VERTEBRAL HEART SIZE IN RETIRED RACING GREYHOUNDS

Effect of body condition score on the interobserver variability of vertebral heart scale assessment in dogs

The vertebral heart scale (VHS) is widely known and used as an objective standard for the evaluation of cardiomegaly on thoracic radiographs. It, therefore, plays an important role in assessing the severity of canine heart disease. The body condition score (BCS) is a nine-scale body condition scoring system used to objectively document the body condition in dogs. Obese animals have widened precardiac and postcardiac mediastinum, fat deposits between the sternum and lungs or heart, as well as increased pericardial fat. These conditions could complicate cardiac silhouette evaluation and could, therefore, result in higher interobserver variability in the assessment of VHS. The purpose of this study was to investigate whether overweight dogs (BCS 6/9, 7/9, 8/9, and 9/9) have more variability in the interobserver VHS measurement compared with dogs with a normal BCS (BCS 4/9 and 5/9). The dogs were admitted to a private referral center for different medical reasons. The VHS was measured by three trained observers in right lateral radiographs of 18 overweight dogs and 33 dogs with a normal BCS. Bland-Altmann plots were constructed, and limits of agreement were calculated to show the variability of VHS measurements. No statistically significant differences in VHS variability were found between BCS categories, observers, sex, or age categories. In conclusion, BCS does not affect the reliability of VHS assessment among trained veterinarians.

The Differences in Radiographic Vertebral Size in Dogs with Different Chest and Skull Types

The objective of this study was to elucidate the differences in vertebral length, vertebral height, and vertebral length/height ratio of the fourth thoracic vertebra (T4), the second lumbar vertebra (L2), the fifth lumbar vertebra (L5) and the seventh lumbar vertebra (L7) based on radiographs in dogs with various body sizes, skull types, and thoracic conformations and to determine the relationships of these parameters with age and sex. A total of 258 dogs were included in this study and classified by three criteria-BW (Criterion 1), skull type (Criterion 2), and thoracic conformation (Criterion 3). Age had weak negative correlations with vertebral length and height. Sex did not affect the vertebral size parameters. BW had strong positive correlations with vertebral length and height, but there was no influence of BW on vertebral length/height ratio. Regarding the different body sizes and conformations, large breeds had vertebrae with significantly greater length and height than small and medium breeds (p < 0.001). In Criterion 2, the vertebrae of the mesocephalic dogs had significantly greater length and height than those of the brachycephalic and dolichocephalic dogs (p < 0.05). In Criterion 3, both deep-chest and round-chest dogs had vertebrae with significantly greater length and height than the barrel-chest dogs (p < 0.0001). Only vertebral length/height ratios of T4 were not influenced by age, sex, BW, skull type, and thoracic conformation. Age, differences in body size, skull type, and thoracic conformation could affect the vertebral size in dogs. Therefore, using breed-specific vertebral lengths and/or heights is a better approach for comparative radiographic analysis with vertebral measurements.

The Thoracic Inlet Length as a Reference Point to Radiographically Assess Cardiac Enlargement in Dogs with Myxomatous Mitral Valve Disease

The diagnostic value of the vertebral heart size (VHS) in dogs with mitral valve degeneration (MVD) is compromised when middle thoracic vertebral anomalies are present. The objective of this study was to assess the use of the thoracic inlet heart score (TIHS) to identify left heart enlargement (LHE) secondary to MVD. The cardiac silhouette of 50 clinically healthy dogs and 106 MVD dogs in different stages was assessed on a right lateral chest radiograph. The TIHS and VHS value were calculated for each patient and compared. The TIHS was significantly different between the control dogs and the dogs with MMVD, increasing with disease stage, control 2.91 ± 0.23, Stage B1 2.98 ± 0.36, B2 3.25 ± 0.34, and C 3.53 ± 0.36, p < 0.05. A THIS ≥3.3 showed 69% sensitivity and 81% specificity to identify LHE. The TIHS showed moderate correlation with the VHS, LA/Ao, and LVIDDN 0.59, 0.42, and 0.62, respectively. The intraobserver and interobserver agreement were almost perfect, 0.96, and substantial, 0.73. The TIHS method can be used to identify LHE secondary to MMVD on dogs' thoracic radiographs.

The Thoracic Inlet Heart Size, a New Approach to Radiographic Cardiac Measurement

In 1995, the Vertebral Heart Size (VHS) method for measuring the cardiac silhouette on thoracic radiographs was published, becoming a quantifiable and objective reference way of assessing the heart size. Since then, many studies have showed that VHS is influenced by breed variations, vertebral malformations, reference points selection, and short and long axes dimensions conversion into vertebral units. The Thoracic Inlet Heart Size (TIHS) normalizes heart size to body size using the thoracic inlet length. The lengths of the long and short axes of the heart of 144 clinically normal dogs were measured on right lateral thoracic radiographs. The sum of both measures was indexed to the thoracic inlet length. For comparison, dogs of the most represented breeds in our hospital were selected to measure their heart size using the TIHS protocol. The mean TIHS value for the population studied was 2.86 ± 0.27, and 90% of dogs had a TIHS value of less than 3.25. There was no difference in TIHS between male and female, and between small and large dogs (p-value < 0.01). There was no difference in the TIHS value between Yorkshire Terrier, Chihuahua, and Labrador retriever breeds, and between each of those three breeds and the general population. The TIHS is a simple, straightforward and accurate way to measure heart size.

Effects of Breed, Exercise, and a Two-Month Training Period on NT-proBNP-Levels in Athletic Dogs

N-terminal pro-b-type natriuretic peptide (NTproBNP) is a cardiac biomarker used to detect myocardial wall stress. Physical activity and cardiac disease can affect serum NTproBNP concentrations. In people, different types of physical activity have different effects on NTproBNP. Our hypothesis was that physical activity and training have an effect on NTproBNP concentrations depending on the type of exercise and the intensity. Seven German Shepherd dogs (GSD) under military training performing short bursts of fast-paced interval exercise and seven Eurohounds (EHs) training for racing competition with endurance exercise were included in the study. Blood samples were taken at enrollment (T₀) and after a two-month (T_2mth) training period; on both occasions, the samples were acquired before and after physical exercise. An echocardiographic evaluation was performed at T₀. Echocardiographic heart size was larger in the EHs compared to the GSDs. The NTproBNP concentration was higher in the EHs than in the GSDs before and after exercise at T₀ and T_2mth. Echocardiographic parameters of heart size and wall thickness correlated with NTproBNP at T₀ before and after exercise. Exercise induced an elevation of NTproBNP in the EHs at T₀ and T_2mth, while in the GSDs this was observed only at T₀. In the EHs, post exercise was associated with higher NTproBNP at T_2mth compared to T₀, while in the GSDs the opposite pattern was noticed. From our study, the serum NTproBNP concentration differs between breeds. Intense physical activity causes an increase in NTproBNP. A two-month training period does not affect the NTproBNP concentration at rest. Intense physical activity may increase NTproBNP above the reference range in individual dogs.

Evaluation of plasma N-terminal pro-B-type natriuretic peptide levels in healthy North American Salukis with normal echocardiographic measurements

Measurement of N‐terminal pro‐B‐type natriuretic peptide (NT-proBNP) levels has been shown to have clinical significance for diagnosis and management of heart disease in dogs. Evaluation of current reference limits for specific breeds is necessary to ensure the test can accurately distinguish between healthy and diseased animals. The objective of this study is to evaluate the adequacy of currently established NT-proBNP reference limits for clinical use in healthy Salukis. Cardiac health of 33 clinically healthy Salukis was evaluated via echocardiography using available breed standards. Plasma concentrations of NT-proBNP were measured using a commercially available assay. A one-sided 97.5% upper reference limit for the NT-proBNP concentrations was calculated using non-parametric percentile method. The 97.5% upper reference limit was 769 pmol/L (90% CI, 547–1214 pmol/L) for the study dogs. This upper reference limit was within the currently established non-breed specific NT-proBNP upper reference limit of 900 pmol/L. No relationship between sex, age, or body weight on plasma levels of NT-proBNP was noted. Results of this study supports the use of currently available non-breed specific NT-proBNP cut-off values for clinical evaluation of healthy Salukis.

Cardiac Radiographic Measurements in Ferrets Using the OsiriX MD Programme

Objectives: To adapt the vertebral heart scale (VHS) for use in ferrets and identify new scales and tools that allow to establish the normal heart size by means of radiography more quickly and effectively.

Methods: Forty healthy pet ferrets (Mustela putorius furo) were used in this prospective study. The measurements were made on right lateral, left lateral, ventrodorsal, and dorsoventral projections, using OsiriX MD medical imaging software, to evaluate sex effect and variance within the different heart scales. Cardiac measurements were also correlated to VHS and the cardiac dimension in the same projection.

Results: Most of the cardiac measurements were significantly different between males and females. The results for the VHS were: right lateral VHS (RL-VHS): 5.52 ± 0.28 v (vertebrae units); left lateral (LL-VHS): 5.55 ± 0.28 v; and dorsoventral VHS (DV-VHS): 6.22 ± 0.34 v for males and RL-VHS: 5.24 ± 0.2 v; LL-VHS: 5.25 ± 0.20 v; and DV-VHS: 5.97 ± 0.35 v for females. Regarding the sternebral heart scale (SHS), the values were: RL-SHS: 5.10 ± 0.20 s (sternebrae units) and LL-SHS: 5.11 ± 0.20 s for males and RL-SHS: 4.67 ± 0.24 s and LL-SHS: 4.67 ± 0.28 s for females. The new measurements based on determining the cardiac area were also marked by clear sexual dimorphism, as shown for the cardiac area-axis (AREA-AXIS): RL-AREA-AXIS: 3.82 ± 0.45 cm²; LL-AREA-AXIS: 3.87 ± 0.41 cm²; ventrodorsal (VD)-AREA-AXIS: 4.59 ± 0.64 cm²; and DV-AREA-AXIS: 4.80 ± 0.50 cm² for males and RL-AREA-AXIS: 2.39 ± 0.23 cm²; LL-AREA-AXIS: 2.41 ± 0.26 cm²; VD-AREA-AXIS: 3.08 ± 0.45 cm²; and DV-AREA-AXIS: 3.06 ± 0.47 cm² for females. The cardiac area open polygon (AREA-POL) values were: RL-AREA-POL: 6.78 ± 0.65 cm²; LL-AREA-POL: 6.88 ± 0.68 cm²; VD-AREA-POL: 7.20 ± 0.91 cm²; and DV-AREA-POL: 7.57 ± 0.88 cm² for males and RL-AREA-POL: 4.28 ± 0.30 cm²; LL-AREA-POL: 4.35 ± 0.35 cm²; VD-AREA-POL: 4.72 ± 0.65 cm²; and DV-AREA-POL: 4.79 ± 0.66 cm² for females, with similar differences noted from various radiographic projections. A good correlation was noted between VHS and SHS, and a very strongly positive correlation existed between cardiac area measurements and cardiac dimensions.

Conclusion: The VHS adapted to ferrets, the SHS, as well as the cardiac area measurements presented in our study are ideal tools for the assessment of cardiac size in ferrets.

Vertebral Heart Scale for the Brittany Spaniel: Breed-Specific Range and Its Correlation with Heart Disease Assessed by Clinical and Echocardiographic Findings

The vertebral heart scale (VHS) was proposed by Buchanan and Bucheler as an objective method for estimating heart size in dogs. However, several studies have reported significant variation between breeds. The purpose of this retrospective study was to evaluate the VHS and to suggest a useful upper limit for normal heart size in Brittany Spaniels. The VHS was measured using a right lateral view in twenty-eight normal dogs and fifteen dogs with myxomatous mitral valve disease. The mean ± SD (standard deviation) VHS was 10.6 ± 0.2 vertebrae (v) in the normal dogs, which differs significantly from the mean VHS of 9.7 ± 0.5 v in Buchanan’s original study with dogs of various breeds. The VHS in the dogs with myxomatous mitral valve disease was 11.9 ± 1.1 v. With a threshold value of 11.1 vertebrae, the sensitivity, specificity, positive and negative predictive values for diagnosing a cardiomegaly are 90%, 72%, 53% and 96%, respectively.

Breed-specific vertebral heart score, vertebral left atrial size, and radiographic left atrial dimension in Cavalier King Charles Spaniels: Reference interval study

Cavalier King Charles Spaniels (CKCS) are predisposed to developing myxomatous mitral valve disease (MMVD), with radiographs frequently used to screen for evidence of left-sided cardiomegaly secondary to MMVD. Vertebral heart size (VHS), vertebral left atrial size (VLAS), modified VLAS (M-VLAS), and radiographic left atrial dimension (RLAD) are reported as objective measurements of global heart size and left atrial size. Normal VHS in CKCS (10.6 ± 0.5) is reportedly higher than the non-breed-specific value (9.7±0.5). Breed-specific VLAS, M-VLAS, and RLAD cut-offs have not been reported in CKCS. The aim of this prospective reference interval study was to describe the VHS, VLAS, M-VLAS, and RLAD values for 30 clinically healthy adult CKCS. Inclusion criteria were unremarkable physical examination, normal echocardiography, and thoracic radiographs without malposition/abnormalities. There were 22 female and eight male dogs. Ages ranged from 1 to 6 years. The VHS mean value in our sample was 10.08 ± 0.56 (95% range, 9.87-10.29). This was significantly greater than a previously published general canine reference value of 9.7 ± 0.5 and significantly less than a previously published CKCS breed-specific value of 10.6 ± 0.5 (P < 0.01). Mean VLAS, M-VLAS, and the RLAD values in our study were 1.79 ± 0.3 (95% range, 1.68-1.9), 2.23 ± 0.44 (95% range, 2.06-2.39), and 1.2 ± 0.34 (95% range, 1.07-1.33), respectively. These were significantly less than previously published reference interval values (P < 0.001). The VHS, M-VLAS, and the RLAD were not affected by sex, body weight, or BCS; whereas the VLAS was moderately affected by body weight. Findings from this study can be used as background for future thoracic radiographic assessments in CKCS.

Vertebral heart size and vertebral left atrial size reference ranges in healthy Maltese dogs

The most common cardiac measurements on thoracic radiography in veterinary medicine are vertebral heart size (VHS) and vertebral left atrial size (VLAS). Previously published studies have demonstrated evidence that reference ranges for these measures vary among different dog breeds, however reference ranges for Maltese breed dogs are currently lacking. We hypothesized that VHS and VLAS in healthy Maltese dogs would not be influenced by sex, age, or bodyweight. This retrospective, reference interval study aimed to describe reference intervals for VHS and VLAS in a sample of clinically healthy Maltese dogs and assess the intra- and interobserver variabilities for VLAS and VHS measurements. A total of 81 clinically healthy Maltese dogs were included, with healthy status being based on a complete cardiologic examination. Thoracic radiography in right lateral recumbency was performed for all dogs. The intra- and interobserver variability assessments of VHS and VLAS were based on measurements independently performed by three observers. The mean VHS was 9.53 ± 0.46 vertebrae (v). The median and interquartile range (IQR) for VLAS was 2 v (IQR, 1.8-2.1v). A statistically significant moderate positive correlation was observed between VHS and VLAS (P < .01, r = 0.416). Both VHS and VLAS showed an almost perfect intraobserver agreement. Interobserver agreement was almost perfect for VHS and substantial for VLAS. Findings supported previous studies recommending the use of breed-specific reference values for VHS and VLAS, and provided background data for future radiographic evaluations of Maltese dogs with clinical signs of cardiac disease.

The effects of activity, body weight, sex and age on echocardiographic values in English setter dogs

BACKGROUND

Breed-specific reference intervals improve echocardiographic interpretation and thereby reduce misdiagnoses, especially in athletic breeds.

OBJECTIVES

The objectives of the study were to examine transthoracic echocardiographic values in healthy adult English setter dogs and determine the effects of activity, body weight, sex and age on these values.

ANIMALS, MATERIALS AND METHODS

One hundred and one adult English setter dogs, recruited from local veterinary clinics and from the Norwegian English setter club, underwent routine transthoracic echocardiography. The population was stratified into two groups based on the reported level of activity. The effects of activity level, body weight, sex and age on echocardiographic variables were examined. Results were compared with published data from other breeds and from a pre-existing species-wide allometric model.

RESULTS

Of the 100 dogs between 19 months and 10 years of age included in the study, 72 were reported as very active and 28 as less active. Echocardiographic intervals were calculated for body size-independent echocardiographic variables. The upper limits of the intervals for left-atrial-to-aortic ratios and normalised left ventricular volumes exceeded those of various, previously published studies of other breeds. Normalised left ventricular dimensions exceeded published allometric 95^th percentile upper reference values in 13% of dogs in diastole and 32% of dogs in systole. More active dogs had larger cardiac dimensions than less active dogs; however, the activity level did not predict echocardiographic variables when included in a multiple regression model.

CONCLUSIONS

The study provides breed specific transthoracic echocardiographic values for English setter dogs, thereby contributing to improve diagnostic assessment of cardiac health in this breed.

Prediction of clinically important acquired cardiac disease without an echocardiogram in large breed dogs using a combination of clinical, radiographic and electrocardiographic variables

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 radiographs and echocardiographic images were measured to classify dogs as normal heart size (NHS), preclinical DCM, clinical DCM, preclinical MMVD (with cardiomegaly), clinical MMVD, or equivocal. Dogs with preclinical MMVD, without cardiomegaly, 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, respectively, while for VLAS, it was 0.891 and 0.722, respectively. Predictive models incorporating 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 examination abnormalities and arrhythmias were accounted for.

The vertebral heart scale on CT is correlated to radiographs in dogs

The vertebral heart scale (VHS) has long been used as an objective standard for evaluation of cardiac silhouette size on thoracic radiographs and plays a key role in the diagnosis as well as the assessment of the severity of canine heart disease. Based on our review of the literature, there has been no published study describing an objective method for measuring overall heart size using computed tomography (CT) in canine patients. The goals of this exploratory prospective method comparison study were to describe a method for objectively evaluating heart size on canine thoracic CT images, determine whether there was a correlation between the VHS when applied to a right lateral thoracic radiograph and a sagittal image of a thoracic CT scan, and determine the effect of cardiac phase on a VHS measured on CT. A method for measuring VHS on canine CT studies was defined. Data were collected on canine patients admitted to The Ohio State Veterinary Medical Center. Each patient received an ECG-gated thoracic CT immediately followed by a right lateral thoracic radiograph. The VHS was measured on non-gated, systolic, and diastolic sagittal CT reformatted images. Our results indicated that cardiac gating may not be necessary when assessing canine heart size on CT. When comparing the VHS on gated and non-gated CT to the VHS on radiographs, there was a moderate to high degree of correlation; however, there was a high degree of variability between CT and radiography.

Radiographic quantification of left atrial size in dogs with myxomatous mitral valve disease

Background

In the absence of echocardiography, identification of cardiomegaly via thoracic radiography is a necessary criterion for classification of disease severity in dogs with myxomatous mitral valve disease (MMVD).

Objective

Modified‐vertebral left atrial size (M‐VLAS) facilitates objective radiographic assessment of the left atrium (LA) in 2 dimensions and identifies LA enlargement more accurately than existing methods.

Animals

Sixty‐four dogs with various stages of MMVD and 6 control healthy dogs.

Methods

Retrospective case–control study. Medical records were searched for dogs with varying severity of MMVD. Modified‐vertebral left atrial size, vertebral left atrial size (VLAS), vertebral heart size (VHS), and radiographic left atrial dimension (RLAD) were measured from thoracic radiographs and compared with echocardiographically derived measurements.

Results

Positive correlation to LA/Ao was identified for M‐VLAS (r = 0.77, P < .001), VLAS (r = 0.76, P < .001), RLAD (r = 0.75, P < .001), and VHS (r = 0.67, P < .001). Receiver operating characteristic analyzes provided an area under the curve of 0.97 (95% CI, 0.94‐1.00) for M‐VLAS, which was superior to VHS (0.90, 95% CI, 0.94‐1.00, P = .03) in identifying dogs with LA/Ao ≥1.6. A cut‐off value of ≥3.4 vertebrae using M‐VLAS provided 92.7% sensitivity and 93.1% specificity in predicting LA enlargement.

Conclusions and clinical importance

M‐VLAS, which is superior to VHS, offers an accurate and repeatable way to radiographically identify LA enlargement in dogs with MMVD.

Evaluation of radiographic predictors of left heart enlargement in dogs with known or suspected cardiovascular disease

Radiographic assessment of heart size is important for clinical management of dogs with cardiovascular disease (CVDz). We sought to compare the ability of vertebral heart size (VHS), vertebral left atrial size (VLAS), and radiologists' assessment of left atrial size (RadLAE) to predict echocardiographic left atrial size (EchoLAE), an important marker of left heart disease severity. We also compared the ability of VHS and VLAS to predict echocardiographic criteria for ACVIM stage B2 (EchoB2) in dogs with myxomatous mitral valve disease (MMVD). This prospective observational study enrolled 183 dogs with known or suspected CVDz that had an echocardiographic examination and thoracic radiographs obtained within 24 h. Compared to increased VHS, VLAS >2.3 was a more accurate predictor of EchoLAE (P = .002). VLAS >2.3 and RadLAE (both P <.0001) were independently associated with EchoLAE but VHS was not (P = .45). Optimal cutoffs for VLAS and VHS to predict EchoLAE were >2.3 vertebrae (sensitivity [Sn] = 90.3%, specificity [Sp] = 73.6%) and >11.1 vertebrae (Sn = 75.8%, Sp = 76.0%), respectively. Diagnostic accuracy of VLAS (AUC 0.84, 95% CI 0.73-0.92) and VHS (AUC 0.78, 95% CI 0.66-0.88) to predict EchoB2 in dogs with subclinical MMVD (n = 64) were not significantly different (P = .17). Results demonstrate that VLAS and RadLAE were superior indicators of EchoLAE compared to VHS in dogs with known or suspected CVDz. Both VLAS and VHS are useful predictors of EchoB2 in dogs with subclinical MMVD. When echocardiography is unavailable, VLAS represents a useful radiographic measurement to aid clinical management of dogs with known or suspected CVDz.

A radiographic study of breed-specific vertebral heart score and vertebral left atrial size in Chihuahuas

Although echocardiography is the gold standard for the diagnosis of cardio-structural disease, thoracic radiography is a rapid, cost-effective, and widely accessible method for evaluating cardiac size in dogs. The vertebral heart score (VHS) and the vertebral left atrial size (VLAS) are established as objective measures of cardiomegaly on thoracic radiographs. However, several studies have shown significant variations in the VHS among different breeds. The Chihuahua is predisposed to both congenital and acquired cardiac diseases. The aim of this prospective, single-center, cross sectional study was thus to evaluate the VHS and the VLAS in healthy adult Chihuahua dogs. A total of 30 Chihuahuas were included. The VHS values in our sample population of Chihuahuas were 10.0 ± 0.6 (95% range, 8.9-11.0). This was significantly greater than the canine reference value of 9.7 ± 0.5 established by Buchanan and Bücheler (P = .002). The VLAS of Chihuahuas in our study was 1.8 ± 0.2 (95% range, 1.3-2.1). This was significantly lower than the values previously reported by Malcolm et al (2.07 ± 0.25; P = .0004). The VHS and the VLAS were not influenced by sex, body weight, short or long hair, and body condition score in normal Chihuahuas. Our results indicated that breed-specific reference values for radiographic VHS and VLAS are needed. In Chihuahuas, the values found in this study can be used as a normal reference in order to help avoid overinterpretation of cardiomegaly in these dogs.

Comparison of fluoroscopic cardiovascular measurements from healthy dogs obtained at end-diastole and end-systole

INTRODUCTION

Quantitative measurements are commonly implemented to objectively evaluate heart size in dogs. However, recent studies suggest that the phase of cardiac cycle can impact vertebral heart score, thereby potentially influencing clinical management. This study used fluoroscopy to assess the impact of the cardiac cycle on quantitative cardiovascular measurements in healthy dogs of various breeds.

ANIMALS, MATERIALS, AND METHODS

This was a prospective study. Multiple cardiac and respiratory cycles were recorded fluoroscopically. Peak inspiratory end-systole and end-diastole frames were captured from 49 dogs in right lateral recumbency. Vertebral heart score (VHS), cardiothoracic ratio (CTR), vertebral left atrial size (VLAS), and caudal vena cava diameter ratio (CVCDR) measurements were performed. Mean cardiac measurements were compared between cardiac cycle phases, and the impact of body condition score (BCS), weight, thoracic conformation, sex, and age was evaluated.

RESULTS

Cardiac cycle had a significant impact on VHS (mean difference: 0.36 ± 0.14 vertebral units between systole and diastole; p < 0.001) and CTR (mean difference: 2.2 ± 1.2% between systole and diastole; p < 0.001). Cardiac cycle had no significant impact on VLAS or CVCDR. Increasing BCS significantly increased variation between systole and diastole in CTR measurements (p = 0.024).

CONCLUSIONS

The cardiac cycle has a significant effect on VHS and CTR but does not impact VLAS or CVCDR. These findings should be taken into consideration during clinical use of these measurements, especially if a patient is being monitored for cardiac changes over time via serial radiographs.

Reprodutibilidade e repetibilidade de mensuração radiográfica da silhueta cardíaca em cães da raça poodle

Resumo Avaliou-se o potencial de reprodutibilidade e repetibilidade de um sistema semiautomático de mensuração radiográfica. Para isto foram mensurados, por intermédio de um software o vertebral heart score (VHS) e a área cardíaca normalizada (ACN) em imagens radiográficas de cães da raça poodle clinicamente normais e portadores de insuficiência valvar mitral. Dada a subjetividade da análise da silhueta cardíaca por diferentes observadores, acredita-se que mesmo com um sistema semiautomático essa avaliação poderia ser afetada pela experiência prévia do observador em radiodiagnóstico. Foram analisadas cinquenta e sete imagens radiográficas torácicas de cães atendidos em um hospital veterinário. As imagens foram analisadas por dois grupos de observadores com diferentes níveis de experiência em radiologia: (A) sem experiência (n = 2) e (B) com experiência (n = 2). Demonstrou-se boa repetibilidade e reprodutibilidade para o VHS independente da experiência em radiodiagnóstico, e para a ACN em observadores experientes e com familiaridade com o software.

Norwich terriers possess a greater vertebral heart scale than the canine reference value

Previous studies have demonstrated evidence that normal reference ranges for radiographic vertebral heart scale values can vary among dog breeds. The purpose of this retrospective, observational study was to determine whether the normal vertebral heart scale values published by Buchanan and Bücheler for lateral radiographs are applicable to the Norwich terrier. Secondary objectives were to determine if clinical signs of respiratory disease, age, sex, weight, body condition score, recumbency, or thoracic depth-to-width ratio had any influence on vertebral heart scale measurements in this breed. The electronic medical record systems of two universities were reviewed and Norwich terriers were included in the study if they had orthogonal thoracic radiographs performed and no historical or radiographic evidence of cardiopulmonary disease. A vertebral heart scale was calculated for each patient. Sixty-one client-owned, Norwich terrier dogs with no clinical signs of cardiovascular disease were evaluated. The vertebral heart scale for Norwich terriers without evidence of cardiac disease (10.6 ± 0.6) was found to be significantly greater than the canine reference value of 9.7 ± 0.5 initially established by Buchanan and Bücheler. No significant correlation was found between clinical signs of respiratory disease, sex, age, thoracic depth-to-width ratio or lateral recumbency, and vertebral heart scale. Norwich terriers with a body condition score ≥6 had a significantly higher vertebral heart scale than those with a body condition score ≤5. Breed-specific ranges and body condition scores need to be considered when interpreting vertebral heart scale values for Norwich terriers.

Greyhounds under general veterinary care in the UK during 2016: demography and common disorders

Background

The greyhound is a sighthound known for its speed and agility. Greyhounds were selectively bred as functional racing animals but increasingly are kept as pets in the UK, often after their racing careers are over. The VetCompass™ Programme collates de-identified clinical data from primary-care veterinary practices in the UK for epidemiological research. Using VetCompass™ clinical data, this study aimed to characterise the demography, mortality and common disorders of the general population of pet greyhounds under veterinary care in the UK.

Results

Greyhounds comprised 5419/ 905,544 (0.60%) dogs under veterinary care during 2016 from 626 clinics. Mean adult bodyweight was 29.7 kg (standard deviation [SD] 4.5 kg). Males (32.3 kg, SD 4.1 kg) were heavier than females (27.2 kg, SD 3.3 kg) (P < 0.001). Mean age was 7.6 years (SD 3.4). The most common colours were black (39.2%), black and white (20.8%), brindle (12.0%). Based on 474 deaths, median longevity was 11.4 years (range 0.2–16.5). Females (11.8 years) outlived males (11.2 years) (P = 0.002). The most common grouped causes of death were neoplasia (21.5%, 95% CI: 17.4–26.0), collapse (14.3%, 95% CI: 10.9–18.2) and musculoskeletal disorder (7.8%, 95% CI: 5.3–11.0). Based on a random subset of 2715/5419 (50.1%) greyhounds, 77.5% had > 1 disorder recorded during 2016. The most prevalent specific disorders were periodontal disease (39.0%, 95% CI: 37.2–40.9), overgrown nails (11.1%, 95% CI 10.0–12.4), wound (6.2%, 95% CI: 5.3–7.1), osteoarthritis (4.6%, 95% CI: 3.8–5.4) and claw injury (4.2%, 95% CI: 3.4–5.0).

Conclusions

These findings highlight the greyhound as a relatively common pet dog breed in the UK, accounting for 0.6% of dogs under primary veterinary care. Dental disease, trauma and osteoarthritis were identified as common health issues within the breed. Knowledge of common disorders can help greyhound breeders and regulators to prioritise breeding, rearing and racing management to mitigate some of the most prevalent issues. Greyhound rehoming organizations can also better inform adopters about prophylactic care.

ACVIM consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs

This report, issued by the ACVIM Specialty of Cardiology consensus panel, revises guidelines for the diagnosis and treatment of myxomatous mitral valve disease (MMVD, also known as endocardiosis and degenerative or chronic valvular heart disease) in dogs, originally published in 2009. Updates were made to diagnostic, as well as medical, surgical, and dietary treatment recommendations. The strength of these recommendations was based on both the quantity and quality of available evidence supporting diagnostic and therapeutic decisions. Management of MMVD before the onset of clinical signs of heart failure has changed substantially compared with the 2009 guidelines, and new strategies to diagnose and treat advanced heart failure and pulmonary hypertension are reviewed.

Breed-Specific Vertebral Heart Scale for the Dachshund

The objectives of this study were to determine a breed-specific vertebral heart scale (VHS) range for the dachshund and compare results to the established reference range of 9.7 ± 0.5, calculate inter-observer variability, and correlate VHS with echocardiography. Fifty-one normal dachshunds had radiographs and an echocardiogram performed. Five observers measured VHS to the nearest 0.25 vertebra. The data was analyzed using one-way analysis of variance, Wilcoxon Rank Sum test, Mann-Whitney rank sum test, calculation of reference and confidence intervals, Spearman rank-order correlations, and generation of intra-class correlations and confidence intervals. P &lt; .05 was considered significant. The median for right lateral VHS was significantly larger than left (10.3 [range 9.25–11.55] versus 10.1 [range, 8.7–11.31], p &lt; .0001). VHS for females was significantly larger than for males (left: 10.56 [9.2–11.31] versus 9.74 [8.7–10.88] and right: 10.8 [9.5–11.55] versus 9.99 [9.25–10.8], p = .0002). Observer consistency was high with an intra-class correlation coefficient of 0.95. No significant correlation was found between left atrial echocardiographic parameters and VHS. Results indicate normal dachshunds have a median VHS above the published generic canine reference range, and VHS can be reliably performed by observers with varying degrees of clinical experience.

Radiographic assessment of the cardiac silhouette in clinically normal large- and small-breed dogs

OBJECTIVE To determine manubrium heart scores (MHSs) from measurements of cardiac short-axis length (cSAL) and long-axis length (cLAL) relative to the corresponding manubrium length (ML) on thoracic radiographic views of dogs and assess correlation of MHSs with vertebral heart scores (VHSs). ANIMALS 120 clinically normal large-breed dogs (LBDs) and small-breed dogs (SBDs). PROCEDURES On right lateral views (RLVs) and ventrodorsal views (VDVs) for each dog, cSAL and cLAL were measured and expressed as a ratio; the cSAL:ML ratio (short-MHS), cLAL:ML ratio (long-MHS), and cSAL-and-cLAL:ML ratio (overall-MHS) were also calculated. The VHS was determined from the RLV. Correlation of VHS with MHS was assessed. RESULTS On RLVs and VDVs, mean cSAL:cLAL ratios were 0.77 (SD, 0.05) and 0.72 (SD, 0.05), respectively, in 60 LBDs and 0.81 (SD, 0.06) and 0.78 (SD, 0.06), respectively, in 60 SBDs. In LBDs, mean short-MHS, long-MHS, and overall-MHS were 2.1 (SD, 0.22), 2.7 (SD, 0.24), and 4.8 (SD, 0.5), respectively, on RLVs and 2.3 (SD, 0.26), 3.2 (SD, 0.34), and 5.4 (SD, 0.6), respectively, on VDVs. In SBDs, mean short-MHS, long-MHS, and overall-MHS were 2.4 (SD, 0.39), 2.9 (SD, 0.50), and 5.3 (SD, 0.83), respectively, on RLVs and 2.5 (SD, 0.44), 3.2 (SD, 0.51), and 5.8 (SD, 0.92), respectively, on VDVs. Mean VHSs were 10.73 (SD, 0.52) and 10.27 (SD, 0.81) in LBDs and SBDs, respectively. A significant correlation was identified between VHS and each MHS in LBDs. CONCLUSIONS AND CLINICAL RELEVANCE In the dogs evaluated, radiographic cardiac dimensions and MHSs were correlated. Validity of the MHS for cardiac dimension assessment in other healthy dogs and dogs with cardiac disease warrants investigation.

Vertebral scale system to measure heart size in thoracic radiographs of Indian Spitz, Labrador retriever and Mongrel dogs

AIM

To establish reference values of vertebral heart score (VHS) in Indian Spitz, Labrador retriever, and Mongrel dogs; to assess applicability of VHS in these three dog breeds; to determine if breed, recumbency side, gender, body weight, and thoracic depth (TD) to thoracic width (TW) ratio has an influence on the VHS measurement in these dog breeds.

MATERIALS AND METHODS

A total of 60, client owned, clinically healthy Indian Spitz (n=20, mean age = 4.25±2.15 years, body weight = 11.87±2.7 kg), Labrador retriever (n=20, mean age = 4.75±1.91 years, body weight = 27.31±5.43 kg), and Mongrel dogs (n=20, mean age = 4.25±1.52 years, body weight = 16.25±3.99 kg), having no radiological and clinical signs of cardiovascular or pulmonary disease were included in the study. All dogs were restrained manually and left lateral (LL) and right lateral (RL) radiographic views were obtained. The size of heart in lateral radiographs was calculated using VHS method. Besides, the TD, TW and TD: TW were calculated to determine the type of thoracic conformation in the dog breeds. In addition to this, the effect of breed, side of recumbency, gender, body weight, and TD to TW ratio on the calculation of VHS was determined.

RESULTS

VHS was calculated in all the animals of the breeds. VHS in Spitz and Labrador retriever was significantly (p<0.0001, p<0.0001, respectively) >9.7±0.5 v. RL and LL VHS in Mongrel dog was significantly (p<0.037) >9.7±0.5 v. Significant (p<0.05) differences in the VHS were observed among Spitz, Labrador retriever and Mongrel dogs, being higher for Labrador retriever followed by Spitz and Mongrel dogs. VHS in RL recumbency was significantly (p<0.001) greater than VHS in LL recumbency in all three breeds. LL and RL VHS correlated significantly with each other in Spitz (r=0.58; p=0.02), Labrador retriever (r=0.87; p<0.0001), and Mongrel dogs (r=0.93; p<0.0001). Significant (p<0.05) differences in the TD and TW were observed among Spitz, Labrador retriever, and Mongrel dogs. Non-significant effect of gender, body weight, and TD to TW ratio on the VHS measurement was observed in each dog breed.

CONCLUSION

Breed-specific VHS reference ranges should be used for the objective measurement of heart size in dogs. Furthermore, the radiographic view should also be taken into consideration to avoid any erroneous interpretation of cardiac enlargement in dogs.

Simpson's method of discs in Salukis and Whippets: Echocardiographic reference intervals for end-diastolic and end-systolic left ventricular volumes

BACKGROUND

Sighthound breeds are known to have different cardiac sizes and dimensions from other breeds; therefore, breed-specific references are required to avoid misinterpretation of echocardiographic findings. End-diastolic volume (EDV) and end-systolic volume (ESV) reference intervals derived from Simpson's method of discs (SMOD) do not exist for Salukis or Whippets.

OBJECTIVES

To establish EDV and ESV reference intervals for SMOD in Salukis and Whippets.

ANIMALS

110 Salukis and 119 Whippets.

METHODS

Reference intervals for SMOD with and without normalization to body surface area (BSA) were established using the right parasternal and left apical views in 93 healthy Salukis and 82 healthy Whippets. Volumes were compared between both echocardiographic views, genders, and racing and show pedigree dogs. The 90% reference intervals were calculated using the robust method.

RESULTS

Agreement between right-sided and left-sided echocardiographic views was good. Reference intervals indexed to body surface area (BSA) for Whippets were 59-109 mL/m² for end-diastolic volume index and 18-53 mL/m² for end-systolic volume index. Corresponding values for Salukis were 68-126 mL/m² for end-diastolic volume index and 27-64 mL/m² for end-systolic volume index. There were no indexed volume differences between male and female or racing and show pedigree dogs in both breeds. The non-normalized volumes significantly differed between genders.

CONCLUSIONS AND CLINICAL IMPORTANCE

Whippets and Salukis had larger systolic and diastolic left ventricular volumes compared with other breeds. This study provided echocardiographic reference intervals for SMOD-derived left ventricular volumes for these athletic breeds.

Plasma N-terminal pro-B-type natriuretic peptide concentration in healthy retired racing Greyhounds

BACKGROUND

N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a cardiac biomarker whose plasma concentration is high in some dogs with cardiopulmonary disease. NT-proBNP is a diagnostic tool that can be used to help determine if a patient has congestive heart failure. Greyhounds have functional heart murmurs, relative cardiomegaly, and high serum cTnI concentration.

OBJECTIVES

The purpose of the study was to evaluate the plasma concentration of NT-proBNP in healthy Greyhounds and compare it to non-Greyhound dogs.

METHODS

We prospectively evaluated healthy client-owned dogs including retired racing Greyhounds and non-Greyhounds. Plasma was obtained and transferred into tubes containing a protease inhibitor and submitted for a specific NT-proBNP ELISA assay.

RESULTS

The plasma NT-proBNP concentration in Greyhounds was significantly higher than in non-Greyhound control dogs (946 vs 632 pmol/L; P < .005); 46% of Greyhounds had NT-proBNP > 1000 pmol/L.

CONCLUSIONS

Plasma NT-proBNP concentration in Greyhounds is high and should be interpreted with caution.

Diagnostic accuracy of the vertebral heart score and other radiographic indices in the detection of cardiac enlargement in cats with different cardiac disorders

A retrospective search was conducted to evaluate the diagnostic accuracy of the vertebral heart score (VHS) and other related radiographic indices in the detection of cardiac enlargement associated with different cardiac disorders in the cat. One hundred and five cats with a complete echocardiographic examination and radiographic examination of the thorax with at least two orthogonal views were enrolled. Eighty-three cats had different cardiac disorders, 72 with left-sided cardiac disorders (LSCD) and 11 with right-sided cardiac disorders; 22 cats were free of cardiovascular abnormalities. Measurements of VHS and cardiac long and short axes on lateral (L) and dorsoventral or ventrodorsal radiographs were obtained. Receiver operating characteristic curves were calculated to evaluate the diagnostic accuracy of each radiographic index in differentiating between cats with cardiac disorders or cats with LSCD and cats without cardiac abnormalities and, among cats with LSCD, between those with no or mild left atrial enlargement (LAE) or those with moderate-to-severe LAE and healthy cats. The L-VHS at the cut-off of 7.9 had high diagnostic accuracy in distinguishing cats with LSCD and moderate-to-severe LAE from healthy cats, but all the other radiographic indices were moderately accurate in distinguishing between cats with overall cardiac disorders or LSCD, either with no or mild LAE and moderate-to-severe LAE, and healthy cats. The considered radiographic indices were also moderately accurate in predicting different degrees of LAE in cats with LSCD. Radiographic indices are reasonably specific, but less sensitive predictors of cardiac enlargement in cats with heart disorders.

Accuracy of radiographic vertebral heart score and sphericity index in the detection of pericardial effusion in dogs

OBJECTIVE

To evaluate the diagnostic accuracy of radiographically derived measurements of vertebral heart score (VHS) and sphericity index (SI) in the detection of pericardial effusion (PE) in dogs.

DESIGN

Retrospective case-control study. Animals-51 dogs with PE associated with various cardiac disorders, 50 dogs with left- or right-sided cardiac disorders without PE, 50 dogs with bilateral cardiac disorders without PE, and 50 healthy dogs.

PROCEDURES

Measurements of VHS on lateral (lateral VHS) and ventrodorsal (ventrodorsal VHS) radiographs, SI on lateral (lateral SI) and ventrodorsal (ventrodorsal SI) radiographs, and global SI (mean of lateral SI and ventrodorsal SI) were obtained. Receiver operating characteristic curves were calculated to evaluate the diagnostic accuracy of the radiographic indexes at differentiating dogs with PE from those with other cardiac disorders without PE.

RESULTS

Measurements of lateral and ventrodorsal VHS were significantly higher in dogs with PE, compared with values for all dogs without PE. Measurements of lateral, ventrodorsal, and global SI were significantly lower in dogs with PE, compared with values for all dogs without PE. Cutoff values of > 11.9, > 12.3, and ≤ 1.17 for lateral VHS, ventrodorsal VHS, and global SI, respectively, were the most accurate radiographic indexes for identifying dogs with PE.

CONCLUSIONS AND CLINICAL RELEVANCE

Cardiac silhouettes of dogs with PE were larger and more rounded, compared with those of dogs with other cardiac disorders without PE. Objective radiographic indexes of cardiac size and roundness were only moderately accurate at distinguishing dogs with PE from dogs with other cardiac disorders without PE.

A new method of computing the vertebral heart scale by means of direct standardisation

OBJECTIVES

The aim of this study was to describe and compare a simplified vertebral heart scale computation method (Objective VHS) with the original Buchanan method (Buchanan VHS).

METHODS

The Objective VHS was compared to the Buchanan VHS method in 42 dogs including 14 healthy dogs and 28 dogs with mitral insufficiency. For the Objective VHS, the sum of the length of the long and short axes of the cardiac silhouette obtained in centimetres using a metric ruler was subsequently converted into units of vertebral length by means of a direct standardization method. The Buchanan VHS was obtained as previously described.

RESULTS

No significant differences in vertebral heart scale values were found between the two methods in all dogs. There was a strong positive correlation (0·99) between Objective VHS and Buchanan VHS.

CLINICAL SIGNIFICANCE

The use of a direct standardization method based on a unit conversion allows -computation of vertebral heart scale values without transposing long and short axes to the cranial edge of T4.

Vertebral heart scores in eight dog breeds

The vertebral heart score (VHS) measurement is commonly used to provide a more objective measurement of cardiomegaly in canines. However, several studies have shown significant breed variations from the value previously established by Buchanan and Bücheler (9.7 ± 0.5). This study describes VHS measurements in Pug, Pomeranian, Yorkshire Terrier, Dachshund, Bulldog, Shih Tzu, Lhasa Apso, and Boston Terrier dog breeds. Dogs with two or three view thoracic radiographs, no subjective radiographic evidence of cardiomegaly, and no physical examination findings of heart murmurs or gallop rhythms were included in the study. The Pug, Pomeranian, Bulldog, and Boston Terrier groups were found to have a VHS significantly greater than 9.7 ± 0.5 (P < 0.00001, P = 0.0014, P < 0.0001, P < 0.00001, respectively). Body condition score (BCS) was found to have a significant effect on the VHS of Lhasa Apso group. Anomalous vertebrae in the thoracic column were associated with a significant increase in VHS of the Bulldog (P = 0.028) and Boston Terrier (P = 0.0004) groups. Thoracic depth to width ratio did not have a significant effect on VHS.

Radiographic appearance of the thorax of clinically normal alpaca crias

OBJECTIVE

To quantitatively and qualitatively assess the radiographic appearance of the thorax of clinically normal alpaca crias.

ANIMALS

21 clinically normal alpaca crias.

PROCEDURES

Left-right lateral (LR), right-left lateral (RL), dorsoventral (DV), and ventrodorsal (VD) projections of the thorax were acquired. To account for differences in cria size, measurements of thoracic structures were compared with other anatomic landmarks.

RESULTS

Mean ± SD vertebral heart scale was 9.36 ± 0.65 for LR projections, 9.36 ± 0.59 for RL projections, 8.21 ± 0.51 for DV projections, and 8.65 ± 0.57 for VD projections. Dimensions of the heart were compared with the length of the T3 through T5 vertebral bodies, third to fifth rib distance, and thoracic height and width, which provided additional methods of cardiac evaluation. For RL projections, mean ratio of the right cranial pulmonary artery diameter to the third rib width was 0.41 ± 0.10 and mean ratio of the right cranial pulmonary vein to the third rib width was 0.44 ± 0.10. Caudal lobar pulmonary vessels and the caudal vena cava were difficult to quantitatively assess on DV or VD projections. On lateral projections, the trachea was increased in diameter at the origin of the right cranial lobar bronchus. No qualitative differences were found between LR and RL radiographs. The lungs were generally better inflated on VD projections, with more separation of the heart and diaphragm.

CONCLUSIONS AND CLINICAL RELEVANCE

Establishment of radiographic values for alpaca crias should prove useful in assessment of thoracic disease in this species.

Clinical pathology of Greyhounds and other sighthounds

Owing to the development of Greyhounds as racing sighthounds, these dogs have acquired unique physiologic adaptations that distinguish them from other breeds. Reference intervals for many analytes in retired racing Greyhounds (RRGs) differ from those of other breeds; most of the hematologic differences have also been described in other sighthounds. In this review, we provide a survey of the literature on clinical pathology of Greyhounds and other sighthounds and results of laboratory testing, including analysis of CBCs, biochemical profiles, coagulation tests, and blood gases, in RRGs at The Ohio State University. Major clinicopathologic differences in this breed include higher RBC mass, creatinine concentration, glomerular filtration rate, activities of hepatic enzymes, and concentration of cardiac troponin, as well as lower WBC, neutrophil, and platelet counts, thromboelastographic values, and concentrations of serum haptoglobin, total globulins, and T4.

Avaliação radiográfica da silhueta cardíaca pelo método vertebral heart size em cães da raça Yorkshire Terrier clinicamente normais

Determinou-se valor médio do vertebral heart size (VHS) em cães da raça Yorkshire Terrier. Foram selecionados 30 cães clinicamente normais, com média de peso de 2,42±0,64kg e idades entre um e seis anos. Os animais foram submetidos ao exame radiográfico do tórax nas projeções lateral direita, ventrodorsal e dorsoventral. Foram feitas mensurações para avaliação cardíaca e da profundidade e largura torácicas. O valor médio de VHS foi de 9,9±0,6 vértebras na projeção lateral, 10,1±0,6 vértebras na projeção ventrodorsal e 10,0±0,6 vértebras na projeção dorsoventral. Não houve diferença entre esses valores. Cinco animais (16,7%) apresentaram VHS acima de 10,5 vértebras, valor sugerido como limite superior para a maioria das raças, em projeção lateral. Os valores de VHS correlacionaram-se com peso corporal nas projeções lateral e ventrodorsal. A razão profundidade:largura torácica apresentou valor médio de 0,75±0,06. Não foi observada correlação entre a qualidade do tórax e o VHS.

Serum cardiac troponin I concentration in retired racing greyhounds

BACKGROUND

Cardiac troponin I (cTnI) is a polypeptide found specifically in cardiac muscle tissue that has been used as a diagnostic and prognostic indicator of cardiomyopathy. Increases in cTnI are associated with myocardial pathologic processes. However, high serum cTnI concentrations have been observed in normal Greyhounds.

HYPOTHESIS

We hypothesized that Greyhounds have cTnI concentrations higher than non-Greyhound dogs, and that a separate reference range should be established for Greyhounds.

ANIMALS

Blood samples were collected from the jugular vein from a group of 20 healthy Greyhound blood donors.

METHODS

Analysis of serum cTnI was performed with an immunoassay system with a detection level of 0.01 ng/mL, as described previously. The Greyhound values were compared with 2 groups of Boxers with and without arrhythmogenic right ventricular cardiomyopathy (ARVC), and to a group of non-Boxer control dogs from a previous study.

RESULTS

The mean cTnI concentration in Greyhounds was significantly higher (P < .0001) than that in non-Greyhound control dogs, although not significantly different from normal Boxers (P= .50), or Boxers with ARVC (P= .58). Greyhound serum cTnI concentrations were in the range found in Boxers with ARVC. The proposed reference range for cTnI in Greyhounds is 0.05-0.16 ng/mL.

CONCLUSIONS AND CLINICAL IMPORTANCE

Greyhounds have a reference range for serum cTnI concentrations that differs from that of other previously published reference ranges for dogs of other breeds. Until a broader database and more precise reference range can be established, caution should be exercised in interpreting serum cTnI concentrations in Greyhounds with suspected cardiac disease.

Use of the vertebral heart score in coughing dogs with chronic degenerative mitral valve disease

The objective of the present study was to evaluate the usefulness of the vertebral heart score (VHS) in coughing dogs with chronic degenerative mitral valve disease (MVD). Survey thoracic radiographs of 90 dogs with a history of cough and clinical and echocardiographic evidence of MVD were evaluated by 2 independent observers. The observers were asked to first determine the origin of the cough as cardiac, non-cardiac or mixed and then to measure the VHS. Agreement regarding diagnosis of the origin of cough was obtained (kappa=0.64) in 69 dogs. Of these 69 dogs, 28 (41%), 32 (46%) and 9 (13%) had a cough of cardiac, non-cardiac and mixed origin, respectively. The dogs with a cough of non-cardiac origin had a significantly lower VHS (mean +/- SD, 11 +/- 0.9) compared with those of dogs with a cough of cardiac or mixed origin (12.8 +/- 1 and 12.9 +/- 0.9, respectively). Receiver operating characteristic curve analysis showed that a VHS < or = 11.4 is fairly accurate for exclusion of a cough of cardiac origin in dogs with MVD. The results indicate that the VHS may be an additional tool for differentiating the origin of cough in dogs with MVD.