Successful management of minoxidil 5% toxicosis in 2 cats from the same household.

OBJECTIVE: To describe the successful management of 2 cats following ingestion of minoxidil 5%. SERIES SUMMARY: Two 2-year-old neutered male Savannah cats were presented following suspected minoxidil 5% ingestion. Both cats developed significant myocardial injury, and clinical signs were consistent with congestive heart failure, supported by cardiac troponin I concentrations, echocardiogram, and thoracic radiographs. They required vasopressor therapy and were decontaminated with intravenous lipid emulsion therapy. Following decontamination, both cats were successfully discontinued from vasopressor therapy, and their clinical signs resolved within 24 hours. The cats were successfully discharged without long-lasting cardiac compromise. Their echocardiograms and cardiac troponin concentration 7 weeks after discharge were within reference intervals. NEW OR UNIQUE INFORMATION: This is the first detailed report of the successful management of cats following minoxidil 5% ingestion.

A multicenter, retrospective study of cardiac disease in Borzoi dogs.

Borzoi are large, relatively uncommon sighthounds anecdotally reported to suffer from sudden death. This multicenter retrospective cohort study aimed to describe the sample of Borzoi presenting to veterinary cardiologists for evaluation, with records searched from 14 centers across a study period of up to 20 years. The study sample was comprised of 152 client-owned Borzoi, with dogs most commonly presenting for pre-breed screening in 87/152 (52%), followed by evaluation of an arrhythmia in 28/152 (18%). Of the 131/152 (86%) dogs that had an echocardiogram performed, 85/131 (65%) were structurally normal, with 40/85 (47%) structurally normal dogs having trace or mild atrioventricular valve regurgitation. Tricuspid valve dysplasia was the most commonly diagnosed congenital cardiac disease (n = 6). Myxomatous mitral valve disease (n = 12) and dilated cardiomyopathy (n = 13) were diagnosed at similar frequencies, though 92% of valve disease cases were mild. Only 48/152 (32%) Borzoi had a diagnostic electrocardiogram (ECG) and/or a Holter monitor for arrhythmia screening. Despite this, ventricular arrhythmias were identified during the entirety of the available cardiac evaluation including diagnostic ECG, contemporaneous ECG monitoring during the echocardiogram, and/or Holter monitor in 25/131 (19%) dogs in which an echocardiographic diagnosis was available. Of these 25 Borzoi, 76% had minimal or no structural cardiac disease identified, and five had a family history of sudden death. A sudden death outcome was reported in 3/55 (5%) Borzoi with long-term outcome data available. In conclusion, Borzoi commonly have trace or mild atrioventricular valve insufficiencies, and may develop ventricular arrhythmias and dilated cardiomyopathy.

Use of alfaxalone in bearded dragons (Pogona vitticeps): optimizing pharmacodynamics and evaluating cardiogenic effects via echocardiography.

OBJECTIVE: Bearded dragons (Pogona vitticeps), a popular zoological companion species, frequently require sedation for procedures. A novel formulation of alfaxalone with preservatives was FDA approved for 28-day use after the vial is breached. Research has been performed in squamate species using alfaxalone without preservatives at various doses and routes of administration, but it is unknown whether preservatives affect quality of sedation or cardiac function. ANIMALS: 10 bearded dragons. PROCEDURES: This complete crossover study evaluated the pharmacodynamic effects of alfaxalone with preservatives administered to bearded dragons via intracoelomic (ICo; n = 10), SC (10), IM (9), and IV (9) injection at 15 mg/kg. RESULTS: Deep sedation was achieved in 9 of 10 ICo, 8 of 10 SC, 8 of 9 IM, and 9 of 9 IV administrations. Heart rate significantly decreased from baseline for ICo (P = .008; median heart rate, 46), IM (P = .018; 54), and IV (P = .033; 54) routes, but maintained within clinically acceptable limits. Respiratory rate significantly decreased from baseline for ICo (P = .011; median respiratory rate, 30), SC (P = .024; 12), IM (P = .028; 12), and IV (P = .043; 12) routes. Spontaneous ventilation was retained during all events. Time to first effects was significantly sooner with IV (0 min) administration compared with ICo (P = .02; 5 min) and IM (P = .008; 5 min). Time to loss and recovery of withdrawal, righting reflex, deep pain, and purposeful movement were not significantly different between routes of administration. End-systolic volume was the only echocardiographic parameter significantly affected by IV sedation. CLINICAL RELEVANCE: Sedation quality was most consistent via IV administration at 15 mg/kg, and minimal changes in cardiac function were observed.

Canine urinary lactate and cortisol metabolites in hypercortisolism, nonadrenal disease, congestive heart failure, and health.

Spontaneous hypercortisolism (HC) is a common endocrine disease of senior dogs, often overlapping in selected clinical signs and hematologic and blood biochemical abnormalities with nonadrenal diseases (NADs). HC and NAD could differentially affect cortisol metabolism, which is a complex 10-enzymatic pathway process. HC might also affect blood and urine lactate levels through its effects on mitochondrial function. We aimed to differentiate between HC and NAD via a urinary cortisol metabolites and lactate panel. We prospectively recruited 7 healthy dogs and 18 dogs with HC, 15 with congestive heart failure (CHF), and 9 with NAD. We analyzed urine by gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry. We normalized urinary lactate and cortisol metabolites to urine creatinine concentration, and then compared groups using a linear-mixed model and principal component (PC) analysis. A machine-learning classification algorithm generated a decision tree (DT) model for predicting HC. The least-squares means of normalized urinary 6ß-hydroxycortisol and PC1 of the HC and CHF groups were higher than those of the healthy and NAD groups (p = 0.05). Creatinine-normalized urinary 6ß-hydroxycortisol had better sensitivity (Se, 0.78; 95% CI: 0.55-0.91), specificity (Sp, 0.89; 95% CI: 0.57-0.99), and a likelihood ratio (LR; 7), than the Se (0.72; 95% CI: 0.49-0.88), Sp (0.89; 95% CI: 0.57-0.99), and LR (6.5) of PC1 for distinguishing HC from NAD. Lactate and dihydrocortisone had the highest decreasing node-weighted impurity value and were considered the most important features in the DT model; dihydrocortisol had no role in determining whether a dog had HC.

Prognostic Value of Neutrophil-to-Lymphocyte Ratio in Cats With Hypertrophic Cardiomyopathy.

Objective: To assess the prognostic value of neutrophil-to-lymphocyte ratio (NLR) for cardiac death in cats with hypertrophic cardiomyopathy. Study Design: Prospective observation study. Animals: Ninety-six client-owned cats. Methods: Complete blood count samples were collected from 38 healthy and 58 cats with hypertrophic cardiomyopathy (HCM), and the NLR ratios were analyzed. All cats had echocardiographic measurements performed on the same day as blood collection. Spearman rank correlation was used to assess the relationship between echocardiographic measurements and NLR. Long-term outcome data were obtained, and time to cardiac death and variables associated with cardiac death were analyzed using Kaplan-Meier survival curves and Cox proportional hazards models, respectively. Results: The NLR was significantly higher in cats with confirmed congestive heart failure. When evaluating HCM patients, cats in the third NLR tertile had a significantly higher risk of cardiac death with a hazard ratio of 10.26 (95% CI: 1.84-57.14; p = 0.0001) when compared with that of patients in the first tertile. NLR was significantly associated with echocardiographic measures of left atrial size, left auricular function, the presence of left atrial spontaneous echo contrast (SEC), and thrombus formation. Conclusions and Clinical Relevance: Increased NLR is a negative prognostic indicator in cats with HCM.

Multidose pharmacokinetics and safety of a modified, compounded theophylline product in dogs.

Theophylline is used in canine medicine for the management of chronic bronchitis and bradyarrhythmias, yet no species-validated commercial products are available. This study reports the single-dose and multidose pharmacokinetics and safety of a modified, compounded theophylline (MCT) product readily available from a well-established, USP-compliant compounding pharmacy, which may be a suitable and reliable source for theophylline for dogs. Eleven dogs underwent serial plasma theophylline measurement following 10 mg/kg MCT PO. After a 7 days washout, dogs received 10 mg/kg MCT PO q12h and serial plasma theophylline quantification was repeated after the ninth dose. Dogs were monitored for potential adverse effects. For the nine dogs that completed the study, plasma theophylline concentrations were between 5 and 30 µg/ml for 91 +/- 15% of the dosing interval. There was no significant difference in half-life between single-dose and multidose administration. The most common adverse effects reported were mild and included agitation, excitement, and increased activity. The results of this study support the use of 10 mg/kg MCT administered twice daily as a starting dosage in dogs. This regimen appears safe, achieves appropriate plasma drug concentrations in most dogs, and does not cause significant changes in pharmacokinetic properties at steady state. Because compounded drugs do not undergo consistent testing for identity, quality, strength, purity, and stability, results of research described in reports using compounded products may not be reproducible.

Cardiac extracellular volume fraction in cats with preclinical hypertrophic cardiomyopathy.

BACKGROUND: Cardiac magnetic resonance imaging (CMR) allows for detection of fibrosis in hypertrophic cardiomyopathy (HCM) by quantification of the extracellular volume fraction (ECV). HYPOTHESIS/OBJECTIVES: To quantify native T1 mapping and ECV in cats. We hypothesize that native T1 mapping and ECV will be significantly increased in HCM cats compared with healthy cats. ANIMALS: Seventeen healthy and 12 preclinical HCM, age-matched, client-owned cats. METHODS: Prospective observational study. Tests performed included indirect blood pressure, CBC, biochemical analysis including total thyroid, urinalysis, transthoracic echocardiogram, and CMR. Cats were considered healthy if all tests were within normal limits and a diagnosis of HCM was determined by the presence of left ventricular concentric hypertrophy ≥6 mm on echocardiography. RESULTS: There were statistically significant differences in LV mass (healthy = 5.87 g, HCM = 10.3 g, P < .0001), native T1 mapping (healthy = 1122 ms, HCM = 1209 ms, P = .004), and ECV (healthy = 26.0%, HCM = 32.6%, P < .0001). Variables of diastolic function including deceleration time of early diastolic transmitral flow (DTE), ratio between peak velocity of early diastolic transmitral flow and peak velocity of late diastolic transmitral flow (E : A), and peak velocity of late diastolic transmitral flow (A wave) were significantly correlated with ECV (DTE; r = 0.73 P = .007, E : A; r = -0.75 P = .004, A wave; r = 0.76 P = .004). CONCLUSIONS AND CLINICAL IMPORTANCE: Quantitative assessment of cardiac ECV is feasible and can provide additional information not available using echocardiography.

OPTIMIZING THE PHARMACODYNAMICS AND EVALUATING CARDIOGENIC EFFECTS OF THE INJECTABLE ANESTHETIC ALFAXALONE IN PRAIRIE RATTLESNAKES (CROTALUS VIRIDIS).

North American vipers are commonly housed in zoological institutions or studied as free-ranging populations. Because of their venomous predatory and defensive mechanism, sedation or anesthesia is frequently employed to facilitate safe handling and medical procedures, especially of the head. A new formulation of alfaxalone with proprietary preservatives was recently approved and indexed for 28-d use post-vial puncture. Pharmacodynamic effects of alfaxalone in its prior formulation have been researched in nonvenomous species, but the optimal dose and route of administration in vipers have not been reported. In part one, 10 prairie rattlesnakes (Crotalus viridis) participated in a complete four-route crossover study evaluating 20 mg/kg alfaxalone administered intracoelomically (ICo), SC cranial to the heart, IM cranial to the heart, and IV in the ventral coccygeal vein. HR significantly decreased from baseline during IV (P= 0.024), IM (P= 0.024), and SC (P= 0.028) administration. Respiratory rate significantly decreased following alfaxalone delivered IV (P = 0.027). Time to first effects was significantly faster in IV compared with IM (P= 0.01), SC (P= 0.001), and ICo (P= 0.036). All IV and IM administrations resulted in deep sedation, but 70% of the IV and 10% of the IM sedation events resulted in apnea and required intermittent positive ventilation via endotracheal tube. Fifty percent of the ICo sedation events and 10% of the SC sedation events did not result in sedation. One successful SC sedation event resulted in apnea. In part two, echocardiograms were performed in the same rattlesnakes at baseline and at maximum effect of sedation with 20 mg/kg alfaxalone administered IM. Cardiac contractility and output were unaffected. Administration of alfaxalone at 20 mg/kg IM cranial to the heart should facilitate safe handling and minimally invasive procedures in prairie rattlesnakes and related species.

Quantitative assessment of left ventricular volume and function by transthoracic and transesophageal echocardiography, ultrasound velocity dilution, and gated magnetic resonance imaging in healthy foals.

OBJECTIVE: To compare measurements of left ventricular volume and function derived from 2-D transthoracic echocardiography (2DE), transesophageal echocardiography (TEE), and the ultrasound velocity dilution cardiac output method (UDCO) with those derived from cardiac MRI (cMRI) in healthy neonatal foals. ANIMALS: 6 healthy 1-week-old Standardbred foals. PROCEDURES: Foals were anesthetized and underwent 2DE, TEE, and cMRI; UDCO was performed simultaneously with 2DE. Images acquired by 2DE included the right parasternal 4-chamber (R4CH), left apical 4- and 2-chamber (biplane), and right parasternal short-axis M-mode (M-mode) views. The longitudinal 4-chamber view was obtained by TEE. Measurements assessed included left ventricular end-diastolic volume (LVEDV), end-systolic volume (LVESV), ejection fraction, stroke volume (LVSV), cardiac output (CO), and cardiac index (CI). Bland-Altman analyses were used to compare measurements derived from biplane, R4CH, and M-mode images and UDCO with cMRI-derived measurements. Repeatability of measurements calculated by 3 independent reviewers was assessed by the intraclass correlation coefficient. RESULTS: Compared with cMRI, all 2DE and TEE modalities underestimated LVEDV and LVESV and overestimated ejection fraction, CO, and CI. The LVSV was underestimated by the biplane, R4CH, and TEE modalities and overestimated by UDCO and M-mode methods. However, the R4CH-derived LVSV, CO, and CI were clinically comparable to cMRI-derived measures. Repeatability was good to excellent for measures derived from the biplane, R4CH, M-mode, UDCO, and cMRI methods and poor for TEE-derived measures. CONCLUSIONS AND CLINICAL RELEVANCE: All assessed modalities yielded clinically acceptable measurements of LVEDV, LVESV, and function, but those measurements should not be used interchangeably when monitoring patient progress.

Effects of oral trazodone on echocardiographic and hemodynamic variables in healthy cats.

OBJECTIVES: The purpose of this study was to evaluate the effects of oral trazodone on echocardiographic variables, heart rate (HR) and blood pressure (BP) in healthy cats. METHODS: Client-owned domestic cats between 2 and 8 years of age were recruited. Cats were considered healthy based on physical examination, complete blood count, blood chemistry profile, urinalysis, total thyroxine concentration, non-invasive BP measurement by Doppler method and a screening transthoracic echocardiogram with simultaneous electrocardiogram. Echocardiographic variables assessed pre-trazodone and 90-120 mins post-trazodone (50 mg PO) included left ventricular internal diameter in systole and diastole, interventricular septal and left ventricular free-wall thickness in systole and diastole, left atrial size, left auricular function and left ventricular diastolic function assessed by spectral Doppler transmitral and pulmonary venous flow velocities, and tissue Doppler profiles. Mean echocardiographic and hemodynamic variables were calculated for pre- and post-trazodone examinations for each cat. Pre- and post-trazodone variables were analyzed with a paired t-test with significance set at P <0.05. RESULTS: Twelve healthy cats were evaluated. Trazodone was administered to all cats and a sedative effect was observed. There were no clinically significant differences in any echocardiographic variables post-trazodone administration. Systolic BP was significantly decreased after trazodone (P = 0.001) with no significant change in HR. CONCLUSIONS AND RELEVANCE: Trazodone did not alter echocardiographic variables, in a clinically relevant manner, in this group of healthy cats. Trazodone may aid in obtaining transthoracic echocardiograms without affecting HR or echocardiographic variables but may significantly lower BP in healthy cats.