BACKGROUND:Vertebral heart size (VHS) and vertebral left atrial size (VLAS) are objective radiographic measurements of heart and left atrial size, respectively and are associated with inter- and intraobserver variability when measured by humans. Artificial intelligence (AI) tools to determine VHS and VLAS have been developed and may reduce variability and save time. OBJECTIVES:To compare two manual methods for measuring VHS and VLAS on right and left lateral canine thoracic radiographs and to compare measurements of VHS and VLAS made by deep learning-enabled program, MetronMind, with those made by a trained observer on right and left lateral radiographs. ANIMALS:Client-owned dogs (n = 1058) including 80 breeds with a variety of heart sizes, thoracic conformations and radiographic quality. METHODS:Retrospective, single-center, method-comparison study. Pearson's correlation, Bland-Altman plots and Passing-Bablok regression were used to assess agreement. RESULTS:Correlation between traditional and modified manual measurements for VHS and VLAS was strong (r = 0.994 and r = 0.974, respectively), with minimal bias (-0.10 and 0.04 vertebrae, respectively) indicating that the modified methods closely approximate traditional measurements obtained from right lateral views. MetronMind measurements of VHS and VLAS from right lateral radiographs also correlated well with the human observer's modified measurements (r = 0.947 and r = 0.811 respectively), showing small mean biases (0.08 and 0.07 vertebrae, respectively). Correlation between left and right lateral radiographic measurements of VHS (0.87 and 0.91) was higher than for VLAS (0.73 and 0.64) and bias was larger for VHS (0.26 and 0.31 vertebrae) than for VLAS (-0.13 and -0.10 vertebrae) for humans and MetronMind, respectively.

Cardiac troponin I (cTnI) is a cardiac specific biomarker of myocardial damage in humans, dogs, and cats. The ADVIA Centaur XP High-Sensitivity Troponin I assay (AC-cTnI-HS) has been validated for use in humans and dogs, but not for use in cats. The study objective was to analytically validate the AC-cTnI-HS assay for use in cats and to evaluate cTnI measurements in healthy cats compared to those with cardiac disease to assess the clinical utility of this assay. Surplus serum samples from cats were used for analytical validation. Intra- and inter-assay variability, dilutional parallelism, and spiking recovery were assessed. Serum samples from 106 client-owned cats were evaluated. This group was comprised of 51 clinically healthy cats (structurally normal echocardiogram, normal systemic blood pressure, and unremarkable complete blood count and biochemistry profile), 25 cats with stage B1 hypertrophic cardiomyopathy, 7 with stage B2 hypertrophic cardiomyopathy, 7 with stage C cardiomyopathy of any type, 8 with congenital heart disease, and 8 cats with transient myocardial thickening and/or suspected to have myocarditis. Inter-assay and intra-assay coefficients of variation were between 2.7-8.3% and 1.5-4.0%, respectively. The mean ± standard deviation observed to expected ratios for dilutional parallelism and spiking recovery were 124.3 ± 42.8% and 92.9 ± 6.2%, respectively. Healthy cats had significantly lower cTnI concentrations than cats with hypertrophic cardiomyopathy stage B1 (P = 0.012), stage B2 (P = 0.004), or any cardiomyopathy ACVIM stage C (P = 0.002). The AC-cTnI-HS assay is precise, reproducible, linear, and accurate for measurement of cTnI concentrations in serum from cats. This study confirms that measurement of serum cTnI holds promise to have clinical utility as it was able to detect differences in serum cTnI concentrations between healthy cats and those with cardiac disease.

Companion dogs are a powerful model for aging research given their morphologic and genetic variability, risk for age-related disease, and habitation of the human environment. In addition, the shorter life expectancy of dogs compared to human beings provides a unique opportunity for an accelerated timeline to test interventions that might extend healthy lifespan. The Test of Rapamycin In Aging Dogs (TRIAD) randomized clinical trial is a parallel-group, double-masked, randomized, placebo-controlled, multicenter trial that will test the ability of rapamycin to prolong lifespan and improve several healthspan metrics in healthy, middle-aged dogs recruited from Dog Aging Project participants. Here, we describe the rationale, design, and goals of the TRIAD randomized clinical trial, the first rigorous test of a pharmacologic intervention against biological aging with lifespan and healthspan metrics as endpoints to be performed outside of the laboratory in any species.

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.

Introduction/objectives: Veterinary echocardiographers' preferences for left atrial (LA) size assessment in dogs have never been systematically investi-gated. The primary aim of this international survey study was to investigate echocardiographers' preferences for LA size assessment in dogs. The secondary aim was to investigate echocardiographers' preferences for assessing LA size in subgroups based on geographic, demographic, and professional profiles. Animals, materials, and methods: An online survey instrument was designed, verified, and distributed globally to the veterinary echocardiographers. Results: A total of 670 echocardiographers from 54 countries on six continents completed the survey. Most echocardiographers (n = 621) used linear two-dimensional (2D)-based methods to assess LA size, 379 used subjective assessment, and 151 used M-mode-based methods. Most commonly, echocardiogra-phers combined linear 2D-based methods with subjective assessment (n = 222), whereas 191 used linear 2D-based methods alone. Most echocardiographers (n = 436) using linear 2D-based methods preferred the right parasternal short-axis view and indexed the LA to the aorta. Approximately 30% (n = 191) of the echocardiographers who performed linear measurements from 2D echocardio-grams shared the same preferences regarding dog position, acquisition view, indexing method, and identification of the time-point used for the measurement. The responses were comparably homogeneous across geographic location, training level, years of performing echocardiography, and type of practice. Discussion/conclusion: Most veterinary echocardiographers assessed LA size in dogs using linear 2D echocardiography from a right parasternal short-axis view, and by indexing the LA to the aorta. The respondents' preferences were similar across geographic, demographic, and professional backgrounds. 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Introduction:Pacemaker implantation is the treatment of choice for clinically relevant bradyarrhythmias. Pacemaker-lead-associated thrombosis (PLAT) occurs in 23.0-45.0% of people with permanent transvenous pacemakers. Serious thromboembolic complications are reported in 0.6-3.5%. The incidence of PLAT in dogs is unknown. Animals, materials and methods: multicenter retrospective study of seven centers with 606 client-owned dogs undergoing permanent pacemaker implantation between 2012 and 2019. 260 dogs with a transvenous pacemaker with echocardiographic follow-up, 268 dogs with a transvenous pacemaker without echocardiographic followup and 78 dogs with an epicardial pacemaker. Results:10.4% (27/260) of dogs with transvenous pacemakers and echocardiographic follow-up had PLAT identified. The median time to diagnosis was 175 days (6-1853 days). Pacemaker-lead-associated thrombosis was an incidental finding in 15/27 (55.6%) dogs. Of dogs with a urine protein:creatinine ratio measured at pacemaker implantation, dogs with PLAT were more likely to have proteinuria at pacemaker implantation vs. dogs without PLAT (6/6 (100.0%) vs. 21/52 (40.4%), P=0.007). Urine protein:creatinine ratio was measured in 12/27 (44.4%) dogs at PLAT diagnosis, with proteinuria identified in 10/12 (83.3%) dogs. Anti-thrombotic drugs were used following the identification of PLAT in 22/27 (81.5%) dogs. The thrombus resolved in 9/15 (60.0%) dogs in which follow-up echocardiography was performed. Dogs with PLAT had shorter survival times from implantation compared to those without PLAT (677 days [9-1988 days] vs. 1105 days [1-2661 days], P=0.003). Conclusions:Pacemaker-lead-associated thrombosis is identified in 10.4% (27/260) of dogs following transvenous pacing, is associated with proteinuria, can cause significant morbidity, and is associated with reduced survival times. & COPY; 2023 Elsevier B.V. All rights reserved.

BackgroundA point-of-care ultrasound (POCUS) protocol for evaluation of the cardiac and respiratory systems in horses does not exist. Objectives(a) Describe the windows of a POCUS protocol for cardiorespiratory assessment of horses (CRASH); (b) Estimate the number of acoustic windows that can be acquired by a sonographer-in-training; (c) Estimate the time required to complete the protocol for specific groups of horses; (d) Describe the sonographic abnormalities detected in horses presented with cardiovascular, respiratory, or systemic disease. AnimalsTwenty-seven healthy horses, 14 horses competing in athletic events, and 120 horses with clinical disease. MethodA pocket-sized ultrasound device was used to acquire 7 sonographic cardiorespiratory windows in various clinical scenarios. The duration of the examination was timed, and images were evaluated for diagnostic quality. Abnormalities in horses with clinical disease were determined by an expert sonographer. ResultsThe CRASH protocol could be performed in healthy and diseased horses in hospital, barn, and competition settings between 5.5 +/- 0.9 (athletic horses) and 6.9 +/- 1.9 min (horses with clinical disease). Thoracic windows were obtained most consistently, followed by right parasternal long-axis echocardiographic windows. Frequently detected abnormalities were pleural fluid, lung consolidation, B-lines, and moderate-to-severe left-sided heart disease. ConclusionsThe CRASH protocol was feasible using a pocket-sized ultrasound device in various groups of horses, could be completed rapidly in a variety of settings, and frequently identified sonographic abnormalities when evaluated by an expert sonographer. The diagnostic accuracy, observer agreement, and utility of the CRASH protocol merit further evaluation.

Cardiac troponin I (cTnI) is considered the gold standard biomarker for myocardial injury and shows a high degree of homology between humans and dogs. The ADVIA Centaur XP High-Sensitivity Troponin I (AC-cTnI-HS) assay has been validated for use in humans but not dogs. The study objectives were to analytically validate the AC-cTnI-HS assay in dogs, to assess correlation between the AC-cTnI-HS and a previous ADVIA Centaur TnI-Ultra (AC-cTnI-U) assay, to assess cTnI sample storage stability, and to clinically evaluate the AC-cTnI-HS assay in healthy dogs and dogs with cardiac disease. Canine serum samples were used for analytical validation. Intra- and inter-assay variability, dilutional parallelism, and spiking recovery were assessed. Samples from 196 client-owned dogs were evaluated (healthy dogs (n = 39) or dogs with congenital heart disease (n = 54), myxomatous mitral valve disease (n = 68), dilated cardiomyopathy (n = 15), or myocarditis (n = 20)). Inter- and intra-assay coefficient of variation (%CV) was between 2.8–41.4% and 3.8–30.2%, respectively, with pools with concentrations >20 pg/mL all having %CVs <10%. The observed to expected ratios for dilutional parallelism and spiking recovery experiments ranged between 92.3 and 266.7.0% and 84.3 and 108%, respectively. A strong correlation between the AC-cTnI-HS and AC-cTnI-U assays was observed (Spearman’s ρ = 0.927), though a proportional bias existed, with AC-cTnI-HS assay concentrations being proportionally lower than AC-cTnI-U assay concentrations. Serum samples stored at -80°C had stable cTnI measurements for up to 2.7 years and after a single freeze-thaw cycle. Healthy dogs and dogs with congenital heart disease had significantly lower cTnI concentrations than dogs in the other three groups. The AC-cTnI-HS assay precisely, reproducibly, and accurately measures cTnI concentrations in dog serum with cTnI concentrations >20 pg/mL.

Introduction:Geroscience studies of low-dose rapamycin in laboratory species have identified numerous benefits, including reversing age-related cardiac dysfunction. Cardiovascular benefits have been observed in dogs with 10 weeks of treatment, raising questions about possible benefits and adverse effects of long-term use of low-dose rapamycin. The objectives of this study were to assess the impact of 6 months of low-dose rapamycin on echocardiographic indices of cardiac function in healthy dogs and to document the occurrence of adverse events.Methods:Seventeen client-owned dogs aged 6–10 years, weighing 18–36 kg, and without significant systemic disease were included in a prospective, randomized, placebo-controlled, masked clinical trial. Low-dose rapamycin (0.025 mg/kg) or placebo was administered three times per week for 6 months. Baseline, 6-month, and 12-month evaluation included physical examination, cardiology examination, and clinicopathology. Three-month evaluation included physical examination and clinicopathology. Owners completed online questionnaires every 2 weeks.Results:There were no statistically significant differences in echocardiographic parameters between rapamycin and placebo groups at 6 or 12 months. No clinically significant adverse events occurred. In 26.8% of the bi-weekly surveys owners whose dogs received rapamycin reported perceived positive changes in behavior or health, compared to 8.1% in the placebo group (p = 0.04).Discussion:While no clinically significant change in cardiac function was observed in dogs treated with low-dose rapamycin, the drug was well-tolerated with no significant adverse events.

Introduction:Cavalier King Charles Spaniels (CKCS) are predisposed to developing myxomatous mitral valve disease (MMVD). Dogs with stage B2 MMVD benefit from medication.Objectives: To develop (1) breed-specific cut-offs for individual screening tests and (2) predictive models utilizing physical examination (PE), ECG, radiograph, and blood-based biomarker variables in combination for identification of echocardiographic stage B2 MMVD in preclinical CKCS.Animals: Adult, preclinical CKCS not receiving cardiac medications (N = 226).Materials and methods: Prospective, cross-sectional study. Enrolled CKCS underwent PE, ECG, radiography, Doppler blood pressure measurement, echocardiography, and biomarker testing. Dogs were grouped by MMVD stage using echocardiography only. The discriminatory ability of individual tests to identify stage B2 was assessed, and prediction models were developed using variables derived from four 'tests' (PE, ECG, radiography, and biomarkers).Results: N-terminal pro-B-type natriuretic peptide (NT-proBNP) and radiographic vertebral heart size (VHS) had the best discriminatory ability of individual diagnostic tests to differentiate stage A/B1 CKCS from stage B2, with an area under the curve (AUC) of 0.855 and 0.843, respectively. An NT-proBNP >= 1138 pmol/L or a VHS >= 11.5 had high specificity for predicting stage B2 (90.1% and 90.6%, respectively). Prediction models incorporating variables from multiple tests had better discriminatory ability than single tests. The four-test prediction model had an AUC of 0.971. Three and two-test models had AUCs ranging between 0.925-0.959 and 0.895-0.949, respectively.Conclusions: Both NT-proBNP and VHS have good utility for predicting echocardiographic stage B2 MMVD in CKCS as individual tests. Prediction models incorporating multiple test variables have superior discriminatory ability.(c) 2023 The Authors. Published by Elsevier B.V. This is an open access article underthe CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

A three-year-old, spayed female, Bichon Frise was diagnosed with an anomalous origin of the left coronary artery from the pulmonary artery, a rare congenital coronary artery defect which has only been reported in two other dogs. Echocardiography was initially performed, though the final diagnosis was made with angiography and computed tomography angiography. An extensive network of collateral coronary circulation allowed for communication between the dilated, tortuous right coronary artery, and the anomalous left coronary artery. Though collateral circulation likely prolonged the patient's life, it is suspected that coronary steal phenomenon and chronic myocardial ischemia ultimately led to fatal ventricular arrhythmias. The dog died suddenly at the age of six, three years after initial diagnosis.

Degenerative valve disease (DVD) is the leading cause of heart disease and congestive heart failure (CHF) in the dog. The first published consensus statement provided guidelines for the diagnosis and treatment of DVD. Although treatment was not recommended in stage B1 DVD, consensus was not reached regarding evidence-based recommendations for treatment of stage B2 DVD. This article addresses the impact of new evidence on historical recommendations for stage B DVD and gives the reader a glimpse into possible future therapies. Management of common sequelae of DVD that can result in clinical signs that are not attributable to CHF is also discussed. anatomy and physiology and highlights numerous indices of RV function assessment for dogs and cats. Imaging techniques, advantages and disadvantages, and clinical impact of these indices are discussed. biomarkers can be measured as an initial screening test; echocardiography is indicated in cats with plasma NT-probrain natriuretic peptide concentra-tions exceeding 100 pmol/L. High-risk cats should be with clopidogrel to reduce the risk of ATE. for controlling signs of CHF; and recommendations for follow-up evalua-tions, monitoring, and troubleshooting. Feline cardiogenic arterial thromboembolism (CATE) is a devastating disease whereby 33% of cats survive their initial event, although approxi-mately 50% of mortality is from euthanasia. Short-term management focuses on inducing a hypocoagulable state, improving blood flow, and providing supportive care. Ideally, all cats should be given 72 hours of treatment to determine the acute clinical course. Preventive protocols include antiplatelet and/or anticoagulant drugs, with the only prospective clinical trial demonstrating that clopidogrel is superior to aspirin with a lower CATE recurrence rate and longer time to recurrent CATE. Newer anticoagulant drugs hold great promise in the future of managing this disease. The of patients is likely to improve ability at the cellular level, an alternate gene delivery approach is to alter myocardial protein levels to improve function. This article discusses background information on gene delivery, including packaging, administration, and a brief discussion of some of the candidate transgenes likely to alter the pro-gression of naturally occurring heart disease in dogs and cats.

Introduction/objectives: Minimal information exists regarding epicar-dial pacemaker (EP) implantation in pet ferrets (Mustela putorius furo). The objec-tives were to describe the indications, surgical technique, and outcome of EP implantation in ferrets for the treatment of advanced atrioventricular block (AVB). Animals, materials, and methods: Eight client-owned ferrets presenting to five ve-terinary referral centers. Signalment, physical exam findings, diagnostic tests, an-esthesia protocols, surgical implantation techniques, postoperative treatment plans, and EP interrogations were reviewed. Intra-and postoperative, minor and major, and EP-related complications were established. Descriptive statistics were performed to report complication rates. Survival analyses were performed.

Four adult dogs weighing <10 kg presented for the evaluation of severe mitral valve stenosis with clinical signs. Owing to the size of the dogs, a hybrid surgical and interventional approach was utilized for balloon valvuloplasty. A left lateral thoracotomy was performed to allow direct entry through the left atrial wall. Transesophageal echocardiography was utilized for the entirety of the procedure in all dogs, and fluoroscopy was additionally used in two dogs. One dog had mild to moderate intra-operative bleeding from the left atrial wall during the procedure, but no other intra-operative complications were observed. No dogs developed a clinically relevant amount of worsened mitral regurgitation. Based on mitral leaflet mobility and transmitral flow profiles, there was perceived improvement in all four dogs. One dog died 6 h after extubation due to respiratory arrest. The remaining dogs survived to discharge and had resolution of clinical signs at home and discontinuation of heart failure medications. One dog died of an unknown cause at five months and another developed atrial fibrillation, and the owners elected to euthanize at ten months after the procedure. One dog continues to do well six months after the procedure as of the time of this writing. Hybrid balloon valvuloplasty can be a viable management option for small breed dogs with severe mitral stenosis exhibiting clinical signs, and both transesophageal echocardiography and fluoroscopy can be used intra-operatively to assist in successful procedural outcomes.

INTRODUCTION/OBJECTIVES:Cavalier King Charles spaniels (CKCS) are ideal candidates for longitudinal study of myxomatous mitral valve (MV) disease and stage B1 clinical trials; however, the optimization of MV measurement acquisition and repeatability must be better defined to realize this potential. Additionally, breed-specific reference ranges for CKCS MV measurements are lacking. Study objectives were to assess measurement repeatability and define optimal methods for the longitudinal study of echocardiographic MV anatomy and to define preliminary, two-dimensional echocardiographic reference ranges for MV measurements in CKCS. ANIMALS:Forty CKCS between 10 and 24 months old. MATERIALS AND METHODS:Pre- and post-sedation two-dimensional echocardiographic images optimized for the MV were obtained. The length, width, and area of the anterior and posterior leaflets and the diameter of the MV annulus at end-diastole and end-systole were measured. Measurement repeatability was assessed using % coefficient of variation and repeatability coefficients. RESULTS:Intraoperator repeatability was best for the operator with previous MV measurement experience, with comparable results for the experienced operator measuring the second operator's images, mimicking a core echocardiography laboratory setting. Except for MV annulus diameter at end-systole, sedation had no significant effect on any MV measurements, nor did it impact measurement repeatability. Preliminary, breed-specific reference ranges were defined for the population, with CKCS often noted to have a larger annular diameter at end-systole than end-diastole. CONCLUSIONS:Optimal methods for longitudinal study of the MV in CKCS have been proposed, as have two-dimensional preliminary echocardiographic reference ranges for CKCS MV measurements. The MV annulus in CKCS may differ from other breeds.

AbstractBackgroundN‐terminal pro‐brain natriuretic peptide (NT‐proBNP) is a widely used point‐of‐care (POC) cardiac biomarker in human medicine. Canine NT‐proBNP is used less in veterinary medicine, possibly due to the lack of a POC canine NT‐proBNP assay resulting in temporal delay, increased degradation in transport, and high reported variability in the available assay. A new quantitative POC analyzer allows fast, onsite measurement of NT‐proBNP, minimizing preanalytical error and reducing variability.ObjectiveWe aimed to analytically validate an NT‐proBNP assay (Vcheck) according to American Society of Veterinary Clinical Pathology (ASVCP) and Clinical Laboratory Improvement Amendments (CLIA) specifications.MethodsArchived and prospective plasma and serum samples were collected from male and female, client‐owned dogs of various breeds with cardiac abnormalities (n = 81) and a healthy control population (n = 225). Precision, accuracy, analytical sensitivity, and specificity, and other statistical analyses were performed.ResultsImprecision was considered acceptable with a coefficient of variation ranging from 9% at 4000 pmol/L to 20% at 600 pmol/L. The lower limit of quantitation was 650 pmol/L based on repetitive measures evaluation. Comparison of the Vcheck assay with the Cardiopet NT‐proBNP assay revealed an excellent correlation with minimal bias when preanalytical factors were controlled. Significant degradation of NT‐proBNP occurred when current methods were used at refrigerated and room temperatures, which could change diagnostic and prognostic decision‐making. Age‐partitioned reference intervals have high reference values of 750 pmol/L and 1280 pmol/L for juvenile and adult dogs, respectively.ConclusionsThe Vcheck NT‐ProBNP assay provides analytically acceptable results. Onsite testing can minimize variability related to preanalytical error and provide clinically useful contemporaneous results. Samples should be centrifuged immediately and analyzed within 2 hours of collection.

Introduction: Large breed (LB) dogs develop dilated cardiomyopathy (DCM) and myxomatous mitral valve disease (MMVD). Echocardiography is required for a definitive diagnosis but is not always available. Our objective was to assess the clinical utility of thoracic radiographs alone and in combination with physical examination and electrocardiography findings for the prediction of clinically important DCM or MMVD in LB dogs. Animals: Four hundred fifty-five client-owned dogs >20 kg with concurrent thoracic radiographs and echocardiogram. Materials and methods: Medical records were reviewed and stored thoracic radio-graphs and echocardiographic images were measured to classify dogs as normal heart size (NHS), preclinical DCM, clinical DCM, preclinical MMVD (with cardiome-galy), clinical MMVD, or equivocal. Dogs with preclinical MMVD, without cardiome-galy, were classified as NHS. Vertebral heart size (VHS) and vertebral left atrial size (VLAS) were measured. Receiver operating characteristic curves and prediction models were derived. Results: Prevalence of MMVD (39 .3%) was higher than the prevalence of DCM (24.8%), though most MMVD dogs (67.0%) lacked cardiomegaly and were classified as NHS for analysis. The area under the curve for VHS to discriminate between NHS and clinical DCM/MMVD or preclinical DCM/MMVD was 0.861 and 0.712, respec-tively, while for VLAS, it was 0.891 and 0.722, respectively. Predictive models incor-porating physical examination and electrocardiography findings in addition to VHS/ VLAS increased area under the curve to 0.978 (NHS vs. clinical DCM/MMVD) and 0.829 (NHS vs. preclinical DCM/MMVD). Conclusions: Thoracic radiographs were useful for predicting clinically important DCM or MMVD in LB dogs, with improved discriminatory ability when physical exam-ination abnormalities and arrhythmias were accounted for.@ 2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

OBJECTIVE To determine breed-specific reference intervals for whole blood (WB) and plasma taurine concentrations in adult, overtly healthy Cavalier King Charles Spaniels (CKCSs) and determine whether taurine concentrations differ across preclinical myxomatous mitral valve disease (MMVD) stages or between CKCSs eating diets that meet World Small Animal Veterinary Association (WSAVA) nutritional guidelines versus other diets. ANIMALS 200 privately owned CKCSs. PROCEDURES Clinically healthy adult CKCSs were recruited prospectively. Diet and supplement history was collected. Dogs were staged by echocardiography using MMVD consensus guidelines. Taurine concentrations were measured in deproteinized lithium heparin WB and plasma samples with the postcolumn ninhydrin derivatization method on a dedicated amino acid analyzer. RESULTS There were 12 stage A (6%), 150 stage B1 (75%), and 38 stage B2 (19%) CKCSs. Seventy-eight dogs (39%) were reported by their owners to be eating diets meeting WSAVA nutritional guidelines; 116 (58%) were not. Taurine concentrations in plasma ( P = .444) and WB ( P = .073) were not significantly different across MMVD stages or between CKCSs eating diets meeting WSAVA nutritional guidelines versus other diets ( P = .345 and P = .527, respectively). Reference intervals for WB taurine (152 to 373 µM) and plasma taurine (51 to 217 µM) concentrations in CKCSs were generated. CLINICAL RELEVANCE In CKCSs, taurine concentrations do not differ significantly based on preclinical MMVD stage, nor do they differ significantly based on consumption of a diet that does or does not meet WSAVA nutritional guidelines.

Introduction: Screening to assess likelihood of preclinical dilated cardi-omyopathy (PC-DCM) prior to advanced diagnostic tests in Doberman Pinschers (DP) is desirable. Objective: To investigate the combined value of physical examination (PE), N -term-inal pro B-type natriuretic peptide (NTproBNP) and cardiac troponin I (cTnI) for identifying PC-DCM in DP. Animals, materials and methods: All dogs underwent: PE, echocardiogram, 3-min ECG and cardiac biomarker measurement. Asymptomatic DP specialIntscript were classified based on 3-min ECG and echocardiogram as: No-DCM/MMVD or myxomatous mitral valve disease (MMVD), PC-DCM based on echocardiogram (PC-DCM-Echo), PC-DCM based on arrhythmias with a normal echocardiogram (PC-DCM-ECG), equivocal DCM (EQ-DCM), and MMVD. Receiver operator characteristic curves and prediction models were derived. Results: Heart murmurs and arrhythmias were rare and gallop sounds were absent in No-DCM/MMVD DP. Dogs > four years old and males had higher probabilities of PC-DCM-Echo. Prediction models incorporating PE variables with NTproBNP had an area under the curve (AUC) of 0.940 for distinguishing between PC-DCM-Echo and all other groups, which was similar to the AUC for NTproBNP (0.939) or cTnI (0.932) alone. Discrimination between No-DCM/MMVD and all other groups was simi-lar for NTproBNP (0.781) and cTnI (0.742) as individual tests, however, models com-bining PE variables and NTproBNP increased the AUC to 0.812. An NTproBNP cut-off of >548 pmol/L, was 100% sensitive and 77.3% specific for detecting PC-DCM-Echo. Conclusions: Both NTproBNP and cTnI had good utility as sole tests to discriminate PC-DCM-Echo DP from all others. Models differentiating No-DCM/MMVD DP from all other DP were improved by using PE and NTproBNP together. 2022 Elsevier B.V. All rights reserved.

Selected electrocardiograph (ECG) intervals may be useful when incorporated into prediction models for cardiac risk assessment in dogs. Standard recommendations for ECG acquisition may not be adhered to in practice. Study objectives were to compare duration of P, PR, QRS, QT, and R wave peak time intervals in: (1) lead II ECGs vs. single lead precordial ECGs in conscious dogs; (2) lead II ECGs with electrodes placed in proximal limb (PL) vs. distal limb (DL) positions with dogs in right lateral (RL) recumbency, left lateral (LL) recumbency and standing positions; (3) single lead precordial ECGs from dogs in RL, LL and standing positions; and (4) before and after sedation with butorphanol in lead II ECGs obtained in RL recumbency. All intervals could be measured in all dogs (conscious and sedated) from a RL lead II ECG with both PL and DL electrode positioning. This was reduced to 98% for lead II ECGs with dogs in LL and standing positions. Intervals that were not different regardless of recording device, dog position, electrode limb position or sedation included P, QRS and P + QRS, suggesting that these intervals have the greatest clinical utility across a variety of recording conditions. The main impact of positioning in healthy dogs was the lack of ability to consistently measure all intervals in standing dogs, particularly P wave duration. Further investigation is needed to determine if this is applicable to dogs with cardiac disease.