JoAnn Slack

Effect of intraperitoneal PERIDAN™ concentrate adhesion reduction device on clinical findings, infection, and tissue healing in an adult horse jejunojejunostomy model.

OBJECTIVE To evaluate the effect of PERIDAN™ Concentrate on clinical findings, infection, and tissue healing in adult horses undergoing celiotomy and jejunojejunostomy. STUDY DESIGN Block randomized blinded experimental in vivo study. ANIMALS Adult horses (n = 12). METHODS Horses had jejunojejunostomy at 2 sites and were administered 5 L of diluted PERIDAN™ Concentrate (6 horses) or Lactated Ringers Injection (LRS) control intraperitoneally (6 horses) before body wall closure. Postoperative monitoring comprised physical examinations, serial hematology, coagulation and chemistry panels, and ultrasonographic examination. Horses were euthanatized 10 days postoperatively. Anastomoses and linea alba incisions were tested for mechanical strength; and tissue healing, inflammation, and infection were assessed by histological evaluation. Data were analyzed using a mixed model ANOVA. Level of significance was P < .05. RESULTS No physical examination differences were observed between groups. Statistically significant differences were observed in leukocyte and neutrophil counts, prothrombin time, antithrombin III activity, intestinal bursting pressures, and histologic healing grade in the mid region of the linea alba. These differences were minimal, and of no observable clinical significance. Other blood variable and histologic differences between groups were not significant. CONCLUSIONS PERIDAN™ Concentrate was safely administered intraperitoneally to healthy horses undergoing celiotomy and anastomosis.

Occurrence of cardiac arrhythmias in Standardbred racehorses

REASONS FOR PERFORMING STUDY Cardiac arrhythmias are a recognised but poorly characterised problem in the Standardbred racehorse. Frequency data could aid the development of cardiac arrhythmia screening programmes. OBJECTIVES To characterise the occurrence of cardiac arrhythmias in Standardbreds prior to racing and in the late post race period using a handheld, noncontinuous recording device. STUDY DESIGN Prospective, observational study, convenience sampling. METHODS Noncontinuous electrocardiographic recordings were obtained over a 12 week period from Standardbred horses competing at a single racetrack. Electrocardiograms were obtained before racing and between 6 and 29 min after the race using a handheld recording device. Prevalence of arrhythmias was calculated for all horses and overall frequency of arrhythmias was calculated for race starts and poor performers. Univariate logistic regression analysis was used to identify risk factors for cardiac arrhythmias. RESULTS A total of 8657 electrocardiogram recordings were obtained from 1816 horses. Six horses had atrial fibrillation after racing (prevalence = 0.11%, frequency = 0.14%), one horse had supraventricular tachycardia before racing (prevalence = 0.06%, frequency = 0.02%), and 2 horses had ventricular tachyarrhythmias after racing (prevalence = 0.06%, frequency = 0.05%). The frequency of atrial fibrillation among race starts with poor performance was 1.3-2.0%. Increasing age was a significant risk factor for the presence of atrial premature contractions before racing and atrial fibrillation and ventricular ectopy after racing. CONCLUSIONS Both physiological and pathological cardiac arrhythmias can be detected in apparently healthy Standardbred horses in the prerace and late post race period using noncontinuous recording methods. Future studies should examine cumulative training or racing hours as a risk factor for cardiac arrhythmia. The prevalence and frequency information may be useful for track veterinarians and regulatory personnel following trends in cardiac arrhythmias.

Hypertensive cardiomyopathy in horses: 5 cases (1995–2011)

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.

Detection of two equine trisomies using SNP-CGH

Chromosomal aberrations in the horse are known to cause congenital abnormalities, embryonic loss, and infertility. While diagnosed mainly by karyotyping and FISH in the horse, the use of SNP array comparative genome hybridization (SNP-CGH) is becoming increasingly common in human diagnostics. Normalized probe intensities and allelic ratios are used to detect changes in copy number genome-wide. Two horses with suspected chromosomal abnormalities and six horses with FISH-confirmed aberrant karyotypes were chosen for genotyping on the Equine SNP50 array. Karyotyping of the first horse indicated mosaicism for an additional small, acrocentric chromosome, although the identity of the chromosome was unclear. The second case displayed a similar phenotype to human disease caused by a gene deletion and so was chosen for SNP-CGH due to the ability to detect changes at higher resolutions than those achieved with conventional karyotyping. The results of SNP-CGH analysis for the six horses with known chromosomal aberrations agreed completely with previous karyotype and FISH analysis. The first undiagnosed case showed a pattern of altered allelic ratios without a noticeable shift in overall intensity for chromosome 27, consistent with a mosaic trisomy. The second case displayed a more drastic change in both values for chromosome 30, consistent with a complete trisomy. These results indicate that SNP-CGH is a viable method for detection of chromosomal aneuploidies in the horse.

Myocardial insult and arrhythmias after acute hemorrhage in horses

OBJECTIVE The objectives of this investigation were to: (1) Determine if acute hemorrhage is associated with increased plasma cardiac troponin I (cTnI) concentration or cardiac arrhythmias, (2) to describe the types of arrhythmias and their clinical course in horses following acute hemorrhage, (3) to determine the ability of clinical or clinicopathological variables to predict an increase in cTnI concentration and the presence of arrhythmias, and (4) to determine the associations of cTnI and cardiac arrhythmias with outcome. DESIGN Prospective observational study. SETTING Large animal veterinary teaching hospital. ANIMALS Eleven client-owned adult horses admitted for treatment of acute hemorrhage (HG) and 4 adult horses undergoing controlled blood collection (BDG). METHODS Serial cTnI concentrations were measured and continuous ECGs were obtained from the HG and BDG groups. Statistical tests were used to determine associations among acute hemorrhage and plasma cTnI concentrations, the presence of cardiac arrhythmias, clinicopathologic data (heart rate [HR], packed cell volume [PCV], total plasma protein [TPP], plasma lactate, and plasma creatinine concentrations), and outcome. RESULTS Plasma cTnI concentration and ECG were within reference intervals at all time points in the BDG. All horses in the HG had increased cTnI (ranging from 0.1-29.9 ng/mL). Arrhythmias were detected in 8 of these horses. There was an association between acute hemorrhage and increased cTnI (P = 0.004, ρ = 0.77), and the presence of arrhythmias (P = 0.026, ρ = 0.64). There were associations among plasma cTnI concentration and the presence of arrhythmias (P = 0.005), arrhythmias requiring treatment (P = 0.036), and poor outcome (P = 0.024). CONCLUSIONS Acute hemorrhage results in myocardial injury that can be detected by measuring cTnI concentration. Arrhythmias were frequent in hospitalized horses following acute hemorrhage.

Transrectal ultrasonographic characterization of the accessory sex glands, pelvic urethra, and ureters in normal geldings.

Transrectal ultrasound of the internal urogenital tract may be used to aid in the diagnosis of reproductive tract and urinary tract pathology in both stallions and geldings. Abnormalities of the accessory sex glands of geldings are uncommon, although prostatic masses have recently been described in adult geldings presenting with dysuria, stranguria, and/or hematuria. The purpose of this study was to describe the normal ultrasonographic features and sizes of the accessory sex glands, caudal ureters, and pelvic urethra in clinically normal geldings. Eleven healthy geldings with no history of urogenital tract pathology were evaluated by a single observer experienced in ultrasound of the stallion accessory sex glands. The ultrasonographic appearance, relative anatomic relationships and sizes of the accessory sex glands, caudal ureters, and pelvic urethra were investigated using both rectal linear array and microconvex array transducers. Summary statistics including mean, standard error, confidence intervals, and range were calculated for each structure. There were no statistically significant differences in measurements between the left and right sides of paired structures or between measurements obtained with different transducers. Fluid was present in the seminal vesicles of 7 of 9 subjects. Midline cysts of the urethra as well as bulbourethral gland and prostatic cysts were identified. The normal reference ranges defined in this study will be useful in the clinical evaluation of geldings with suspected internal urogenital tract pathology.

Evaluation of coagulation and fibrinolysis in horses with atrial fibrillation.

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.

Comparison of water manometry to 2 commercial electronic pressure monitors for central venous pressure measurement in horses

BACKGROUND Central venous pressure (CVP) customarily has been measured in veterinary patients with water manometry. However, many institutions are now using stallside electronic monitors in both anesthesia and intensive care units for many aspects of patient monitoring. HYPOTHESIS Electronic stall side monitoring devices will agree with water manometry for measurement of CVP in horses. ANIMALS Ten healthy adult horses from the university research herd. METHODS Central venous catheters were placed routinely, and measurements were obtained in triplicate with each of the 3 methods every 12 hours for 3 days. Data were analyzed by a Lin concordance correlation coefficient and modified Bland-Altman limits of agreement, with all devices compared pairwise. RESULTS Compared with water manometry, agreement (bias) of the Passport was -1.94 cmH₂O (95% limits of agreement, -8.54 to 4.66 cmH₂O) and of the Medtronic was -1.83 cmH₂O (95% limits of agreement, -8.60 to 4.94 cmH₂O). When compared with the Passport, agreement of the data obtained with the Medtronic was 0.27 cmH₂O (95% limits of agreement, -4.39 to 4.93 cmH₂O). CONCLUSIONS AND CLINICAL IMPORTANCE These data show that both electronic monitors systematically provide measurements that are approximately 2 cmH₂O lower than water manometry, but differences between the 2 electronic devices are small enough (< 0.5 cmH₂O) to be considered clinically unimportant. This discrepancy should be taken into account when interpreting data obtained with these monitoring devices.

Third-Degree Atrioventricular Block and Collapse Associated with Eosinophilic Myocarditis in a Horse

Third‐degree atrioventricular block (AVB) and primary inflammatory myocarditis are uncommon findings in horses. The horse of this report presented for collapse at rest and was found to have multiple cardiac arrhythmias, most notably 3rd‐degree AVB. The horse was subsequently diagnosed with eosinophilic myocarditis on necropsy, a rare form of myocarditis not previously reported in horses. Despite extensive testing, an etiologic agent could not be identified, illustrating the difficulty in identifying a specific cause of myocarditis in horses.