Echocardiography and conventional Doppler examination in clinically healthy adult Cavalier King Charles Spaniels: Effect of body weight,age, and gender,and establishment of reference intervals

ObjectivesThe objectives of this study were (1) to assess the potential effect of body weight (BW), age, and gender on the most commonly used echocardiographic and conventional Doppler variables in a large population of healthy Cavalier King Charles Spaniels (CKCS), and (2) to establish the corresponding reference intervals (RI).Animals134 healthy adult CKCS.MethodsUltrasound examinations were performed by trained observers in awake dogs. M-mode variables included left ventricular (LV) end-diastolic and end-systolic diameters, LV free wall and interventricular septal thicknesses at end-diastole and end-systole, and LV fractional shortening (FS%). The left atrium (LA) and aortic (Ao) diameters were measured using a 2D method, and the LA/Ao was calculated. Pulsed-wave Doppler variables included peak systolic aortic and pulmonary flow velocities, mitral E and A waves, and E/A ratio. Effects of BW, age, and gender on these 15 variables were tested using a general linear model, and RIs were determined by applying the statistical procedures recommended by the Clinical and Laboratory Standards Institute.ResultsA significant BW effect was observed for all variables, except LA/Ao, FS%, and mitral E/A ratio. A significant but negligible effect of gender and age was also observed for 5/15 and 4/15 of the tested variables, respectively. Only the BW effect on M-mode variables was considered as clinically relevant and the corresponding regression-based RIs were calculated.ConclusionsBody weight should be taken into account when interpreting echocardiographic values in CKCS, except for LA/Ao, FS%, and mitral E/A ratio.     

Echocardiographic ratio indices in overtly healthy Boxer dogs screened for heart disease

BACKGROUND: Boxer dogs are routinely screened by echocardiography to exclude congenital and acquired heart disease. Individuals of a given breed may span a large range of body sizes, potentially invalidating linear regression of M-mode measurements against body weight. Echocardiographic ratio indices (ERIs) provide a novel method of characterizing echocardiographic differences between Boxers and other dog breeds. HYPOTHESIS: ERIs obtained from overtly healthy Boxer dogs presented for cardiac screening will be different from ERIs established for normal non-Boxer dogs, and those differences will be unrelated to aortic velocity or systolic blood pressure. ANIMALS: Eighty-one Boxers with no outward clinical signs of heart disease were studied. METHODS: All dogs were examined by 2-dimensional, M-mode, and Doppler echocardiography. M-mode measurements were used to perform ERI calculations, and the indices in Boxers were compared between Boxers with varying severity of arrhythmia and those of normal non-Boxer dogs. RESULTS: Differences in weight-based ERIs, which reflect increased thickness of the left ventricular free wall (LVW) and interventricular septum (IVS) and smaller aortic size, were found in overtly healthy Boxer dogs compared with normal non-Boxer dogs. ERIs of left atrial and LV cavity size in overtly healthy Boxers were not significantly different from those of non-Boxer dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: Boxer dogs may have an increased relative thickness of the LVW and IVS that is independent of aortic size, aortic velocity, or arterial blood pressure, and this morphology should be taken into consideration when screening Boxers by echocardiography.     

Changes in linear dimensions of the heart, relative to body weight, as measured by M-mode echocardiography in growing dogs.

The growth of the heart, relative to body weight, was measured by M-mode echocardiography in dogs during the first year of life. Echocardiographic measurements were obtained from 16 English Pointers at 1, 2, 4, and 8 weeks of age and at 3, 6, 9, and 12 months of age. Left atrial (LA), aortic (AO), left and right ventricular internal dimensions, interventricular septal and left ventricular wall thickness measurements increased in curvilinear fashion relative to increasing body weight. Least-squares regression analysis, performed on logarithmically transformed data, was used to develop power-law equations describing the relationship of echocardiographic measurements to body weight. Linear dimensions of the LA, AO, left and right ventricular internal dimensions and interventricular septal and left ventricular wall thickness changed proportionally to slightly differing exponential powers of body weight (BW), varying from 0.31 to 0.45 (BW0.31 to BW0.45). Fractional shortening and the LA to AO ratio decreased slightly, but significantly, as body weight increased. Indexing echocardiographic measurements to BW1/3 was more appropriate than indexing such measures linearly to body weight, offering a practical method for developing accurate normative graphs or tables for M-mode echocardiographic dimensions in growing dogs.     

Prognostic value of selected one-, two- and three-dimensional and Doppler echocardiographic methods to assess severity in dogs with myxomatous mitral valve disease

IntroductionAlthough challenging, predicting outcomes in dogs with myxomatous mitral valve disease (MMVD) is of importance to owners and veterinarians. Our aim was to compare the prognostic value of selected one-, two-, and three-dimensional and Doppler echocardiographic methods to predict cardiac-related and all-cause mortality in MMVD dogs. We hypothesize that three-dimensional methods would better predict prognosis than one- and two-dimensional methods.AnimalsOne-hundred thirty-eight privately-owned dogs with MMVD.Materials and methodsCox proportional Hazard analyses and Kaplan–Meier curves were used to investigate the predictive value of 14 variables; left atrial (LA) volume indexed to body weight (BW) measured by real-time three-dimensional echocardiography (RT3DE) and calculated using Simpson's modified method of discs (SMOD) and the area-length method; LA diameter in short-axis and long-axis to aortic in short-axis ratio, effective regurgitant orifice area indexed to body surface area measured in RT3DE en face view and calculated using four-chamber (4Ch) and two-chamber views alone or in combination; percentage increase in left ventricular end-diastolic and systolic internal diameters; fractional shortening; E wave velocity; regurgitant jet area/LA area.ResultsAll 14 variables were significantly predictive of cardiac-related mortality, and 11 were predictive of all-cause mortality. The prognosis was best predicted by LA volume/BW estimated by SMOD or RT3DE, consistently showing the highest predictive value in all analyses.ConclusionsLeft atrial volume calculated by SMOD showed a similar predictive value compared to RT3DE. Performing SMOD from apical 4Ch images should be considered an alternative to RT3DE for echocardiographic examinations where prognostication of disease outcome is sought.     

Two-dimensional,long-axis echocardiographic ratios for assessment of left atrial and ventricular size in dogs

Introduction

Left ventricular (LV) and left atrial (LA) enlargement affect management and outcome of dogs with cardiac disease. Short-axis, two-dimensional echocardiographic (2DE) images, indexed to the aorta (Ao), are frequently used to identify cardiomegaly. Long-axis images offer complementary views of the left heart.

An echocardiographic study of healthy Border Collies with normal reference ranges for the breed

ObjectivesThe objectives of this study were to obtain standard echocardiographic measurements from healthy Border Collies and to compare these measurements to those previously reported for a general population of dogs.AnimalsStandard echocardiographic data were obtained from twenty apparently healthy Border Collie dogs. These data (n = 20) were compared to data obtained from a general population of healthy dogs (n = 69).MethodsBorder Collies were deemed healthy based on normal history, physical examination, complete blood count, serum biochemical profile, electrocardiogram, and blood pressure, with no evidence of congenital or acquired heart disease on echocardiographic examination. Standard two dimensional, M-mode, and Doppler echocardiographic measurements were obtained and normal ranges determined. The data were compared to data previously obtained at our hospital from a general population of normal dogs.ResultsTwo dimensional, M-mode, and Doppler reference ranges for healthy Border Collies are presented in tabular form. Comparison of the weight adjusted M-mode echocardiographic means from Border Collies to those from the general population of dogs showed Border Collies to have larger left ventricular systolic and diastolic dimensions, smaller interventricular septal thickness, and lower fractional shortening.ConclusionsThere are differences in some echocardiographic parameters between healthy Border Collies and the general dog population, and the echocardiographic reference ranges provided in this study should be used as breed specific reference values for Border Collies.     

LEFT ATRIAL TO AORTIC ROOT INDICES USING TWO-DIMENSIONAL AND M-MODE ECHOCARDIOGRAPHY IN CAVALIER KING CHARLES SPANIELS WITH AND WITHOUT LEFT ATRIAL ENLARGEMENT

Two-dimensional (2-D) echocardiographic measurement of the left atrium (LA) has the potential to be more accurate than the standard M-mode method, because the LA body can be measured. We evaluated a 2-D method for measuring LA and aorta (AO) in a right parasternal short-axis view and compared it to the M-mode method. An index for LA size (LA/AO) was calculated in 166 cavalier King Charles spaniels, 56 normal and 110 dogs with mitral regurgitation (MR) of varying degrees secondary to chronic valvular disease. In normal dogs, the AO-2-D and LA/AO-2-D did not correlate to body weight (BW) or BW2; whereas, all M-mode values and the LA-2-D were significantly (p < .05) related to both BW parameters. In normal dogs, there was no difference between M-mode and 2-D indices. For all dogs (normal and dogs with MR) there was an 11% bias between the M-mode and 2-D index with the LA/AO-2-D being higher than the LA/AO-M. The association between the mean and the difference of the indices demonstrated a quadratic relationship. Dogs with a mean LA/AO of 2.0-2.5 showed the largest difference between the two indices. Small values for the 2-D coefficients of variation for respiration and stage of diastole were found; 3.4 and 3.1%, respectively. The 2-D index is more sensitive to LA enlargement than the M-mode index.     

Evaluation of four 2-dimensional echocardiographic methods of assessing left atrial size in dogs

Two-dimensional (2D) echocardiography is the cornerstone of noninvasive evaluation of the cardiac patient, and often involves estimating left atrial (LA) size. However, 2D echocardiographic methods of estimating LA size have been inadequately described, and most reference intervals are based on M-mode echocardiographic measurements. We determined reference intervals for 4 different 2D echocardiographic methods of estimating LA size in adult (> or =9-month-old) dogs without cardiovascular disease. Thirty-six dogs, placed in right lateral recumbency, were examined by 2D echocardiography. The left atrium was measured at specific time points in the cardiac cycle. Measurement methods were LA diameter in short axis, LA diameter in long axis, LA circumference in short axis, and LA cross-sectional area in short axis. Comparisons of these LA dimensions to appropriate aortic dimensions provided body weight-independent estimates of LA size. We found strong associations of LA dimensions with body weight (r2 = .76-.88). Comparable body weight-independent 2D echocardiographic estimates of LA size in short axis exceeded historical M-mode reference intervals. These data provide echocardiographers with reference intervals for 2D echocardiographic estimates of LA size in adult dogs.     

Tricuspid annular plane systolic excursion-to-aortic ratio provides a bodyweight-independent measure of right ventricular systolic function in dogs

Objectives

To evaluate whether tricuspid annular plane systolic excursion (TAPSE) can be normalized to aortic valve (Ao) measurements in dogs. To determine TAPSE:Ao reference intervals for healthy dogs and examine diagnostic performance of TAPSE:Ao in dogs with pulmonary hypertension (PH).

Arrhythmogenic right ventricular cardiomyopathy in Bulldogs: Evaluation of clinical and histopathologic features,progression, and outcome in 71 dogs (2004–2016)

ObjectivesThis study aimed to characterize the clinical and histopathological features of arrhythmogenic right ventricular cardiomyopathy (ARVC) in English Bulldogs, American Bulldogs, and Bulldog-type mixed breed dogs and assess affected Bulldogs for a striatin gene mutation previously reported in Boxers with ARVC.AnimalsSeventy-one Bulldogs fit the inclusion criteria. Genetic analysis was performed on five dogs. Cardiac post-mortem evaluations were performed on two dogs.MethodsMedical records from a single veterinary cardiology group (CVCA) were retrospectively evaluated. Tissue and blood samples were submitted for histopathological analysis and genetic testing in select patients.ResultsPresenting complaints included syncope (38%), arrhythmia (81.7%), or murmur (34.2%) documented on examination. On presentation, congestive heart failure (CHF) was diagnosed in 22 (31%) dogs, and 58 (81.7%) had ventricular arrhythmias. On bivariable analyses, the two-dimensional (2D) left atrial-to-aortic root ratio (LA:Ao) was the only prognostic variable significantly associated with survival time. Dogs with 2D LA:Ao below the mean (1.41) had longer median survival to all-cause mortality (12 months; 95% confidence interval [CI] six–15 months) than those with 2D LA:Ao above the mean (four months; 95% CI two–six months; p=0.0384). Most dogs (54%) died from cardiac disease, with 42.1% experiencing sudden death. The median time from diagnosis to cardiac death was four months.ConclusionsArrhythmogenic right ventricular cardiomyopathy affects Bulldogs with both arrhythmogenic and dilated-type phenotypes. Despite variable arrhythmia severity and predominantly right-sided involvement in many dogs, an increase in left atrial size was the only significant predictor of mortality in this sample of dogs.     

M-MODE ECHOCARDIOGRAPHIC PARAMETERS AND INDICES IN THE NORMAL GERMAN SHEPHERD DOG

M-mode echocardiographic measurements were made from 50 healthy German Shepherd dogs (30 males and 20 females). The dogs were awake and unsedated, in right lateral recumbent position. The following parameters were measured on the echocardiographic images: interventricular septal thickness at end-diastole (IVSd), interventricular septal thickness at end-systole (IVSs), left ventricular internal dimension at end-diastole (LVIDd), left ventricular internal dimension at end-systole (LVIDs), left ventricular posterior wall thickness at end-diastole (LVPWd), left ventricular posterior wall thickness at end-systole (LVPWs), left atrial dimension (LAD), aortic root dimension (AOD), left atrial to aortic root ratio (LAD/AOD), right ventricular internal dimension at end-diastole (RVID), amplitude of mitral valve excursion (DE amplitude), velocity of mitral valve opening (D-E slope), and velocity of mitral valve closure (E-F slope). Fractional shortening (FS) was also calculated. The effect of gender and age on each echocardiographic parameter was analyzed and the relationship between body weight (BW) and each parameter was also investigated. There was a significant relationship between gender and LVPW in systole and diastole and FS. Significant association was also found between BW and IVS, LVID, and LVPW in systole and diastole, FS, LAD, AOD, RVID, DE amplitude, and D-E slope of the mitral valve.     

M-mode echocardiographic ratio indices in normal dogs, cats, and horses: a novel quantitative method

A novel method for quantitative echocardiographic interpretations is introduced based on the calculation of ratio indices in which each raw M-mode measurement is divided by the aortic root dimension (Ao). "Aorta-based" indices were calculated with the animal's measured aortic root dimension (Ao(m)) as the length standard. Conversely, "weight-based" indices employed an idealized estimate of aortic dimension (Ao(w)) with a weighted least squares linear regression against the cube root of body weight (Ao(w) = kW(1/3)). Use of these indices circumvented undesirable statistical characteristics inherent in linear regression of echocardiographic dimensions against body weight and, to a lesser extent, body surface area. Compared with the regressions, ratio indices resulted in substantial refinement of the predictive range for each M-mode measurement in dogs, particularly with decreasing body size. Weight-based indices outperformed aorta-based indices in this regard. To refine the predictive range, neither type of index was clearly advantageous in cats compared with the simple average method typically employed for that species. Several of the raw M-mode measurements, however, were correlated with body weight in cats and horses, indicating the need for an appropriate correction for body size in these species. The ratio index method was suitable for this purpose. Summary statistics derived from normal dogs (n = 53), cats (n = 32), and horses (n = 17) are presented for each index, including novel clinical indices calculated from area ratios. The latter were designed to represent body size-adjusted lett ventricular stroke area (ie, volume overload) and myocardial wall area (ie, hypertrophy).     

Echocardiographic parameters in healthy young adult Sphynx cats

The objective of this retrospective study is to determine normal reference values for 2-Dimension (2D) and Motion-mode (M-mode) echocardiographic parameters in nonsedated healthy young adult Sphynx cats and to compare them to those of the domestic shorthair (DSH). 131 Sphynx cats underwent cardiac screening prior to breeding. The control group consisted of 30 healthy adult domestic cats. A complete cardiac ultrasound was performed on all cats using right parasternal long and short axis views. There were few echocardiographic parameters in the Sphynx that differed from those of the healthy DSH. Only the left atrial (LA) dimension in 2D and M-mode, the left atrial/aortic (LA/Ao) ratio and the internal dimension of the left ventricle in systole (LVIDs) measured with M-mode were different. In conclusion, although the heart of Sphynx cat can often have a particular 2-D echocardiographic appearance, the M-mode cardiac dimensions are similar to those of the DSH.     

Echocardiographic parameters and indices in 23 healthy Maltese dogs

BackgroundEchocardiography is a primary tool used by veterinarians to evaluate heart diseases. In recent years, various studies have targeted standard echocardiographic values for different breeds. Reference data are currently lacking in Maltese dogs and it is important to fill this gap as this breed is predisposed to myxomatous mitral valve disease, which is a volume overload disease.ObjectivesTo establish the normal echocardiographic parameters for Maltese dogs.MethodsIn total, 23 healthy Maltese dogs were involved in this study. Blood pressure measurements, thoracic radiography, and complete transthoracic echocardiography were performed. The effects of body weight, age and sex were evaluated, and the correlations between weight and linear and volumetric dimensions were calculated by regression analysis.ResultsThe mean vertebral heart size was 9.1 ± 0.4. Aside from the ejection fraction, fractional shortening, and the left atrial to aorta root ratio, all the other echocardiographic parameters were significantly correlated with weight.ConclusionThis study describes normal echocardiographic parameters that may be useful in the echocardiographic evaluation of Maltese dogs.     

Measurement of M-mode echocardiographic parameters in healthy adult Maine Coon cats

OBJECTIVE: To determine reference values for M-mode echocardiographic parameters in nonsedated healthy adult Maine Coon cats and compare those values with data reported for nonsedated healthy adult domestic cats. DESIGN: Prospective study. ANIMALS: 105 healthy adult Maine Coon cats. PROCEDURE: Over a 3-year period, M-mode echocardiographic examinations (involving a standard right parasternal transthoracic technique) were performed on Maine Coon cats as part of prebreeding evaluations; values of M-mode parameters in healthy individuals were collected, and mean values were calculated for comparison with those reported for healthy adult domestic cats. RESULTS: The mean +/- SD weight of Maine Coon cats was significantly greater than that of domestic cats. Mean values of left ventricular internal dimension at end diastole and end systole (LVIDd and LVIDs, respectively), interventricular septal thickness at end systole (IVSs), left ventricular posterior wall thickness at end systole (LVPWs), left atrial dimension at end systole (LADs), and aortic root dimension (Ao) in Maine Coon cats differed significantly from values in healthy domestic cats. The greatest differences detected between the 2 groups involved values of LVIDd, LADs, and Ao. Linear regression analysis revealed a weak but significant correlation between weight and each of LVIDd, LVPWs, IVSs, Ao, LADs, and left ventricular posterior wall thickness at end diastole. CONCLUSIONS AND CLINICAL RELEVANCE: Values of several M-mode echocardiographic parameters in Maine Coon cats differ from those reported for domestic cats; these differences should be considered during interpretation of echocardiographic findings to distinguish between cardiac health and disease in this breed.     

Echocardiography in the chinchilla

Heart disease has been described in the chinchilla and, with increasing popularity as a pet, the demand for diagnostic evaluation and treatment has increased. The goal of this study was to determine reference values for echocardiographic measurements in chinchillas and the effect of anesthesia on these measurements. Seventeen clinically healthy adult chinchillas were studied. All animals were anesthetized with isoflurane by mask. Standard echocardiographic views were used. A difference was seen in the echocardiographic measurements for left ventricular systolic dimension, fractional shortening, aortic (Ao) diameter, left atrial (LA) diameter, ratio of LA diameter to Ao diameter, and peak flow velocities and ejection times for Ao and pulmonary artery flows between awake and anesthetized chinchillas.     

Reference values of two-dimensional and M-mode echocardiographic measurements as a function of body size in various equine breeds and in ponies

Introduction

The aim of this study was to establish echocardiographic reference values for the equine species using allometric regression equations based on body weight (BW) and thoracic circumference (TC).

Survival and echocardiographic data in dogs with congestive heart failure caused by mitral valve disease and treated by multiple drugs: a retrospective study of 21 cases

This retrospective study reports the survival time [onset of congestive heart failure (CHF) to death from any cause] of 21 dogs with mitral regurgitation (MR) and CHF treated with a combination of furosemide, angiotensin-converting enzyme inhibitor (ACEI, benazepril, or enalapril), pimobendan, spironolactone, and amlodipine. Baseline echocardiographic data: end-systolic and end-diastolic volume indices (ESVI and EDVI), left atrium to aorta ratio (LA/Ao), and regurgitant fraction (RF) are reported. Median survival time (MST) was 430 d. Initial dosage of furosemide (P = 0.0081) and LA/Ao (P = 0.042) were negatively associated with survival. Baseline echocardiographic indices (mean ± standard deviation) were 40.24 ± 16.76 for ESVI, 161.48 ± 44.49 mL/m(2) for EDVI, 2.11 ± 0.75 for LA/Ao, and 64.71 ± 16.85% for RF. Combining furosemide, ACEI, pimobendan, spironolactone, and amlodipine may result in long survival times in dogs with MR and CHF. Severity of MR at onset of CHF is at least moderate.     

Echocardiographic measurements of cardiac dimensions in normal Standardbred racehorses

ObjectivesThe aim of this study was to obtain echocardiographic measurements and establish reference ranges for 14 parameters in Standardbred racehorses in training.BackgroundSeveral studies have been published about cardiac measurements in Thoroughbreds, Standardbreds, National Hunt horses, Warmbloods and ponies; however, not all parameters have been published for the Standardbred trotter in training.Animals, materials and methodsThirty normal Standardbred racehorses in training were assessed by two-dimensional echocardiography (2-D) and M-mode echocardiography using standardized imaging planes. Mean values, standard deviations, 95% confidence interval for the means and 95% confidence interval for the cardiac parameters measured in the population were calculated. Furthermore, a general linear model was constructed using sex, age and body weight (bwt) of the horses as independent variables and the echocardiographic measurements as dependent variables. Multivariate linear regression analysis was performed with the level of significance at p < 0.05 for all the null hypotheses.ResultsReference ranges were established for 14 echocardiographic parameters in Standardbred racehorses. Weak linear relationships between echocardiographic measurements and body weight were observed for LVIDd, LVIDs, LVFWs, and AOD. Linear regressions on these parameters were used to calculate the 95% confidence intervals for the predicted values.ConclusionsThe data collected in this study provide reference values for the evaluation of Standardbred racehorses in training. Body weight has a negligible affect on most echocardiographic parameters in this homogeneous population, but did mildly influence the results of left ventricular and aortic measurements.