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- Author or Editor: Virginia B. Reef x
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Abstract
OBJECTIVE To evaluate horses with atrial fibrillation for hypercoagulability; plasma D-dimer concentrations, as a marker of a procoagulant state; and a relationship between coagulation profile results and duration of atrial fibrillation or presence of structural heart disease.
DESIGN Case-control study.
ANIMALS Plasma samples from 42 horses (25 with atrial fibrillation and 17 without cardiovascular or systemic disease [control group]).
PROCEDURES Results of hematologic tests (ie, plasma fibrinogen and D-dimer concentrations, prothrombin and activated partial thromboplastin times, and antithrombin activity) in horses were recorded to assess coagulation and fibrinolysis. Historical and clinical variables, as associated with a hypercoagulable state in other species, were also recorded.
RESULTS Horses with atrial fibrillation and control horses lacked clinical signs of hypercoagulation or thromboembolism. Compared with control horses, horses with atrial fibrillation had significantly lower antithrombin activity. No significant differences in plasma fibrinogen and D-dimer concentrations and prothrombin and activated partial thromboplastin times existed between horse groups. In horses with atrial fibrillation versus control horses, a significantly larger proportion had an abnormal plasma D-dimer concentration (10/25 vs 2/17), test results indicative of subclinical activated coagulation (18/25 vs 6/17), or abnormal coagulation test results (25/121 vs 7/85), respectively.
CONCLUSIONS AND CLINICAL RELEVANCE Horses with atrial fibrillation did not have clinical evidence of a hypercoagulable state, but a higher proportion of horses with atrial fibrillation, compared with control horses, did have subclinical activated coagulation on the basis of standard coagulation test results.
Abstract
Objective—To determine results for horses undergoing a high-speed treadmill examination, including videoendoscopy of the pharynx and larynx before and during exercise, echocardiography before and after exercise, and electrocardiography before, during, and after exercise, because of poor performance.
Design—Retrospective study.
Animals—348 horses.
Results—A definitive diagnosis was obtained for 256 (73.5%) horses. One hundred forty-eight horses had dynamic obstruction of the airway during exercise, 33 had clinically important cardiac arrhythmias alone, 22 had a combination of dynamic airway obstruction and clinically important cardiac arrhythmias, 19 had poor cardiac fractional shortening immediately after exercise, 10 had exertional rhabdomyolyis, 15 had clinically apparent lameness, and 9 had other disorders. Thirtynine of the horses with dynamic obstruction of the airway during exercise had multiple airway abnormalities. Fifty-three horses also had subclinical myopathy.
Conclusion and Clinical Relevance—Results suggest that a complete evaluation, including a highspeed treadmill examination, should be conducted in horses with poor performance, regardless or whether horses do or do not have a history of abnormal respiratory noises and particularly if the horses have grade- II or -III left laryngeal hemiplegia. (J Am Vet Med Assoc 2000;216:554–558)
Abstract
Objective—To describe the prognosis and clinical, echocardiographic, and pathological features of hypertensive cardiomyopathy in horses.
Design—Retrospective case series.
Animals—5 horses with cardiac hypertrophy and systemic hypertension.
Procedures—Demographics, history, physical and cardiological examination findings, diagnosis, clinical progression, prognosis, and pathological findings were obtained from medical records.
Results—The primary diagnosis was chronic laminitis in 3 horses and chronic renal failure in 2. Persistent tachycardia, hypertension, chronic laminitis, or a combination of these prompted the cardiac evaluations. Blood pressure values (median [range]), measured noninvasively, were determined as 190 mm Hg (183 to 261 mm Hg) for systolic pressure, 126 mm Hg (100 to 190 mm Hg) for diastolic pressure, and 155 mm Hg (126 to 222 mm Hg) for mean pressure. No arrhythmias were reported. For the left ventricle, all horses had increased relative wall thickness, mean wall thickness, and ventricular mass. The interventricular septum was thickened at end diastole (n = 5) and in peak systole (4). The left ventricular internal diameter was small at end diastole (n = 4) and in peak systole (3). The left ventricular free wall was thickened at end diastole (n = 3) and in peak systole (4). No associations between blood pressure and variables consistent with hypertrophy were detected. All horses were euthanized because of the grave prognosis of the primary diseases. All 3 horses that underwent postmortem evaluation had cardiovascular abnormalities.
Conclusions and Clinical Relevance—Hypertensive cardiomyopathy should be considered as a comorbid diagnosis in horses with laminitis or chronic renal failure. Information about the development, progression, reversibility, importance of early detection, and long-term sequelae of this condition is needed.
Abstract
Objective—To determine prevalence of myocardial injury in horses with colic on the basis of high concentrations of cardiac troponin I (cTnI), frequency of cardiac arrhythmias within the first 24 to 48 hours after hospital admission or surgery because of colic, and associations between high cTnI concentrations and cardiac arrhythmias, clinical course, and outcome (survival to discharge from hospital vs nonsurvival [death or euthanasia]).
Design—Prospective observational study.
Animals—111 horses with colic.
Procedures—Blood was drawn at admission and 12 and 24 hours after admission if horses were treated medically or 12 and 24 hours after surgery if treated surgically. A 24-hour ambulatory ECG was recorded beginning the morning after admission in medically treated cases or after surgery and evaluated for arrhythmias. Clinical and clinicopathologic data and outcome were obtained. Associations between cTnI concentrations and other variables were determined.
Results—An abnormal cTnI concentration (≥ 0.10 ng/mL) at admission was significantly associated with the occurrence of ventricular arrhythmias, outcome, and surgical treatment.
Conclusions and Clinical Relevance—The data suggested that horses with colic and high cTnI concentrations at admission were more likely to have ventricular arrhythmias and have a less favorable prognosis for recovery. High cTnI concentrations in horses with colic were suggestive of myocardial damage.
Abstract
Objective—To determine whether there are important differences relating to seasonality of signs or clinical features between subtypes of inflammatory airway disease (IAD) in horses caused by neutrophilic and eosinophilic-mastocytic inflammation having dissimilar etiopathologic pathways.
Design—Retrospective case series.
Animals—98 horses.
Procedures—Data were compiled from medical records of horses examined because of poor performance from 2004 through 2010. Horses underwent a standardized high-speed treadmill test, lameness evaluation, cardiac evaluation, and postexercise bronchoalveolar lavage (BAL). By means of standard BAL cytologic criteria, horses were divided into 4 groups: eosinophilic-mastocytic inflammation, neutrophilia only, mixed inflammation, or no inflammation (control). Associations between IAD subtype and clinical parameters were investigated.
Results—Data for 98 horses were obtained, including age, career, season of admission, and results of hematologic evaluation, high-speed treadmill arterial blood gas analysis, upper airway endoscopy, cardiologic evaluation, and BAL. Cytologic evidence of IAD was found in 81% (79/98) of the horses, and 30% (30/98) had erythrocytes present in the BAL fluid after exercise. Horses in the eosinophilic-mastocytic inflammation and mixed-inflammation groups were significantly more likely to be Thoroughbred than Standardbred and have larger amounts of mucus in their BAL fluid. No significant differences were found in season of evaluation, results of exercising blood gas analyses, or comorbidities.
Conclusions and Clinical Relevance—No association between season and cytologic profile of BAL fluid and no major effects of IAD subtype on pulmonary gas exchange during exercise were seen in this population of horses.
