Vertebral heart scores in eight dog breeds

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.

Radiographic Left Atrial Size Measurement of Dogs in Different Mitral Valve Disease Stages with Four Different Methods

The left atrial size increases (LAS) in patients with mitral valve disease (MVD) as the disease progresses. The vertebral left atrial size (VLAS), the modified-vertebral left atrial size (M-VLAS), and the radiographic left atrial dimension (RLAD) are methods reported to assess LAS on dogs' radiographs. All these methods transform the LAS into vertebral units. The thoracic inlet (TI) has been used as a reliable reference point to measure the cardiac silhouette of dogs with MVD in different stages. The objective of this study was to assess the clinical utility of measuring a dog LAS on right thoracic X-rays using the TI as a reference and determine whether it could differentiate dogs in different MVD stages. LAS was divided by the TI to obtain the thoracic inlet left atrial score (TILAS). This was a retrospective observational study including 135 apparently healthy dogs performed to assess their LAS with four different methods: VLAS, M-VLAS, RLAD, and TILAS. Thirty-six dogs from the general population were selected and compared to 100 dogs in different MVD stages. The TILAS was significantly different between the control dogs and MVD dogs, increasing with the disease stage: control dogs 0.51 ± 0.08, B1 0.57 ± 0.14, B2 0.75 ± 0.13, and C 0.84 ± 0.18. VLAS, M-VLAS, and RLAD also increased as the disease progressed, as shown in previous studies. The TILAS accuracy to distinguish MVD dogs with cardiac enlargement was comparable to VLAS, M-VLAS, and RLAD (AUC 0.91 vs. 0.93, 0.90, and 0.94 respectively). A TILAS > 0.8 can identify dogs with cardiac enlargement secondary to MVD.

Utility of vertebral left atrial size and vertebral heart size to aid detection of congestive heart failure in dogs with respiratory signs

BACKGROUND

Differentiating cardiogenic vs noncardiogenic causes of respiratory signs can be challenging when echocardiography is unavailable. Radiographic vertebral left atrial size (VLAS) and vertebral heart size (VHS) have been shown to predict echocardiographic left heart size, with VLAS specifically estimating left atrial size.

HYPOTHESIS/OBJECTIVES

Compare the diagnostic accuracy of VLAS and VHS to predict left-sided congestive heart failure (CHF) in dogs presenting with respiratory signs.

ANIMALS

One-hundred fourteen dogs with respiratory signs and radiographic pulmonary abnormalities.

METHODS

Retrospective cross-sectional study. Dogs had to have an echocardiogram and thoracic radiographs obtained within 24 hours. Diagnosis of CHF was confirmed based on the presence of respiratory signs, cardiac disease, LA enlargement, and cardiogenic pulmonary edema.

RESULTS

Fifty-seven dogs had CHF and 57 did not have CHF. Compared to VHS (area under the curve [AUC] 0.85; 95% confidence interval [CI], 0.77-0.91), VLAS was a significantly (P = .03) more accurate predictor of CHF (AUC, 0.92; 95% CI, 0.85-0.96). Optimal cutoff for VLAS was >2.3 vertebrae (sensitivity, 93.0%; specificity, 82.5%). Murmur grade (P = .02) and VLAS (P < .0001) were independently associated with CHF and VHS was not. Increased VHS (54%) was significantly (P = .01) more common than increased VLAS (24%) in dogs without CHF. Results were similar in a subsample of older and smaller dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

When echocardiography is unavailable, VLAS and murmur grade have clinically utility to aid in differentiating cardiogenic from noncardiogenic respiratory signs. These findings might be especially useful to help rule out CHF in dogs with increased VHS that present with respiratory signs.

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.

Cardiological Reference Intervals in Adult American Staffordshire Terrier Dogs

The aim of this study was to determine reference intervals (RI) for echocardiography, electrocardiography (ECG), vertebral heart score (VHS) measurement, and arterial systolic blood pressure (SBP) in American Staffordshire Terrier dogs. The study population included 29 clinically healthy AST dogs of different ages, genders, and body weights. SBP measurement, ECG, thoracic radiography, and echocardiography were performed on each dog. Compared to RIs available for the general population of dogs, the duration of the P wave and QRS complex was longer and VHS was higher. Moreover, the left ventricular dimension in diastole and systole, left atrial dimension, and end point to septal separation values were higher, while the interventricular septum in diastole and systole and aortic root diameter were lower compared to general similar average body weight. The AST breed has a different heart shape, which in this breed is more rounded compared to other dog breeds, especially the deep chest. The specific body structure and the shape of the heart had an impact on the results of the cardiological examination.

Holodiastolic Retrograde Flow in the Ascending Aorta in a Dog with Severe Aortic Regurgitation, Aortic Mineralization, and Systemic Hypertension

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Diastolic retrograde flow may be seen in the Ao in a dog with severe AR.

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Holodiastolic retrograde flow is described in people, typically in the descending Ao.

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Holodiastolic retrograde flow within the Ao has not been reported in dogs.

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Retrograde diastolic flow in the ascending Ao perfuses the CAs; undetectable on TTE.

Thoracic Vertebral Length-to-Height Ratio, a Promising Parameter to Predict the Vertebral Heart Score in Normal Welsh Corgi Pembroke Dogs

The vertebral heart score (VHS) is the sum of the ratio of the cardiac dimensions to the number of thoracic vertebrae, starting from the fourth thoracic vertebra (T4) to the intervertebral disk space (IVS). Breed-specific VHSs, in most cases, were different from the original reference value. Characteristics of the thoracic vertebrae and IVS may influence this variation. This study was conducted to investigate the characteristics of the T4 and IVS on the thoracic radiographs of Corgis in comparison with other small-to-medium breed dogs to evaluate the Corgi-specific VHSs in healthy dogs. The ratio of the T4's length/height (T4L/H) was significantly different among dog breeds but not the IVS between the T4 and T5. The T4L/H was highest in the Shih Tzu and lowest in Beagle dogs. The Corgi-specific VHS obtained from the ventrodorsal radiograph was significantly higher than that from the dorsoventral radiograph, but a significant difference was not observed between the right and left lateral radiographs. In contrast, the Corgi-specific VHS derived from the right lateral thoracic radiograph was significantly lower than the reference value. This may be correlated with the characteristics of the thoracic vertebrae of Corgis, which were slightly higher than those of the other breeds.

N-terminal pro-B-type natriuretic peptide levels in normotensive and hypertensive dogs with myxomatous mitral valve disease stage B

BACKGROUND

Systemic hypertension affects the heart, and to the best of our knowledge, no study has investigated the effects of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in dogs with myxomatous mitral valve disease (MMVD) stage B and systemic hypertension. This study aimed to investigate the blood level of NT-proBNP and assess the selected echocardiographic variables in dogs with MMVD stage B according to the presence of systemic hypertension or normal blood pressure and in dogs without MMVD.

RESULTS

The study group comprised 37 dogs with stage B MMVD (normotensive group, n = 30; systemic hypertension group, n = 7) and 13 dogs without MMVD. We evaluated NT-proBNP, blood pressure, complete blood count (CBC), and serum chemistry in all 50 dogs. We performed electrocardiography, radiography, and echocardiography on 44 dogs (37 dogs with MMVD and 7 dogs without MMVD). The NT-proBNP concentrations showed significant intergroup differences (p < 0.001). Normotensive dogs with MMVD stage B (median [interquartile range]: 1083.5 [574.8-1912.8] pmol/L) and hypertensive dogs with MMVD stage B (2345.0 [1812.5-2533.0] pmol/L) showed significantly higher NT-proBNP concentrations than dogs without MMVD (504 [430-774] pmol/L, p = 0.009 and p < 0.001, respectively), and dogs in the systemic hypertension group showed significantly higher NT-proBNP concentrations than those in the normotensive group (p = 0.046). Mitral valve regurgitation velocity was significantly higher in dogs in the systemic hypertension group (6.11 [6.07-6.24] m/s) than in those in the normotensive group (5.53 [5.17-5.95] m/s, p = 0.006). The left atrial to aortic root ratio (LA/Ao), E-peak velocity, and left ventricular end-diastolic internal diameter corrected for body weight (LVIDDN) were significantly lower in dogs without MMVD than in dogs with MMVD stage B.

CONCLUSIONS

These findings suggest that NT-proBNP concentrations are higher in dogs with MMVD stage B with systemic hypertension than in normotensive dogs with MMVD stage B. Therefore, clinicians should be aware that NT-proBNP could be elevated in the presence of systemic hypertension.

Interactions between Humans and Dogs during the COVID-19 Pandemic: Recent Updates and Future Perspectives

COVID-19 is one of the deadliest epidemics. This pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but the role of dogs in spreading the disease in human society is poorly understood. This review sheds light on the limited susceptibility of dogs to COVID-19 infections which is likely attributed to the relatively low levels of angiotensin-converting enzyme 2 (ACE2) in the respiratory tract and the phylogenetic distance of ACE2 in dogs from the human ACE2 receptor. The low levels of ACE2 affect the binding affinity between spike and ACE2 proteins resulting in it being uncommon for dogs to spread the disease. To demonstrate the role of dogs in spreading COVID-19, we reviewed the epidemiological studies and prevalence of SARS-CoV-2 in dogs. Additionally, we discussed the use of detection dogs as a rapid and reliable method for effectively discriminating between SARS-CoV-2 infected and non-infected individuals using different types of samples (secretions, saliva, and sweat). We considered the available information on COVID-19 in the human-dog interfaces involving the possibility of transmission of COVID-19 to dogs by infected individuals and vice versa, the human-dog behavior changes, and the importance of preventive measures because the risk of transmission by domestic dogs remains a concern.

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.

RADIOGRAPHIC MEASUREMENT OF VERTEBRAL HEART SCALE IN KOREAN WILD RACCOON DOGS (NYCTEREUTES PROCYONOIDES KOREENSIS)

Raccoon dogs (Nyctereutes procyonoides koreensis), which belong to the Canidae family, are the second most injured wildlife animals rescued by the Gangwon Wildlife Medical Rescue Center. Various imaging evaluation methods including echocardiography have been developed, but thoracic radiography remains essential for the diagnosis and management of heart disease in dogs. In particular, vertebral heart scale (VHS) measurement is usually used to evaluate the dimensions of the heart silhouette on thoracic radiographs and can measure cardiomegaly more objectively. The VHS of 50 raccoon dogs without cardiac diseases were measured using thoracic radiography in right lateral (RL) and ventrodorsal (VD) recumbent positions. The VHS in the RL view of 50 raccoon dogs was 9.03 ± 0.52 vertebrae (v), which was slightly smaller than the VHS measured in the VD view of 46 raccoon dogs (9.79 ± 0.84 v). In addition, the thoracic morphology of raccoon dogs was determined to be intermediate (thoracic depth-to-width ratio, 0.75-1.25), and thoracic morphology, gender, and weight were not significantly correlated with VHS. The VHS of raccoon dogs in this study will help veterinarians diagnose potential cardiac diseases in raccoon dogs.

Methods of Radiographic Measurements of Heart and Left Atrial Size in Dogs with and without Myxomatous Mitral Valve Disease: Intra- and Interobserver Agreement and Practicability of Different Methods

Dogs suffering from Myxomatous Mitral Valve Disease (MMVD) show a potential heart enlargement, especially in the left atrium, detectable by radiography. Due to digital radiography, different radiographic measurements estimate cardiac size quite uncomplicatedly. The Vertebral Heart Size (VHS), Radiographic Left Atrial Dimension (RLAD), Left Atrial Width (LAWidth), and the Vertebral Left Atrial Size (VLAS) used anatomical landmarks for measuring cardiac size in relation to the vertebral column. This study aimed to compare VHS, RLAD, LAWidth, and VLAS measured in conventional and inverted radiographs by veterinarians with different levels of experience in healthy dogs and dogs with MMVD. The reliability and user-friendliness of these measurements were evaluated, and the staging was compared to the echocardiography staging. A total of 50 unaffected dogs and 150 dogs with MMVD in stages B1, B2, and C were assessed. Three veterinarians with different levels of experience examined 200 conventional radiographs and their corresponding inverted radiographs blinded to the echocardiographic and clinical examination results. Analyses were performed to compare the measurements’ grading and determine anatomical landmarks with measurement difficulties. Additionally, inter- and intraobserver agreement was assessed using intraclass correlation coefficient, and the agreement between radiographic and echocardiographic staging was compared using the kappa coefficient. The VHS, LAWidth, and VLAS were easier to define than the RLAD. The interobserver agreement was almost perfect for VHS (0.962) and good for the other radiographic measurements (RLAD: 0.778, LAWidth: 0.772, VLAS: 0.858). The VHS assigned the most dogs to the correct stage. However, VHS, RLAD, LAWidth, and VLAS presented an almost perfect intraobserver agreement. The dorsal left atrial margin of the RLAD was the most difficult measurement point to identify. The VHS is the most reproducible radiographic method for measuring the canine heart size and shows the highest agreement with echocardiography. An observer-related influence could be detected for RLAD, LAWidth, and VLAS.

Comparison of different radiographic scores with associated echocardiographic measurements and prediction of heart enlargement in dogs with and without myxomatous mitral valve disease

INTRODUCTION

Staging of myxomatous mitral valve disease (MMVD) requires an echocardiographic examination along with thoracic radiographs. The aims of this study were to calculate mean values for radiographic scores vertebral heart size (VHS), left atrial width (LA_Width), radiographic left atrial dimension (RLAD), and vertebral left atrial size (VLAS) in conventional and grayscale inverted images in healthy dogs and dogs with different stages of MMVD, and to find cutoff values for a stage assignment.

ANIMALS

One hundred fifty dogs in different stages of MMVD and 50 unaffected dogs were evaluated.

METHODS

Radiographic scores, echocardiographic left atrium-to-aorta ratio and normalized left ventricular internal dimension at end-diastole, and results of a clinical examination were obtained. Analyses were performed to evaluate the correlation between radiographic scores and echocardiographic values, to determine cutoff values for a radiographic stage assignment, and to compare measurements in conventional and inverted radiographs.

RESULTS

After excluding breed-specific higher VHS, the means of VHS, LA_Width, RLAD, and VLAS were similar in the control group and stage B1. All radiographic scores increased in stages B2 and C. The cutoff values identifying heart enlargement, and therefore differentiating stages B1 and B2, were 11.0 for VHS, 1.8 for LA_Width, 2.0 for RLAD, and 2.3 for VLAS. Besides RLAD, scores were similar in conventional and inverted radiographs.

CONCLUSION

Cutoff values for the different radiographic scores for stage assignment were calculated. Radiographic cardiac scores using either conventional or inverted grayscale could be a tool to differentiate between different stages of MMVD when echocardiography is unavailable.

Breed-specific values for vertebral heart score (VHS), vertebral left atrial size (VLAS), and radiographic left atrial dimension (RLAD) in pugs without cardiac disease, and their relationship to Brachycephalic Obstructive Airway Syndrome (BOAS)

This prospective study aims to establish reference ranges for vertebral heart score (VHS), vertebral left atrial size (VLAS), and radiographic left atrial dimension (RLAD) in pugs. The impact of clinical severity of Brachycephalic Obstructive Airway Syndrome (BOAS), gender, body condition score, and body weight on VHS, VLAS, and RLAD were investigated. Intra- and interobserver correlation was determined. Correlation of radiographic scores to echocardiographic left atrial dimension was inspected. Additionally, for VLAS and RLAD, correlation to VHS was examined. Additionally, an assessment of thoracic and vertebral malformations was performed. Forty-seven privately owned pugs underwent physical examination, echocardiography, and thoracic radiography to determine cardiac health. Thirty-two pugs were eligible for establishing reference ranges for VHS in right lateral radiographs, which was 11.25 ± 0.62 (95% range, 10.1–12.8). Reference ranges for VHS in left lateral, and for VLAS and RLAD in right lateral radiograph were determined in 30 pugs. The VHS in left lateral radiograph was 11.01 ± 0.70 (95% range, 9.4–12.6), VLAS was 1.96 ± 0.38 (95% range, 1.1–2.8), and RLAD was 1.59 ± 0.34 (95% range, 0.7–2.4). Clinical severity of BOAS did not show any impact on radiographic measurements. For VLAS, a significant correlation to VHS was detected by all observers. No other variables had a consistent influence on the radiographic scores given by all observers. Interobserver agreement was almost perfect for VHS (0.89 on right lateral and 0.91 on left lateral image), moderate for VLAS (0.49), and fair for RLAD (0.22). More than one third of the entire study population (18 of 47 pugs) showed at least one thoracic cavity or spine abnormality, often leading to considerable changes in vertebral body shape and size.

An automated deep learning method and novel cardiac index to detect canine cardiomegaly from simple radiography

Since most of degenerative canine heart diseases accompany cardiomegaly, early detection of cardiac enlargement is main priority healthcare issue for dogs. In this study, we developed a new deep learning-based radiographic index quantifying canine heart size using retrospective data. The proposed "adjusted heart volume index" (aHVI) was calculated as the total area of the heart multiplied by the heart's height and divided by the fourth thoracic vertebral body (T4) length from simple lateral X-rays. The algorithms consist of segmentation and measurements. For semantic segmentation, we used 1000 dogs' radiographic images taken between Jan 2018 and Aug 2020 at Seoul National University Veterinary Medicine Teaching Hospital. The tversky loss functions with multiple hyperparameters were used to capture the size-unbalanced regions of heart and T4. The aHVI outperformed the current clinical standard in predicting cardiac enlargement, a common but often fatal health condition for small old dogs.

Reference ranges for standard-echocardiography in pugs and impact of clinical severity of Brachycephalic Obstructive Airway Syndrome (BOAS) on echocardiographic parameters

BACKGROUND

Echocardiographic measurements may be influenced by breed-specific characteristics. Therefore, this study aims to establish reference values for standard echocardiographic measurements in pugs by investigating the influence of age, sex, heart rate, body weight and Brachycephalic Obstructive Airway Syndrome (BOAS). Sixty-two privately owned pugs underwent physical examination, blood sample collection, non-invasive blood pressure measurements and echocardiography. Influences of independent variables on echocardiographic measurements were examined using a multiple linear regression analysis model. For the entire study population, 95% prediction intervals were generated. Further, reference ranges for subcategories of clinical severities of BOAS were provided. Selected echocardiographic measurements of pugs were compared to reference values of previous studies generated from various breeds.

RESULTS

In the study, a total of fifty-one privately owned pugs aged between two and 10 years were included for establishing reference ranges. Mainly body weight, but also age, sex and heart rate had influence on several echocardiographic parameters. The clinical grading of BOAS was conducted in 42 pugs. Except for pulmonic peak velocity (Pvel), which declined with increasing severity of BOAS, clinical symptoms of upper airway disease did not have significant impact on echocardiographic measurement results. Significant deviations, however, of left ventricular (LV) internal dimension (LVID), interventricular septum (IVS), LV posterior wall (LVPW), and tricuspid annular plane systolic motion excursion (TAPSE) compared to interbreed reference values were observed.

CONCLUSIONS

Breed-specific reference ranges for echocardiographic values with special regard to BOAS are provided to enable a more accurate assessment of cardiac health in pugs.

Polyunsaturated Fatty Acid EAB-277® Supplementation Improved Heart Rate Variability and Clinical Signs in Tracheal Collapse Dogs

Canine tracheal collapse is a progressive disease in small breed dogs resulting from chronic inflammation of the tracheal mucosal lining. Polyunsaturated fatty acid EAB-277® is one of the nutraceuticals that can alleviate inflammation and oxidative stress. Heart rate variability (HRV) is a prognostic tool related to sympathovagal balance and oxidative stress level, which is widely used with cardiorespiratory diseases. However, the effect of EAB-277® on HRV in tracheal collapse dogs has rarely been investigated. In this study, 26 tracheal collapse dogs were divided into two groups. In the control group, the dogs received the standard treatment, whereas the dogs in the EAB-277® group received standard treatment combined with EAB-277®. After being treated for 5 weeks, changes in radiographic findings, blood profiles, serum malondialdehyde, inflammatory markers, and HRV were evaluated. This study found that clinical signs were improved in both groups (p < 0.05). However, serum malondialdehyde (MDA), Interleukin-6 (IL-6), and Tumor necrosis factor-alpha (TNF-α) were decreased only in the EAB-277® group after treatment for five weeks (p < 0.05) and the mean percent change of MDA, IL-6, and TNF-α at week five compared to baseline in the EAB-277® group was greater than in the control group (p < 0.05). Additionally, greater sympathovagal imbalance indicated by decreased standard deviation of all normal R-R intervals (SDNN) and standard deviation of the averaged R-R intervals for all 5-minutes segments (SDANN) was found in the control group at week five compared to baseline (P < 0.05), whereas EAB-277® improved SDNN and SDANN and decreased low frequency/high-frequency component (LF/HF ratio) after being treated for five weeks (P < 0.05). This study demonstrates that EAB-277® improves clinical signs and attenuates HRV impairment by reducing oxidative stress and inflammation in tracheal collapse dogs.

Myxomatous mitral valve disease in Miniature Schnauzers and Yorkshire Terriers: 134 cases (2007-2016)

OBJECTIVE

To characterize features of myxomatous mitral valve disease (MMVD) in Miniature Schnauzers and Yorkshire Terriers.

ANIMALS

69 Miniature Schnauzers and 65 Yorkshire Terriers, each with MMVD.

PROCEDURES

Medical record data for each dog were collected; the study period was January 2007 through December 2016. If available, radiographic data were evaluated, and a vertebral heart scale score was assigned for each dog. Statistical analysis was performed with Student t and Fisher exact tests.

RESULTS

Compared with Yorkshire Terriers, the prevalence of MMVD was significantly higher in Miniature Schnauzers and affected dogs were significantly younger at the time of diagnosis. Miniature Schnauzers were significantly more likely to have mitral valve prolapse and syncope, compared with Yorkshire Terriers. Yorkshire Terriers were significantly more likely to have coughing and have had previous or current treatment with cardiac medications, compared with Miniature Schnauzers. There was no statistical difference between breeds with regard to abnormally high vertebral heart scale scores or radiographic evidence of congestive heart failure.

CONCLUSIONS AND CLINICAL RELEVANCE

With regard to MMVD, features of the disease among Miniature Schnauzers and Yorkshire Terriers were similar, but there were also a few discernable differences between these 2 breeds and from historical findings for dogs with MMVD of other breeds. Clinical signs at the time of diagnosis differed between the 2 breeds, which may have reflected concurrent breed-specific conditions (sick sinus syndrome or airway disease [eg, tracheal collapse]). Future work should include prospective studies to provide additional information regarding the natural progression of MMVD in these dog breeds.

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.

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.

DETERMINATION OF VERTEBRAL HEART SCALE AND ECHOCARDIOGRAPHIC MEASUREMENTS IN HEALTHY ANESTHETIZED AFRICAN WILD DOGS (LYCAON PICTUS) IN HUMAN CARE

Cardiac disease is an important cause of mortality in African wild dogs in human care. Vertebral heart scale (VHS) is a well-documented objective measure of cardiac size and is commonly used in domestic dogs. The VHS of 63 clinically healthy African wild dogs housed in zoological institutions was retrospectively calculated. Using the robust method of reference interval (RI) calculation, the RI for VHS in captive African wild dogs was 9.3-10.8. Echocardiographic measurements from 16 clinically healthy and 2 African wild dogs with preclinical dilated cardiomyopathy are reported. The cardiac biomarkers N-terminal pro-B-type natriuretic peptide (NT-proBNP) and cardiac troponin I (cTnI) were measured in a subset of African wild dogs. The median plasma NT-proBNP measurement was 845 pM/L (range 366-1,388) and the median serum cTnI measurement was 0.02 ng/ml (0.01-0.04). These data can be used for the assessment and identification of cardiac disease in this endangered species.

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.

The Longitudinal Outcome Of Canine (K9) myxomatous mitral valve disease (LOOK-Mitral registry): Baseline characteristics

INTRODUCTION

The Longitudinal Outcome Of Canine (K9) myxomatous mitral valve disease (MMVD) registry (LOOK-Mitral registry) was established to describe the natural history and predictors of outcome in dogs affected by MMVD. This study was intended to describe the baseline characteristics of dogs in the LOOK-mitral registry.

ANIMALS

Dogs with echocardiographic evidence of MMVD were prospectively enrolled by thirteen referral centers.

RESULTS

A total of 6102 dogs with MMVD were included. The median age was 10 years (1-19 years), and mixed breed was the most common breed (n = 1,360, 22%). Concomitant diseases were reported in 2459 dogs with chronic respiratory diseases occurring most frequently (14%), followed by the presence of azotemia (6%) and orthopedic diseases (5%). Regarding disease severity, 65% of dogs were in ACVIM Stage-B1, 15% in Stage-B2, and 20% in Stage-C. Dogs in Stage-B1 were younger (p<0.001) than dogs in other stages. Murmur intensity, heart rate during physical examination, and radiographic vertebral heart score were positively associated with the stage. Dogs in Stage-C were more likely to have tachypnea (p<0.001), dyspnea (p<0.001), cough (p<0.001), syncopal episodes (p<0.001), and tachyarrhythmias (p<0.001) compared to dogs in Stage-B1 and B2. Echocardiographic indices of left atrial and ventricular size were positively correlated with the ACVIM stage. Interestingly, 4% of dogs that weighed <20 kg had an increased normalized end-systolic left ventricle internal diameter (>1.26).

CONCLUSIONS

This study contributes to a better understanding of the clinical characteristics of dogs affected by MMVD and provides new findings that may be of clinical relevance.

Vertebral heart score to evaluate cardiac size in thoracic radiographs of 124 healthy rats (Rattus norvegicus)

Dilated cardiomyopathy is a relatively common disease in pet rats (Rattus norvegicus); however, there is a lack of radiographic references for the normal cardiac size in this species. The aim of this prospective, anatomical and reference interval study was to establish quantitative radiographic reference range measurements for the vertebral heart score (VHS) in rats. Right lateral (RL), ventrodorsal (VD), and dorsoventral (DV) radiographs of clinically healthy rats (n = 124) were evaluated. Measurements were performed by 2 expert readers who were unaware of signalment data. The mean values and references intervals of VHS were 7.7 and 7.0-8.5 for the RL, 7.5 and 6.6-8.6 for the VD, and 7.9 and 6.9-9.0 for the DV, with VHS values greater in males than in females. The measurements reported in this study can be used by the clinician as an objective tool to evaluate cardiac size in rats, in order to improve the diagnosis and treatment of cardiac diseases.

Evaluation of bronchial narrowing in coughing dogs with heart murmurs using computed tomography

Background

The origin of cough in dogs with heart murmurs is controversial, because the cough could be primary cardiac (eg, pulmonary edema, bronchi compression by left‐sided cardiomegaly) or respiratory (eg, bronchomalacia, other bronchial or bronchiolar disease, interstitial lung disease) in origin.

Hypothesis/Objectives

To study the association between left atrium (LA) dilatation and cardiomegaly and bronchial narrowing in coughing dogs with heart murmurs using computed tomography (CT).

Animals

Twenty‐one client‐owned coughing dogs with heart murmurs and 14 historical control dogs.

Methods

Dogs with cough and murmur were prospectively recruited over 4 months. Cervical and thoracic radiography, echocardiography, and thoracic CT were performed in enrolled dogs. Control dogs, with no disease on thoracic CT and no records of heart murmur and coughing, were gathered from the institution's computerized database. Degree of bronchial narrowing was assessed using the bronchial‐to‐aorta (Ao) ratio, measured by 3 radiologists blinded to the clinical findings. After identifying bronchi that were significantly narrowed in dogs with murmur compared to controls, the relationship between degree of narrowing and LA/Ao ratio (measured echocardiographically) and vertebral heart scale (VHS) measured radiographically was studied in dogs with murmur using mixed‐effects regression.

Result

Significant narrowing was identified for all left‐sided bronchi and the right principal, middle, and caudal bronchi in the coughing dogs, compared with controls. Increasing LA size and VHS were significantly inversely associated with diameter for all left‐sided and right‐sided bronchi indicated above.

Conclusion and Clinical Importance

Results indicate an association between LA enlargement and cardiomegaly and bronchial narrowing and support heart size‐associated exacerbation of cough in dogs with murmurs.

Radiographic anatomy of the heart of fruit bats

As the only mammal that can fly, bats have organ systems with a unique morphophysiology. One of the highlights is the heart and blood circulation system, which must be able to meet the needs of blood and oxygen supply when flying. This study examined the radiography of the normal condition of the heart organ in 3 species of fruit bats, namely Cynopterus titthaecheilus, Cynopterus brachyotis and Rousettus leschenaultii using radiological silhouette analysis and clock analogy. The results showed that the heart positions of the three bat species tend to be tilted to the left with the apex moving away from the midsagittal plane. Analysis of intercostal space (ICS) value and vertebral heart score (VHS), and evaluation of radiographic features showed R. leschenaultii has a relatively larger heart size than the other two species. All three bat species have a higher VHS than mammals in general. Radiographic images obtained, and interpretation results show the position, size and normal heart parts of the three bat species. They will be useful in diagnostic efforts related to heart problems in these three species.

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.

Estimation of vertebral heart size and cardiothoracic ratio in Persian cats

The study aimed to determine the reference values related to vertebral heart size (VHS) and cardiothoracic ratio (CTR), which are effective in the evaluation of the thorax diseases and especially cardiomegaly of the brachycephalic cats using the morphometric data of thorax and heart obtained from the radiographic images of the thoracic region of the Persian cats. It was determined that lying position during radiography did not affect VHS and CTR values. Also, the sex factor did not have a significance on these values. The fact that the VHS value of 8.16 thoracic vertebrae averagely found in the Persian cats is higher than 7.5 thoracic vertebrae value averagely stated in the studies conducted with the cats of different breeds is considered since the breed is brachycephalic.

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.

Interobserver variability of radiographic methods for the evaluation of left atrial size in dogs

The objectives of this retrospective, observer agreement study were to (a) test variability of radiographic left atrial dimension (RLAD) and vertebral left atrial size (VLAS) measurements among observers with different levels of expertise in thoracic radiology and cardiology, (b) assess whether one method is better than the other in detecting left atrial enlargement (LAE), and (c) assess the agreement among RLAD, VLAS, and American College of Veterinary Internal Medicine (ACVIM) classes. Seventy-four dogs (eight healthy and 66 with mitral valve disease) with thoracic radiographs and echocardiography performed on the same day were reviewed. Thirty showed echocardiographic LAE. Left atrial dimension was quantified using RLAD and VLAS by six different operators with three levels of clinical experience in veterinary cardiology/radiology. Vertebral heart score and fourth thoracic vertebra (T4) were also measured. Differences in T4, vertebral heart score (VHS), RLAD, and VLAS measurements were found among six operators and among the three levels of clinical expertise as well as between veterinary cardiology readers and veterinary radiology readers (P < .05). The area under the receiver operating characteristic (AUC) curve for VHS showed good performances for all observers and level and type of expertise; the AUC for RLAD and VLAS was suboptimal only for the radiology student. Our RLAD and VLAS cutoffs (1.9 and 2.43 v, respectively) were better related to qualitative radiographic than quantitative echocardiographic LAE evaluation. Radiographic LA dimension and VLAS showed an increase proportional to the worsening of the ACVIM class. In conclusion, these results allow us to affirm that RLAD and VLAS are reproducible measurements for detecting LAE. Better performances are associated with clinical expertise and background.

Use of radiographic measurements to diagnose stage B2 preclinical myxomatous mitral valve disease in dogs

OBJECTIVE

To investigate the usefulness of radiographic measures of the left atrium and ventricle as surrogates for echocardiographic criteria in identifying dogs with stage B2 preclinical myxomatous mitral valve disease (MMVD).

ANIMALS

56 client-owned dogs with preclinical mitral regurgitation attributed to MMVD examined between April 19, 2016, and November 22, 2017.

PROCEDURES

Medical records were retrospectively searched, and data collected included age, body weight, heart murmur grade, and echocardiographic and radiographic measurements. Dogs were grouped according to whether they did (case dogs) or did not (control dogs) meet echocardiographic criteria used to identify dogs with stage B2 MMVD. Measurements for lateral thoracic radiographic variables normalized to vertebral body units (VBUs) were obtained, and results were analyzed to identify variables that could best discriminate between case and control dogs.

RESULTS

Three radiographic variables of left atrial size (vertebral left atrial size [VLAS], left atrial width, and the combined variable of VLAS + left atrial width) most accurately distinguished control dogs from case dogs, and the VLAS was the simplest and fastest to perform in a clinical setting. The optimal cutoff for VLAS was 2.5 VBUs (sensitivity, 70%; specificity, 84%; and likelihood ratio, 4.38), with VLAS ≥ 2.5 VBUs for case dogs. The maximum specificity cutoff for VLAS was 3.0 VBUs (sensitivity, 40%; specificity, 96%; and likelihood ratio, 10.0), with VLAS ≥ 3.0 VBUs for case dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that when echocardiography is unavailable, radiographic VLAS ≥ 3 VBUs could be used with minimal risk of false-positive diagnosis of stage B2 MMVD in dogs.

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.

Utility of radiographic measurements to predict echocardiographic left heart enlargement in dogs with preclinical myxomatous mitral valve disease

BACKGROUND

Evaluation of left heart size helps determine disease severity in dogs with myxomatous mitral valve disease (MMVD).

HYPOTHESIS/OBJECTIVES

Determine the ability of radiographic vertebral heart size (VHS) and vertebral left atrial size (VLAS) to predict LHEECHO in dogs with preclinical MMVD.

ANIMALS

Seventy client-owned dogs with MMVD and no historical or present clinical or radiographic evidence of congestive heart failure (CHF).

METHODS

Retrospective cross-sectional study of dogs with same-day echocardiography and thoracic radiography. Receiver-operating characteristic (ROC) curves were used to assess the ability of VHS, VLAS, and VHS + VLAS to discern dogs with and without LHEECHO , and clinically relevant cutpoints for these radiographic measurements were selected.

RESULTS

The ability of VHS and VHS + VLAS to predict LHEECHO was moderate (area under the curve [AUC]VHS = 0.851; 95% CI, 0.762-0.941; AUCVHS + VLAS = 0.865; 0.783-0.947), and performance of VLAS and VHS + VLAS was not different from that of VHS alone. A VHS cutpoint of >10.8 had sensitivity = 91.1% (76.3%-98.1%) and specificity = 69.4% (51.9%-83.7%) for predicting LHEECHO . A cutpoint of >11.7 had sensitivity = 32.4% (17.4%-50.5%) and specificity = 97.2% (85.5%-99.9%) for predicting LHEECHO . Thirty (43%) of the 70 dogs had a VHS value of 10.9 to 11.7.

CONCLUSIONS AND CLINICAL IMPORTANCE

Vertebral heart size >11.7 identified dogs with LHEECHO and VHS ≤ 10.8 excluded dogs with LHEECHO . A large percentage of dogs had VHS values intermediate to these cutpoints.

Use of cardiac sphericity index and manubrium heart scores to assess radiographic cardiac silhouettes in large-and small-breed dogs with and without cardiac disease

OBJECTIVE

To evaluate the usefulness of manubrium heart scores (MHSs) in distinguishing between dogs with and without cardiac disease.

ANIMALS

184 client-owned dogs with (n = 64) and without (120) cardiac disease.

PROCEDURES

Medical records, including thoracic radiographic images, of dogs that either had echocardiographically confirmed moderate to severe cardiac disease with cardiomegaly (case dogs) or were healthy and without evidence of cardiac disease (control dogs) were retrospectively reviewed. From right lateral thoracic radiographic images, the lengths of the cardiac short and long axes and the manubrium were measured and cardiac sphericity indices (CSIs), MHSs, and vertebral heart scores were determined. Dogs were grouped on the basis of whether they did or did not have cardiac disease (case dogs vs control dogs), breed size (large-breed dogs vs small-breed dogs), and whether cardiac disease affected the right side of the heart (right-sided cardiac disease) or the left side of heart (left-sided cardiac disease). Results were compared across groups.

RESULTS

The mean CSI was greatest in case dogs with right-sided cardiac disease, compared with other groups. In dogs of the present study, a combination of high short-, long-, and overall-MHSs was more suggestive of left-sided cardiac disease, whereas a high short-MHS without high long- and overall-MHSs was more suggestive of right-sided cardiac disease.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that MHSs could be useful, objective values to help assess dogs for potential heart disease, and we recommend that MHSs be added to the diagnostic tools used by veterinarians when screening for heart disease in dogs.

Companion animals likely do not spread COVID-19 but may get infected themselves

Coronavirus disease 2019 (COVID-19) is a highly contagious infectious disease caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). From the epidemiological data, the picture emerges that the more severe etiopathologies among COVID-19 patients are found in elderly people. The risk of death due to COVID-19 increases exponentially with age. Eight out of 10 COVID-19 related deaths occur in people older than 65 years of age. Older patients with comorbid conditions such as hypertension, heart failure, diabetes mellitus, asthma, chronic obstructive pulmonary disease, and cancer have a much higher case fatality rate. Governments and public health authorities all over the world have realized that protections of vulnerable older adults should be a priority during the COVID-19 pandemic. COVID-19 is a zoonotic disease. The SARS-CoV-2 virus was originally transmitted likely from a bat or a pangolin to humans. Recent evidence suggests that SARS-CoV-2, similar to other coronaviruses, can infect several species of animals, including companion animals such as dogs, cats, and ferrets although their viral loads remain low. While the main source of infection transmission therefore is human to human, there are a few rare cases of pets contracting the infection from a SARS-CoV-2-infected human. Although there is no evidence that pets actively transmit SARS-CoV-2 via animal-to-human transmission, senior pet ownership potentially may pose a small risk to older adults by (1) potentially enabling animal-to-human transmission of SARS-CoV-2 in the most vulnerable population and (2) by increasing the exposition risk for the elderly due to the necessity to care for the pet and, in the case of dogs, to take them outside the house several times per day. In this overview, the available evidence on SARS-CoV-2 infection in pets is considered and the potential for spread of COVID-19 from companion animals to older individuals and the importance of prevention are discussed.

Radiographic vertebral left atrial size: A reference interval study in healthy adult dogs

Thoracic radiography is a useful technique for the evaluation of cardiac dimensions, especially when echocardiography is not possible. The vertebral left atrial size (VLAS) has recently been proposed as a new radiographic method for quantifying left atrial dimensions in dogs. The aims of this retrospective, reference interval, observational study were to describe values for VLAS in a group of healthy adult dogs and to compare intraobserver and interobserver agreement for VLAS versus vertebral heart score (VHS) methods. Thoracic radiographs of 80 healthy adult dogs were evaluated. Normal left atrial size was determined based on an echocardiographic left atrial-to-aorta ratio < 1.6. The VLAS and vertebral heart score values were measured from right lateral radiographs. The correlations between VLAS, the vertebral heart score, and the left atrial-to-aorta ratio were evaluated. The effects of body weight, sex, and age were also tested using regression analyses. The median value of VLAS were 1.9, with a reference interval of 1.4-2.2. A positive correlation was found between VLAS and vertebral heart score values (r = 0.53; P < .0001). No effect of body weight, sex, and age on VLAS was detected. Excellent intraobserver and interobserver agreements were found for both VLAS and vertebral heart score methods (intraclass correlation coefficients ≥ 0.91). Findings from this sample of healthy dogs indicated that VLAS is a repeatable radiographic method for quantifying left atrial size. Further studies are warranted to evaluate this measure in clinically affected dogs.

Retrospective quantitative assessment of liver size by measurement of radiographic liver area in small-breed dogs

OBJECTIVE

To determine the feasibility of radiographic measurement of liver area in small-breed dogs and to assess correlations between CT liver volume measurements (reference standard) and radiographic liver size measurements.

ANIMALS

107 small-breed dogs (body weight, ≤ 10 kg) that had previously undergone orthogonal thoracic and abdominal radiography and abdominal CT.

PROCEDURES

In a retrospective study design, dogs were allocated to groups (normal liver [n = 36], microhepatia [34], and hepatomegaly [37]) on the basis of radiographic liver size and clinicopathologic findings. Radiographic liver area (RLA) was automatically calculated from archived radiographic images by free-hand outlining of the liver margins by use of DICOM viewer software, and other standard radiographic measurements were performed. Liver volume was measured on CT images. Intraoperator repeatability of RLA and CT measurements was assessed (duplicate measurements 2 weeks apart). To control for various breed conformations, radiographic values were normalized to body weight and T11 area.

RESULTS

Mean ± SD ratios of RLA to T11 area and RLA to body weight for dogs with normal livers were 32.7 ± 6.2 and 7.0 ± 1.4, respectively. Excellent intraobserver agreement was observed in RLA measurements within groups (intraclass correlation coefficients, 0.861 to 0.989), and RLA measurements had the highest correlation with CT liver volume measurements (r = 0.94) of all radiographic measurements.

CONCLUSIONS AND CLINICAL RELEVANCE

Findings indicated that RLA measurement in small-breed dogs with or without liver disease was useful and accurate for estimation of liver size, compared with CT measurement, and might be particularly useful for monitoring of changes in liver size.

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.

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.

Serial measurements of cardiac troponin I in heart failure secondary to canine mitral valve disease

Serial measurements of cardiac troponin I (cTnI) levels are considered to be better predictors of cardiac death than single-time-point analyses in human medicine. We hypothesised that cTnI levels could reflect the severity of myxomatous mitral valve disease (MMVD), and that serial changes in the cTnI level had a prognostic value in dogs with congestive heart failure (CHF) secondary to MMVD. Seventy-six dogs were initially enrolled and classified by the American College of Veterinary Internal Medicine (ACVIM) staging system. The single-timepoint cTnI concentration in these dogs significantly increased with the ACVIM stage. Twenty-seven dogs with CHF subsequently underwent serial measurement of cTnI levels, and the results showed that those who demonstrated a decrease in cTnI levels from the first to the third visit exhibited a higher risk of cardiac death than did those without such changes (P=0.012). We suspect that the downward trend in cTnI levels may be affected by medical treatment for CHF. In conclusion, although cTnI levels could reflect the severity of MMVD to a certain extent, the serial changes may be affected by medical treatment. Therefore, caution should be exercised when cTnI is used for assessment of the prognosis of CHF secondary to MMVD in dogs.

Correlação entre os achados radiográficos e ecocardiográficos sugestivos de aumento cardíaco em cães: 104 casos

RESUMO Radiografias torácicas e ecocardiogramas de 104 caninos foram avaliados e correlacionados quanto ao aumento das câmaras cardíacas. Os achados radiográficos foram correlacionados estatisticamente a fim de se estabelecer a acurácia do exame radiográfico na detecção do aumento cardíaco em comparação ao ecocardiográfico - padrão-ouro não invasivo. A correlação entre os achados radiográficos indicativos de aumento cardíaco e os índices ecocardiográficos mostrou-se fraca, significativa somente para VHS versus relação átrio esquerdo/aorta (r=0,3136), eixo curto versus relação átrio esquerdo/aorta (r=0,3813) e eixo curto versus velocidade da onda E (r=0,2021). A acurácia da radiografia na determinação subjetiva de aumento das câmaras cardíacas foi razoável, variando entre 72,1% e 80,8%. Em contrapartida, o VHS apresentou baixa acurácia (50,9%) na detecção de cardiomegalia.

Development and assessment of a novel precordial lead system for accurate detection of right atrial and ventricular depolarization in dogs with various thoracic conformations

OBJECTIVE

To assess recording accuracy of right atrial and ventricular depolarization during 12-lead ECG when precordial lead V₁ was positioned at each of 5 locations on the thorax of dogs with various thoracic conformations.

ANIMALS

60 healthy client-owned dogs.

PROCEDURES

20 dogs were allocated to each of 3 groups (brachymorphic, mesomorphic, or dolichomorphic) on the basis of thoracic conformation. Each dog remained unsedated and was positioned in right lateral recumbency for a series of five 12-lead surface ECGs, with V₁ located adjacent to the sternum in the fifth intercostal space (ICS; control), at the costochondral junction (CCJ) of the right first ICS (1st-R), at the CCJ of the right third ICS, at the right third ICS where the thorax was the widest, and at the CCJ of the left first ICS. Electrocardiographic variables were compared among the 5 ECG tracings.

RESULTS

When V₁ was at the control location, the P wave was positive for all dogs; however, consistent recording of right atrial and ventricular depolarization (ie, R wave-to-S wave ratio [R/S] < 1) occurred more frequently for brachymorphic dogs (16/20) than for dolichomorphic (7/20) and mesomorphic (6/20) dogs. When V₁ was at the 1st-R location, the P wave was negative for most dogs, and R/S was < 1 for the majority of dogs in the brachymorphic (19/20), mesomorphic (17/20), and dolichomorphic (16/20) groups. The median R/S for V₁ at the 1st-R location was significantly lower than that for the other 4 V₁ locations.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that placement of V₁ at the 1st-R location provided correct evaluation of right atrial and ventricular depolarization in most dogs regardless of thoracic conformation.

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.

Electrocardiography-gated cardiac CT angiography can differentiate brachycephalic dogs with and without pulmonary valve stenosis and findings differ from transthoracic echocardiography

Pulmonary valve stenosis (PS) is one of the most commonly diagnosed congenital heart defects in dogs. Currently, transthoracic echocardiography (TTE) is the standard modality used to evaluate PS. Image acquisition by TTE can be challenging in some brachycephalic breeds of dogs. The use of echocardiographic-gated CT angiography (ECG-gated CTA) in veterinary medicine is limited. This retrospective method comparison study investigated right and left ventricular outflow diameters by sedated ECG-gated CTA and unsedated TTE in 14 brachycephalic dogs with PS and 12 brachycephalic dogs without PS. Measurements of ventricular outflow structures were made in early systole and end diastole for both modalities and then compared for significance between systolic and diastolic phases, as well as between the two modalities. Ratios of the pulmonary trunk diameter to the aorta at different locations (aortic valve, aortic annulus, and ascending aorta) and in different planes (transverse, sagittal) were compared between dogs with PS and without PS, as well as within dogs, by both TTE and ECG-gated CTA. Transthoracic echocardiography and ECG-gated CTA both detected significantly greater pulmonary trunk to aorta ratios in dogs with PS at all aortic locations (P < 0.05). Pulmonary valve to aortic valve ratios were significantly smaller in dogs with PS (P < 0.05). Pulmonary trunk to aorta and pulmonary valve to aorta ratios were achieved with good anatomic detail using ECG-gated CTA. Ratios of the pulmonary trunk and pulmonary valve relative to the aorta may be useful to evaluate for PS using a modality that is underutilized for cardiac assessment.