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Simple Summary: Cardiac troponin-I (cTnI) in plasma is used daily as a biomarker indicative of the severity of myocardial damage in humans suffering cardiac ischemia due to coronary artery disease, commonly referred to as "heart attacks". Because troponin is so similar in humans and domestic animal species, human immunoassays are often used to measure cTnI concentrations in domestic animals. All assays should, however, have normal reference ranges specific to the type of assay and the species of concern. We used a human chemiluminescence assay to measure cTnI concentrations in normal ponies, to establish an assay-specific reference range, and in adult horses with clinical cardiac disease confirmed by electrocardiography and ultrasonography. Horses with atrial fibrillation sometimes had mild increases in cTnI, with concentrations outside the reference range. Horses with ventricular arrhythmias had a 10-fold higher median cTnI than horses with atrial fibrillation, confirming the utility of cTnI plasma measurements in horses with suspected ventricular premature contractions or ventricular tachycardia. Ventricular arrhythmias carry a poorer prognosis for survival than atrial fibrillation in horses. Cardiac troponin-I (cTnI) is a highly sensitive and specific marker of myocardial injury detectable in plasma by immunoassay techniques. Inclusion criteria over a 3-year period required a diagnosis of cardiac disease accompanied by electrocardiographic (ECG) and cardiac ultrasound examinations (n = 23) in adult horses (≥2 years of age). A second group of normal adult ponies (n = 12) was studied as a reference group. Heparinized jugular venous blood samples were collected and centrifuged within 30 min, and the plasma was separated and frozen at −70 °C for subsequent batched cTnI analysis. The lower limit of detection was 0.01 ng/mL, and the upper limit was 100 ng/mL of plasma. Normal equine plasma cTnI concentrations ranged from 0.01 to 0.03 ng/mL (n = 12). Horses with non-arrhythmogenic murmurs (n = 4) included tricuspid (0.05 ng/mL cTnI), mitral (0.07), and aortic insufficiencies (0.01, 0.02). Horses with benign atrial fibrillation (n = 8) had a cTnI range of <0.01–0.09 ng/mL, with four horses having cTnI concentrations falling slightly outside the reference range (0.04, 0.05, 0.06, and 0.09). Horses with ventricular arrhythmias (ventricular premature contractions or ventricular tachycardia) and documentable myocardial toxicities or immunological reactions (n = 5) had cTnI concentrations of 0.05, 0.21, 0.31, 15.18, and >100 ng/mL. Horses with ventricular arrhythmias but no documentation of myocardial toxicity (n = 3) had cTnI concentrations of 0.34, 0.46, and 80.42 ng/mL. When grouped by arrhythmia type and compared using the Mann–Whitney Rank Sum Test, the median ventricular arrhythmia cTnI (0.40 ng/mL) was significantly higher than the median atrial fibrillation cTnI (0.04 ng/mL, p < 0.001). It was concluded that horses with myocardial toxicities and ventricular arrhythmias often had severe elevations in plasma cTnI. [ABSTRACT FROM AUTHOR]

Background: This study aimed to describe and compare therapeutic approaches for horses with acute diarrhea in different geographic regions worldwide. Methods: Clinical information was retrospectively collected from diarrheic horses presented to participating institutions between 2016 and 2020, including fluid therapy on admission, antimicrobial drugs, probiotics, anti-endotoxic medications, anti-inflammatory drugs, gastroprotectants, digital cryotherapy, and toxin-binding agents. Seasonal and geographic differences were investigated. Results: 1438 horses from 26 participating hospitals from 5 continents were included. On admission, 65% (926/1419) of horses were administered a fluid bolus. Antimicrobial drugs were administered to 55% (792/1419) within the first 24 hours of admission, with penicillin and gentamicin being the most used combination (25%, 198/792). Horses with leukopenia (OR: 2.264, 95%CI: 1.754 to 2.921; P<0.001) or meeting systemic inflammatory response syndrome criteria (OR: 2.542, 95%CI: 1.919 to 3.368; P<0.001) had higher odds of being administered antimicrobial drugs. Other treatments administered included probiotics (15%, 215/1438), polymyxin B (13%; 187/1438), pentoxifylline (8%; 118/1438), gastroprotectants (44%; 626/1419), digital cryotherapy (34%; 489/1435), plasma transfusion (13%; 182/1410) and toxin-binding agents (36%; 515/1438). Limitations: Due to the retrospective nature of the study, the rationale for treatment decisions was unavailable, and associations with survival could not be evaluated. Conclusions: Treatments varied between hospitals from different geographic regions. Prospective clinical trials are required to evaluate the effects of various treatments on survival. [ABSTRACT FROM AUTHOR]