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  • Author or Editor: Johanna M. Reimer x
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Summary

Nine horses with (naturally acquired) congestive heart failure were treated with 2.2 μg of digoxin/kg of body weight by the Iv route, followed by 11 μg/kg administered orally every 12 hours thereafter. Furosemide was administered IV concurrently with IV administered digoxin every 12 hours. Serum concentration of digoxin was measured after the first (Iv) and seventh (orally administered) dose.

After Iv administration, digoxin disposition was described by a 2-compartment model, with a rapid distribution phase (t1/2α = 0.17 hour), followed by a slower elimination phase (β = 0.096 ± 0.055 h−1, t1/2β = 7.2 hours, where β is the exponential term from the elimination phase of the concentration vs time curve). Bioavailability after oral administration was 21.2 ± 10.8%. After the seventh orally administered dose, serum concentration of digoxin peaked 1 to 2 hours later, and was 1.9 ± 0.7 ng/ml (mean ± sd). In 4 horses, a second increase in serum digoxin concentration was observed 4 to 8 hours after the initial peak, which possibly was evidence of enterohepatic recycling of the drug.

Response to treatment included reduction in heart rate, peripheral edema, and pulmonary edema, but these could not be attributed to the digoxin alone because the horses were treated concurrently with furosemide.

Free access
in American Journal of Veterinary Research

Summary

Ventricular premature depolarizations (vpd) were identified in 21 horses in which unexplained tachycardia or an arrhythmia was detected on auscultation. Horses were categorized into 3 groups on the basis of ecg findings. Seven horses had uniform isolated vpd (group 1); 7 horses had repetitive uniform vpd at a rate <100 vpd/min (group 2); and 7 horses had either multiform vpd, R-on-T, or ≥ 100 vpd/min (group 3). Concurrent systemic disease was identified in 12 horses, 7 of which had gastrointestinal tract disorders. Serum cardiac isoenzyme activities were high in 6 (2 from each group) of 13 horses in which they were measured. Serum electrolyte concentrations were normal in all but 1 of 11 horses in which they were measured.

Antiarrhythmic drugs were given to 9 horses (all of which were in group 2 or group 3), 6 of which converted to sinus rhythm. Two horses that had R-on-T in the ECG died shortly after initiation of antiarrhythmic treatment. An accelerated idioventricular rhythm persisted in 1 horse for at least 8 months and failed to respond to antiarrhythmic drugs. Ventricular premature depolarizations resolved or decreased considerably in frequency in 11 horses without the administration of antiarrhythmic agents. Treatment in these horses included therapy for any underlying systemic disease, corticosteroids, nonsteroidal antiinflammatory drugs, or stall rest. The remaining horse was euthanatized several hours after hospitalization.

Five horses died or were euthanatized either during hospitalization or several months after being discharged. Myocardial lesions were identified at necropsy in 2 horses.

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in Journal of the American Veterinary Medical Association

Summary

Sonographic findings correlated with necropsy findings in 8 of 9 horses in which the cranial portion of the mediastinum was evaluated by use of both methods. Cranial mediastinal masses were imaged as multilobular and homogeneously hypoechoic; a complex echogenic pattern was observed with necrosis within the mass. Pleural effusion was a common finding in horses with mediastinal lymphosarcoma. Cytologic evaluation of pleural fluid samples was useful in diagnosis of lymphosarcoma in 10 of 12 horses that had thoracentesis. Sonographic examination of the thorax and cranial portion of the mediastinum can aid in the diagnosis of mediastinal lymphosarcoma in horses. Such examination should be performed in horses with clinical signs of cranial vena cava obstruction in which pleural effusion is detected, or when thoracic lymphosarcoma is suspected.

Free access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To identify factors significantly associated with an epidemic of fibrinous pericarditis during spring 2001 among horses in central Kentucky.

Design—Case-control study.

Animals—38 horses with fibrinous pericarditis and 30 control horses examined for other reasons.

Procedure—A questionnaire was developed to solicit information regarding a wide range of management practices and environmental exposures from farm owners or managers.

Results—The following factors were found in bivariate analyses to be significantly associated with an increased risk of pericarditis: being from a farm with mares and foals affected by mare reproductive loss syndrome, exposure to Eastern tent caterpillars in or around horse pastures, younger age, shorter duration of residence in Kentucky and at the farm of current residence, being fed hay grown outside Kentucky, a lack of access to pond water, access to orchard grass for grazing, and a lack of direct contact with cattle. In multivariate logistic regression analyses, only variables related to caterpillar exposure and age were significantly associated with fibrinous pericarditis.

Conclusions and Clinical Relevance—Results suggest that fibrinous pericarditis in horses may be associated with mare reproductive loss syndrome. Exposure to Eastern tent caterpillars was the greatest risk factor for development of fibrinous pericarditis. The distribution of times of diagnosis of fibrinous pericarditis was consistent with a point-source epidemic. (J Am Vet Med Assoc 2003;223:832–838)

Full access
in Journal of the American Veterinary Medical Association