While, the typical specialized myocytes such as Purkinje fiber were found in the caudal vena cava of the fowl.     

Clinical impressions of canine pulmonary disease

The clinical methods of diagnosis are described and it is emphasized that their useful application increases with practice. Details are given of relevant cases seen during a period of 6 months. There were two cases of bronchitis, two cases of pulmonary congestion, secondary to cardiac insufficiency, one of inflammation due to migrating roundworm larvae and two cases of tumour metastasis. Résumé. On décrit les méthodes cliniques de diagnostic et on souligne le fait que l'utilité de leur emploi augmente avec l'augmentation de la pratique. On donne des détails des cas caractéristiques observés au cours d'une période de 6 mois; il s'agissait de deux cas de bronchite, de deux cas de congestion pulmonaire secondaire à une insuffisance cardiaque, d'un cas d'inflammation due à la migration de larves d'Ascaris et de deux métatases de tumeurs. Zusammenfassung. Die klinischen Methoden der Diagnose werden beschrieben, und es wird betont, dass mit zunehmender Praxis sich ihre erfolgreiche Anwendung verbessert. Einzelheiten über aufschlussreiche Fälle in einem Zeitraum von 6 Monaten werden angegeben. Es handelte sich um zwei Fälle von Bronchitis, zwei Fälle von Lungenstauung nach Herzinsuffizienz, einen von Entzündung infolge wandernder Fadenwurmlarven und zwei Fälle von metastatischem Tumor.     

Beta-adrenergic receptor activity in ponies with recurrent obstructive pulmonary disease.

Pulmonary function measurements were made in control ponies and in ponies with recurrent obstructive pulmonary disease (principals) during clinical remission and during an attack of acute airway obstruction. The ponies were given beta-adrenergic antagonists and agonists to determine the role of beta receptors in recurrent obstructive pulmonary disease, and to determine the subtypes of beta receptors mediating bronchodilation in ponies. Aerosol administration of the beta antagonists, propranolol (beta 1 and beta 2), atenolol (beta 1), and butoxamine (beta 2) decreased dynamic compliance (Cdyn) and increased pulmonary resistance (RL) in the principal ponies during airway obstruction, but were without effect when the ponies were in clinical remission. Intravenous administration of atropine reversed the effect of atenolol on Cdyn and RL, but was without effect on the decrease in Cdyn and increase in RL observed after butoxamine administration. The beta antagonists did not affect airway function in the control ponies. The effect of beta blockade on Cdyn and RL suggests beta-adrenergic activation in the central and peripheral airways of principal ponies, mediated through both beta 2- and beta 1-adrenergic receptors. The aerosol beta agonists, isoproterenol (beta 1 and beta 2), and clenbuterol (beta 2) attenuated histamine-induced airway obstruction to a similar extent in control ponies that were given histamine IV. In addition, the beta 1 antagonist, atenolol, did not attenuate the bronchodilation observed with isoproterenol. We concluded that, although beta 1- and beta 2-adrenergic receptors exist in pony airways and are activated during acute airway obstruction, bronchodilation in response to beta agonists in ponies seems to be mediated primarily by beta 2-adrenergic receptors.     

Chronic obstructive pulmonary disease in the horse. 2: Therapy

The therapy of equine chronic obstructive pulmonary disease (COPD) essentially entails minimising the horse's exposure to the aetiological antigens which are predominantly thermophilic actinomycetes and moulds occurring in hay and straw. This can be achieved, for example, by keeping affected horses permanently out of doors, or when stabled, using shredded paper, wood shavings or peat moss as bedding and feeding a complete cubed diet. There should be no supplementary hay feeding apart from dust-free vacuum-packed hay. Applying such measures generally allows horses to become asymptomatic in seven to 14 days. Bronchodilators and corticosteroids bring about a marked, but temporary, improvement and can be of value in the treatment of acute attacks. The use of oral bronchodilators in combination with environmental control measures may hasten the remission of clinical signs in affected horse. Inhaled sodium cromoglycate can be used prophylactically in asymptomatic horses to prevent the onset of COPD when unavoidable antigen exposure is anticipated.     

Relationship between pulmonary arterial pressure and pulmonary thromboembolism associated with dead worms in canine heartworm disease.

To examine effects of thromboemboli due to dead worms on pulmonary arterial pressure (PAP), 20 to 50 dead heartworms were inserted into the pulmonary arteries of 4 heartworm uninfected dogs (uninfected group) and 11 dogs infected with heartworms (infected group). In the uninfected group, the mean PAP rose 1 week after worm insertion (10.9 to 166. mmHg), but it recovered by the 4th week. Clinical signs, hemodynamics and blood gas findings also deteriorated at the 1st week, but recovered at the 4th week. Angiographic and pathological findings indicated that blood flow recovered through the spaces between thromboemboli and vessel walls at the 4th week. The infected dogs were divided into three groups. In the infected-I group (5 dogs), the intimal lesions of the pulmonary arteries were slight, and clinical and laboratory findings showed changes similar to those of the uninfected group. In the infected-II group (4 dogs), the pulmonary arterial lesions were severe and the mean PAP was higher (25.7 mmHg) than in the uninfected group before worm insertion. An increase in PAP (34.1 mmHg) and worsening of clinical and laboratory findings were noticed till the 4th week. Thromboemboli adhered extensively to the vessel walls. Two dogs in the infected-III group died of severe dyspnea on the 9th and 10th day, and the mean PAP rose remarkably at the 1st week (from 19.4 to 28.2 mmHg). Severe pulmonary parenchymal lesions with edema or perforation were observed. From the above results, it was clarified that effects of dead worms on PAP and clinical signs depended on the severity of pulmonary arterial lesions before worm insertion.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cardiac troponin-I concentration in dogs with cardiac disease

Cardiac troponin-I (cTnI) is a highly sensitive and specific marker of myocardial injury and can be detected in plasma by immunoassay techniques. The purpose of this study was to establish a reference range for plasma cTnI in a population of healthy dogs using a human immunoassay system and to determine whether plasma cTnI concentrations were high in dogs with acquired or congenital heart disease, specifically cardiomyopathy (CM), degenerative mitral valve disease (MVD), and subvalvular aortic stenosis (SAS). In total, 269 dogs were examined by physical examination, electrocardiography, echocardiography, and plasma cTnI assay. In 176 healthy dogs, median cTnI was 0.03 ng/mL (upper 95th percentile = 0.11 ng/mL). Compared with the healthy population, median plasma cTnI was increased in dogs with CM (0.14 ng/mL; range, 0.03-1.88 ng/mL; P < .001; n = 26), in dogs with MVD (0.11 ng/mL; range, 0.01-9.53 ng/mL; P < .001; n = 37), and in dogs with SAS (0.08 ng/mL; range, 0.01-0.94 ng/mL; P < .001; n = 30). In dogs with CM and MVD, plasma cTnI was correlated with left ventricular and left atrial size. In dogs with SAS, cTnI demonstrated a modest correlation with ventricular wall thickness. In dogs with CM, the median survival time of those with cTnI >0.20 ng/mL was significantly shorter than median survival time of those with cTnI <0.20 ng/mL (112 days versus 357 days; P = .006). Plasma cTnI is high in dogs with cardiac disease, correlates with heart size and survival, and can be used as a blood-based biomarker of cardiac disease.     

Cardiovascular and pulmonary effects of atropine reversal of oxymorphone-induced bradycardia in dogs.

Oxymorphone was administered intravenously (IV) to 10 dogs (0.4 mg/kg initial dose followed by 0.2 mg/kg three times at 20-minute intervals). Four hours after the last dose of oxymorphone, heart rates were less than 60 bpm in six dogs. After atropine (0.01 mg/kg IV) was administered, heart rate decreased in five dogs and sinus arrhythmia or second degree heart block occurred in four of them. A second injection of atropine (0.01 mg/kg IV) was administered 5 minutes after the first and the heart rates increased to more than 100 bpm in all six dogs. Ten minutes after the second dose of atropine, heart rate, cardiac output, left ventricular minute work, venous admixture, and oxygen transport were significantly increased, whereas stroke volume, central venous pressure, systemic vascular resistance, and oxygen extraction ratio were significantly decreased from pre-atropine values. The PaCO2 increased and the PaO2 decreased but not significantly. The oxymorphone-induced bradycardia did not produce any overtly detrimental effects in these healthy dogs. Atropine reversed the bradycardia and improved measured cardiovascular parameters.     

Intradermal testing of horses with chronic obstructive pulmonary disease and recurrent urticaria.

Six horses with chronic obstructive pulmonary disease (COPD) and 8 horses with recurrent urticaria were skin tested with 67 extracts from 58 allergens, including pollens, epidermals, cultivated farm plants, dusts, molds, and insects. Reactions were evaluated 3 times over a 24-hour period immediately after the injections. Results were compared with those obtained from 11 clinically normal horses. All horses had positive skin test reactions. Significant differences was evident between horses with COPD and clinically normal horses for only 3.0% of the possible extract reactions, and between horses with urticaria and clinically normal horses for only 4.5% of the possible extract reactions. Horses with COPD or urticaria had greater total percentage of allergen extract reactions than did clinically normal horses. Positive reactions were observed at all 3 evaluation periods, and late-onset reactions were not always preceded by positive reaction at earlier periods. All horses with COPD or urticaria had at least 1 skin test reaction that exceeded the mean +/- 2 SD, as calculated for each of the 67 extracts for the group of clinically normal horses.