Echocardiographic variables in healthy North American Salukis

M-Mode Echocardiography in Canine Veterinary Practice: A Comprehensive Review of Left Ventricular Measurements in 44 Different Dog Breeds

This review article focuses on the use of canine M-mode in veterinary medicine, specifically in assessing the left ventricle measurements in several breeds. It traces the historical development of echocardiography techniques, including A-mode, B-mode, and motion mode (M-mode), which provide accurate unidimensional records of cardiac structures. This article highlights the significance of M-mode measurements in diagnosing stage B2 of MMVD, where left ventricular end-diastolic internal diameter corrected with body weight (LVIDdN) is essential for identifying cardiac enlargement. It also explains the role of M-mode in diagnosing DCM, outlining criteria such as left ventricular dilatation. The authors emphasize the importance of breed-specific reference values for echocardiographic measurements due to variations in somatotype among dogs. This review provides a comprehensive table summarizing M-mode measurements of the left ventricle for 44 different dog breeds, including interventricular septum thickness, left ventricular internal diameter, and left ventricular posterior wall thickness during systole and diastole. This review's methodology involves compiling data from various scientific literature sources, providing an extensive tabular representation of M-mode measurements for different breeds, ages, and sexes. Overall, this review highlights the critical role of M-mode echocardiography in diagnosing and managing cardiac diseases in dogs, underscores the importance of breed-specific reference values, and presents a comprehensive summary of M-mode measurements for various dog breeds, aiding both clinicians and researchers.

A multicenter, retrospective study of cardiac disease in Borzoi dogs

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

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.

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.

Screening for dilated cardiomyopathy in dogs

BACKGROUND

Dilated cardiomyopathy (DCM) is the most common cardiac disease in large breed dogs. The disease can start with arrhythmias or with systolic dysfunction of the myocardium.

OBJECTIVE

To describe screening methods for DCM in various breeds and provide a new, modified staging system.

RECOMMENDATIONS

Screening for occult DCM should start at three years of age and use Holter monitoring in Boxers and Dobermans and might be useful also in other breeds. Single ventricular premature complexes (VPCs) can be detected in many healthy dogs, but healthy animals typically have <50 VPCs in 24 h and demonstrate minimal complexity most often occurring only as single ectopic beats. In general, >100 VPCs in 24 h was recommended as the cut-off value for establishing a diagnosis of DCM. However, there are breed-specific recommendations related to Holter recording diagnosis of DCM in Dobermans and Boxers. Yearly screening over the life of a dog is recommended, as a one-time screening is not sufficient to rule out the future development of DCM. Several echocardiographic methods such as M-mode derived measurements, the measurement of the left ventricular (LV) volume by Simpson's method of discs (SMOD), and E-point to septal separation (EPSS) are recommended for screening purposes. The value of additional tests such as cardiac biomarkers (troponin I and N-terminal pro-B-type natriuretic peptide) as well as a 5-min resting electrocardiogram (ECG) or newer echocardiographic methods such as strain measurements is discussed.

CONCLUSION

This review suggests some guidelines for screening for DCM in various breeds.

An echocardiographic study of breed-specific reference ranges in healthy French Bulldogs

Echocardiography is a standard diagnostic tool for assessment of cardiac functions and cardiovascular diseases in dogs, however published echocardiographic measurements have varied widely based on dog breeds. The objective of this prospective reference interval study was to provide breed-specific echocardiographic values for healthy French Bulldogs. A total of 42 healthy French Bulldogs of both sexes (23 females and 19 males) were sampled. Furthermore, measurements for a control group (n = 16) were also conducted in four other dog breeds (Cocker Spaniel [n = 2], Cavalier King Charles Spaniel [n = 4], Terrier [n = 5], and Crossbreed [n = 5]). Standard M-mode, two-dimensional (2D), pulse wave (PW) Doppler, and tissue Doppler imaging (TDI) echocardiographic measurements were obtained from healthy French Bulldogs. The M-mode echocardiographic data obtained from French Bulldogs were compared to the data obtained from the control group. The left ventricular internal dimension at end-diastole (LVIDd; cm)/body surface area (BSA) (m² ) ratio for the study group was 3.35/0.53 = 6.32. Left ventricular measurements for French bulldogs and internal dimension at end-systole (21.23 ± 3.50 mm) and at end-diastole (33.50 ± 4.12 mm) were found to be significantly higher (P < .001) compared to control group values (left ventricular internal dimension at end-systole [LVIDs]; 17.46 ± 2.85 mm, LVIDd; 27.16 ± 4.20 mm, respectively). A significantly positive correlation in the French Bulldog group was noted between body weight and M-mode measurements (EPSS, IVSd, IVSs, LVIDd, LVIDs, and LVPWd). French bulldogs had a greater systolic and diastolic left ventricular volume than the control group. As a result, values reported in this study could be used as specific reference ranges in French Bulldogs.

Two-dimensional echocardiographic estimates of left ventricular volumes obtained in different views in dogs provide similar measurements but are not interchangeable

INTRODUCTION

Little information exists regarding the interchangeability of left ventricular volume estimates using a monoplane Simpson's Method of Discs on images obtained from the left apical four-chamber and right parasternal long axis four-chamber views. We examined if volume estimates obtained from these views were interchangeable.

ANIMALS

A total of 224 dogs: 86 healthy, 96 with mitral valve disease, 42 with various cardiac pathologies.

MATERIALS AND METHODS

Investigators obtained right parasternal long-axis and left apical four-chamber views from each dog and used manufacturer-supplied software to estimate left ventricular volumes in diastole and systole using Simpson's Method of Discs. Estimates based on linear measurements (diameter cubed, 0.67∗diameter cubed, and Teichholz) were also calculated. Reproducibility for each view, and agreement between the estimates obtained with each view, and those calculated from linear dimensions, were examined using Limits of Agreement. Reference intervals for volumes indexed to bodyweight and body surface area were calculated.

RESULTS

Neither method proved very reproducible. Although no bias was detected, the agreement between volumes indexed to bodyweight and body surface area was insufficient to recommend interchangeability. Estimates based on Teichholz and diameter cubed methods overestimated volumes; however, those based on 0.67∗diameter cubed performed reasonably.

CONCLUSIONS

Monoplane volume estimates from the left apical and right parasternal long axis four-chamber views are similar but not interchangeable. Clinicians can perform crude estimates of left ventricular volume using the equation 0.67∗diameter cubed.

Cardiovascular Clinical Assessment in Greyster Dogs in Bikejöring Training

Simple Summary

Regular intense exercise is known to induce cardiac hypertrophy in some dogs engaged in different physical activities, but the cardiovascular response in dogs that routinely carry out aerobic exercise in the form of bikejöring (a form of dryland mushing) is unknown. The pre- and post-competition clinical examinations usually carried out in canine athletes include an electrocardiogram due to its diagnostic value, but some cardiac structural disturbances may go unnoticed at rest, especially in the early stages of disease. In our study, changes in systolic, mean and pulse pressure were detected after exercise, while diastolic blood pressure remained stable. Numerous changes in echocardiographic variables (LVFS-left ventricle fractional shortening, LVEF-left ventricle ejection fraction, EPSS-E-point to septal separation, CO-cardiac output, CI-cardiac index, PWd-posterior wall thickness at end-diastole and major/minor axis ratio) were also found. No association was found between the sex of the animals and the differences in the data. Our findings lead us to recommend theLVF introduction of echocardiograms for the clinical evaluation of canine athletes competing in this form of mushing. Furthermore, by including echocardiograms in clinical examinations during physical training, knowledge of the individual cardiovascular response after exercise can be improved.

Abstract

Bikejöring is a type of dryland mushing requiring high-intensity aerobic effort, with speed peaks close to 42 km/h. Greysters (crosses between the German Shorthaired Pointer and the Greyhound) often participate in such events and perform well. The objective of this comparative study was to evaluate the clinical use of non-invasive methods in assessing the cardiovascular health of 22 Greyster dogs in physical training, by determining the differences between different cardiovascular parameters before and after physical training. Blood pressure, heart rate and echocardiographic results were compared. The mean age of the dogs was 4.4 years ± 1.8% and 54.5% were female. All participating dogs regularly participated in bikejöring. Post-exercise increases were observed in systolic blood pressure (SBP), mean arterial pressure (MBP) and pulse pressure (SBPD), with diastolic blood pressure (DBP) remaining stable. Changes of clinical interest were observed in numerous echocardiographic variables such as left ventricle fractional shortening (LVFS), left ventricule ejection fraction (LVEF), E-point to septal separation (EPSS), cardiac output (CO), cardiac index (CI), posterior wall thickness at end-diastole (PWd) and major/minor axis ratio (MA/ma), including a decrease in the shortening fraction and an increase in EPSS after exercise. These clinical findings were observed in both males and females; they do not appear to be associated with dilated cardiomyopathy, but rather with a cardiovascular response to physical training. This study derives from the real interest of clinical veterinarians who care for highly trained canine athletes. It contributes to an increase in knowledge of the different cardiac adaptations of such dogs after intense exercise and serves to differentiate these from pathologic conditions.

Assessment of Longitudinal Left Ventricle Deformation by 2-Dimensional Speckle Tracking Echocardiography Obtained from Different Views in Cats

Two-dimensional speckle tracking echocardiography (STE) is a novel, angle-independent imaging technique useful to assess myocardial function by strain and strain rate analysis in human and veterinary medicine. Commonly, the left apical four-chamber (LAP4Ch) view is used to assess left ventricular (LV) longitudinal deformation in dogs and cats. However, the right parasternal four-chamber (RP4Ch) view is often more easily obtained than the LAP4Ch view in cats. No studies exist comparing longitudinal strain and strain rate values using STE from different echocardiographic views in cats. Therefore, we examined the agreement between RP4Ch and LAP4Ch for assessment of LV longitudinal strain and strain rate in cats. We acquired 2D echocardiographic cineloops from RP4Ch and LAP4Ch views and analyzed LV longitudinal strain and strain rate in 50 cats (31 healthy cats and 19 cats with different disease states) using Xstrain^TM software. Peak systolic strain and strain rate values of endocardial and epicardial border were used for the analysis. The two echocardiographic views were compared using limits-of-agreement analyses and intra-observer measurement variability was assessed. We could obtain longitudinal strain and strain rate from the RP4Ch view in all cats. Strain, but not strain rate, had good intra-observer measurement variability (<10% vs. <20%). However, only endocardial strain values obtained with the two views agreed sufficiently to be used interchangeably (95% limits of agreement: −3.28, 2.58). Epicardial strain/strain rate and endocardial strain rate values did not agree sufficiently to be used interchangeably (95% limits of agreement: −11.58, 9.19; −2.28, 1.74; −1.41, 1.36, respectively). Our study suggests that RP4Ch view was feasible for assessment of the LV longitudinal deformation analysis by STE in cats, but only endocardial longitudinal strain values obtained from the two different views were interchangeable.