Ashley B. Saunders

Objective: To perform a partial validation of a point-of-care assay (Vcheck cardiac troponin I [VC-cTnI; cTnI]) for measurement of cTnI in canine serum and to perform a method comparison between the VC-cTnI and an established chemiluminescent assay (ADVIA Centaur XP High-Sensitivity Troponin I [AC-cTnI-HS]). Methods: From September 4, 2024, through August 21, 2025, surplus canine serum was collected from a diagnostic laboratory, and within-day variability, dilutional parallelism, spiking recovery, and the effect of common interferents (hemolysis, icterus, and lipemia) were analyzed for the VC-cTnI assay. A method comparison of the VC-cTnI and AC-cTnI-HS assays was performed with 121 canine serum samples. Results: The within-day coefficient of variation ranged from 8.1% to 43.8%, decreasing as cTnI concentrations increased. Dilutional parallelism and spiking recovery assessments had mean ± SD observed-to-expected ratios of 80.5 ± 33.2% (range, 21.1% to 122.2%) and 112.8 ± 35.6% (range, 46.0% to 173.9%), respectively. There was no interference from icterus, hemolysis, or lipemia. There was a positive correlation between the VC-cTnI and AC-cTnI-HS assays (Spearman ρ, 0.742), though 16 of 121 samples (13.2%) were below the VC-cTnI detectable limit. Conclusions: The VC-cTnI assay lacked precision for measurement of concentrations below 0.2 ng/mL, but within-day variability was acceptable for higher concentrations. Clinical Relevance: The VC-cTnI assay is more precise when measuring higher cTnI concentrations and can detect myocardial injury in dogs. Results in the normal and equivocal range of the manufacturer’s reference interval may be more challenging to interpret because of suboptimal precision in this range.

Objective: To describe cardiovascular intra-anesthetic complications and ultrasensitive serum cardiac troponin I (cTnI) concentrations in dogs anesthetized repeatedly for radiation therapy (RT). Animals: 12 client-owned dogs anesthetized once daily (Monday through Friday) for 10 to 20 sessions, totaling 218 general anesthesia (GA) episodes. Clinical Presentation: American Society of Anesthesiologists III sevoflurane-anesthetized dogs (median age, 10 years [range, 2 to 11]; body weight, 27.5 kg [range, 6.0 to 42.3]) undergoing RT. Results: Comparing the first 5 to the last 5 GA episodes, the incidence of bradycardia (heart rate [HR] < 60 beats/min) decreased from 58.3% to 43.8%, hypotension (mean arterial pressure [MAP] < 60 mm Hg) from 28.3% to 16.3%, and hypertension (MAP > 120 mm Hg) from 20.0% to 9.4%. Tachycardia (HR > 160 beats/min [10%]) and ventricular arrhythmias (2.3%) remained infrequent. Fluid bolus administration increased from 5.0% to 20.8%; anticholinergics and inotropes decreased from 35.0% to 15.0%. Median (range) cTnI concentrations were (ng/mL) 0.073 (0.007 to 0.685) at baseline and 0.083 (0.006 to 0.685), 0.073 (0.018 to 0.286), 0.062 (0.010 to 0.265), and 0.033 (0.026 to 0.121) after 5, 10, 15, and 20 GA episodes, respectively. Two dogs had transient elevations after 5 GA episodes (0.132 and 0.500 ng/mL), which normalized; 3 had elevated baseline cTnI (0.135 to 0.685 ng/mL), which decreased during RT; 1 had cardiac disease. Clinical Relevance: With cardiovascular monitoring and timely support, intra-anesthetic complication decreased, and cTnI remained stable or declined with repeated anesthetics. These findings support owner-informed decision-making regarding repeated GA for RT in dogs.

Practical relevance: Cardiomyopathies are a common condition and the leading cause of congestive heart failure (CHF) in cats; however, to date there have been limited therapeutic options available. Commonly used therapeutics include diuretics for CHF and antithrombotics 2 to reduce the risk of arterial thromboembolism (ATE), which do not directly affect myocardial function. This review summarizes the evidence for the use of pimobendan, a phosphodiesterase III inhibitor and calcium channel sensitizer, in feline cardiomyopathies. Potential benefits of pimobendan in cats include improved left ventricular systolic and diastolic function, reduced platelet aggregation, reduction in left atrial size, and improved left atrial and auricular systolic function. Drug details: Pimobendan is indicated for the treatment of CHF in conditions associated with systolic dysfunction (including dilated cardiomyopathy, restrictive cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy and some cases with non-specific phenotypes) and has been used in the treatment of CHF secondary to hypertrophic cardiomyopathy. A dosage of pimobendan of 0.25 mg/kg PO q12h is generally well tolerated, and an approved oral solution is now available in the UK, EU, USA, Japan and Australia, which may facilitate administration in some cats; it should be noted, however, that pimobendan is not licensed for use in cats and marketing authorizations may vary between countries. Adverse events are uncommon with pimobendan but include gastrointestinal upset (anorexia, vomiting), transient changes in heart rate and possible worsening arrhythmias at higher doses. The use of pimobendan is contraindicated in cats with fixed obstructions of the left or right ventricular outflow tract (ie, congenital heart disease – pulmonic or aortic valvular stenosis). Audience: This article reviews the use of pimobendan in cats for primary care veterinarians and includes practical case examples that reflect the typical use and recommendations for usage of pimobendan by the authors.

OBJECTIVE: To describe associations between cardiac abnormalities and Trypanosoma cruzi serostatus by use of a simplified diagnostic evaluation in dogs at risk for T cruzi infection. METHODS: A prospective, cross-sectional study was performed using a simplified diagnostic evaluation including high-sensitivity cardiac troponin I, 30-second ECG, and echocardiogram with 7 variables in 46 client-owned dogs from high-risk environments. Dogs were categorized as serologically positive (SP), negative (SN), or discordant (SD) by use of 2 antibody tests. Functional evaluation of cardiac health scores and blood PCR were obtained. RESULTS: Dogs were SP (n = 19), SN (17), and SD (10), with 9 PCR positive (7 SP, 1 SN, 1 SD). Troponin was above reference range in 6 of 46 (4 SP, 1 SN, 1 SD), and functional evaluation of cardiac health scores were 0 in all dogs. Conduction system abnormalities (prolonged interval durations, second-degree atrioventricular block, splintered QRS complex) and ventricular arrhythmias were documented in 8 (7 SP, 0 SN, 1 SD). Twenty-six (12 SP, 8 SN, 6 SD) had echocardiographic abnormalities, most often myxomatous mitral valve disease (MMVD) and left ventricular enlargement. Seropositive dogs were significantly older and had a higher likelihood of MMVD. Conduction system abnormalities were associated with positive serostatus. CONCLUSIONS: Echocardiographic abnormalities were complicated by MMVD and did not distinguish between serostatus. An ECG with assessment and detailed measurement of complexes and cardiac troponin I are simple tests to perform with abnormalities detected in seroreactive dogs. CLINICAL RELEVANCE: Electrocardiographic abnormalities in high-risk or seroreactive dogs should prompt further evaluation and monitoring of T cruzi infection.

The prevalence of anatomical‐based subtypes of feline congenital extrahepatic portosystemic shunts (EHPSS) has not been completely elucidated. The goal of this study was to use CT angiography to create an anatomical‐based nomenclature system for feline congenital EHPSS. Additionally, subjective portal perfusion scores were generated to determine if intrinsic portal vein development was associated with different shunt conformations or patient age at the time of CT. The SVSTS and VIRIES list services were used to recruit cases. Data collected included patient DOB, gender, breed, weight, CT date, and reported diagnosis. Shunts were classified based upon (1) the shunt portal vessel(s) of origin, (2) the shunt systemic vessel(s) of insertion, and (3) any substantial portal vessels contributing to the shunt. Additionally, hepatic portal perfusion was subjectively scored between 1 (poor/none) and 5 (good/normal) based on the caliber of the intrahepatic PVs. A total of 264 CT scans were submitted from 29 institutions. Due to exclusion criteria, 33 (13%) were removed, leaving 231 CT scans to be included. Twenty‐five different EHPSS anatomies were identified with five classifications accounting for 78% of all shunts (LGP [53%], LGC‐post [11%], LCG [7%], LGC‐pre [4%], and PC [4%]). Shunt origin involved the left gastric vein in 75% of the described classifications. Significant differences were identified among the five most common shunt types with respect to age at the time of CT scan (P = .002), breed (P < .001), and subjective portal perfusion score (P < .001). This refined anatomical classification system for feline EHPSS may enable improved understanding, treatment comparisons, and outcome prediction for cats with these anomalies.

Trypanosoma cruzi infection in dogs can cause heart failure and sudden death with few treatment options available. A litter of 4 dogs living in a T cruzi endemic area were randomized to prophylaxis and nonprophylaxis groups as part of a study evaluating a modified benznidazole dosing regimen administered twice weekly to prevent T cruzi infection during a vector transmission season. The 2 dogs that received prophylaxis remained healthy without T cruzi infection or cardiac disease for >2 years. One dog that did not receive prophylaxis died unexpectedly with acute T cruzi–induced pancarditis, and the second dog tested positive for T cruzi and developed complex arrhythmias with markedly increased cardiac troponin I and improved with a higher benznidazole treatment dose. Although the small sample size precludes definitive conclusions, we describe the potential clinical benefit of prophylactic and early treatment with modified benznidazole dosing regimens for dogs with T cruzi infection.