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.     

Transthoracic echocardiography in Estrela Mountain dogs: reference values for the breed

Of 100 Estrela Mountain dogs, 74 were examined to obtain echocardiographic reference values for the breed. The influence of bodyweight, age and sex on different echocardiographic parameters was studied using either analysis of variance or regression analysis. Statistically significant differences were found between sex and heart rate as well as interventricular septal thickness at end-systole and left ventricular internal dimension at end-diastole. A statistically significant linear correlation was also found between several parameters and (1) age (mean arterial pressure, left ventricular internal dimension at end-systole, fractional shortening, circularity index in systole, aortic valve velocity time integral, pulmonic valve velocity time integral and mitral valve E wave peak velocity), (2) weight (left ventricular posterior wall thickness at end-diastole and end-systole, end-diastolic volume index, left atrium diameter, aortic valve peak velocity and mitral valve E wave deceleration time), (3) sex and age (left ventricle end-diastolic volume), and (4) sex and weight (aortic root diameter and pulmonic valve peak velocity). Reference values for the breed are presented, as well as dispersion graphics for selected parameters, based on a regression equation.     

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.     

Change in M-mode echocardiographic values in cats given ketamine

Determination was made of changes in heart rate and certain M-mode echocardiographic values in healthy cats given ketamine (3 to 5 mg/kg, IM). Heart rate and septal and left ventricular posterior wall thickness in diastole increased, and left ventricular internal diameter in diastole and shortening fraction decreased (P less than 0.02) after ketamine was given. With the adjustment for heart rate by analysis of covariance, left ventricular internal diameter in diastole, shortening fraction, and velocity of circumferential fiber shortening were significantly decreased (P less than 0.05) from base-line values.     

M-mode and Doppler echocardiographic reference values for male New Zealand white rabbits

OBJECTIVE: To determine M-mode and Doppler echocardiographic reference values in healthy New Zealand white rabbits. ANIMALS: 52 healthy male rabbits. PROCEDURES: The rabbits were anesthetized and M-mode measurements of the left ventricle, left atrium, and aorta and Doppler measurements of pulmonary and aortic outflow and mitral inflow were recorded. RESULTS: Mean +/- SD heart rate during echocardiographic examination was 155 +/- 29 beats/min. Mean +/- SD measurements in diastole and systole for the interventricular septum thickness, left ventricular internal diameter, and left ventricular free wall thickness were 2.03 +/- 0.37 mm and 3.05 +/- 0.45 mm; 14.37 +/- 1.49 mm and 10.25 +/- 1.22 mm; and 2.16 +/- 0.25 and 3.48 +/- 0.55 mm, respectively. Mean +/- SD left atrial-to-aortic diameter ratio was 1.17 +/- 0.14, and mean +/- SD mitral valve E-point-to-septal separation interval was 1.71 +/- 0.29 mm. Mean +/- SD for fractional shortening and ejection fraction were 30.13 +/- 2.98% and 61.29 +/- 4.66%, respectively. Mean +/- SD maximal aortic and pulmonary artery outflow velocities were 0.85 +/- 0.11 m/s and 0.59 +/- 0.10 m/s, respectively, and the peak E-to-peak A wave velocity ratio of the mitral valve was 2.19 +/- 0.46. CONCLUSIONS AND CLINICAL RELEVANCE: Results provide echocardiographic reference values for young adult male New Zealand white rabbits anesthetized with ketamine and medetomidine. Values obtained from unanesthetized rabbits, rabbits sedated with other agents, or rabbits of different size may differ from those reported here.     

Reference Values and Repeatability of B-Mode and M-Mode Echocardiographic Parameters in Healthy Donkey (Equus asinus)—The Guide to Assess Healthy Heart

Donkey (Equus asinus), the cheapest form of agricultural power in Egypt, is used principally as draught or pack animals and may also be ridden, or used for threshing, raising water, milling, and other work. The aim of the present study was to provide B-mode and M-mode echocardiographic reference ranges from a sample of population of donkeys (E. asinus) based on the probability theory and statistics. In the present study, B-mode and 2-dimensional guided M-mode echocardiography were performed on 44 clinically healthy donkeys (E. asinus) (22 males and 22 females), without any neither clinical nor echocardiographic evidence of cardiovascular diseases, aged 2–25 year old, and weighed 150–350 kg. The echocardiographic dimensions, including interventricular septum thickness at end diastole, interventricular septum thickness at end systole, left ventricular internal diameter at end diastole, left ventricular internal diameter at end systole, left ventricular posterior wall thickness at end diastole, and left ventricular posterior wall thickness at end systole were assessed. The cardiac function indices, including end diastolic volume, end systolic volume, stroke volume, ejection fraction, and fractional shortening were also measured. B-mode and guided M-mode echocardiographic examination of healthy donkeys revealed that both the interventricular septum thickness and the left ventricular posterior free wall were greater during systole than diastole. However, the left ventricular dimension during diastole was greater than systole. Furthermore, the recorded data of cardiac function indices, including end diastolic volume, end systolic volume, stroke volume, ejection fraction, and fractional shortening using B-mode echocardiography were closer to those recorded by guided M-mode echocardiography. To our knowledge, this is the first Egyptian study to report the echocardiographic reference ranges of donkeys (E. asinus) based on the probability theory and statistics, the coefficient of variation. The results of the present study can be used as standard and reference values for further echocardiographic studies in donkeys and represent a step in the identification, interpretation, and evaluation of cardiovascular disorders in such animals.     

Measurement of cardiac dimensions with two-dimensional echocardiography in the living horse.

Two-dimensional echocardiography (2DE) was performed on 22 unsedated Thoroughbred and part Thoroughbred horses weighing between 411 and 650 kg to establish normal reference values for 2DE measurements. Animals stood during examinations performed with a 3.5 MHz mechanical sector transducer using various transducer positions and tomographic planes. Right ventricular diameter (RVD), ventricular septal thickness (VSTh), aortic diameter (AoD), area of the chordal lumen of the left ventricle (CTA), left ventricular diameter (LVD) and left atrial diameter (LAD) were determined at ventricular end-diastole (Ed) and/or end-systole (Es). Fractional shortening (FS) of the left ventricle and end-systolic left atrial to aortic ratio (LAD-Es:AoD-Es) also were calculated. Echocardiographic data were related to body weight by linear regression analysis. Intra-observer variability was checked in five horses by measuring each parameter during each of 10 consecutive cardiac cycles. The 2DE data were compared with M-mode values in published reports. In the 18 horses whose weight did not exceed 551 kg, repeatable recordings of good quality were obtained, and 2DE measurements could be made using intra-cardiac reference points. Increasing body weight proved to impose substantial limitations on measurements taken with the available machine and transducer. This problem might be overcome by using probes of lower frequency or equipment with higher quality image display at greater depth. The following parameters correlated significantly to body weight: VSTh-Es (r = 0.69; P less than 0.01). AoD-Es (r = 0.64; P less than 0.01) and CTA-Es (r = 0.84; P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

ECHOCARDIOGRAPHIC REFERENCE VALUES IN WHIPPETS

The aim of the study was to establish reference echocardiographic values for whippets, to compare these values with previously published reference values for the general dog population, and to determine whether there is an influence of gender and breeding lines on echocardiographic measurements. Echocardiographic parameters from 105 apparently healthy whippets without cardiac symptoms were used to establish reference values for the breed and to compare these values with two previously reported reference ranges. The coefficients of the allometric equation Y= aM(b), useful to reconstruct normal M-mode and two-dimensional average values for whippets of varying weights, were calculated, as well as the lower and upper limits of the 95% prediction interval. First, we found that whippets have a significantly larger left ventricular diameter, increased left ventricular wall, and interventricular septum thickness than expected, in diastole as well as in systole. Fractional shortening was significantly lower than the reference value. Second, comparing males and females, taking body weight differences into account, females had a significantly larger left ventricular diameter in diastole and systole. Minor differences were found between racing and show pedigree dogs. In conclusion, the results of this study confirm that breed-specific reference values are needed in echocardiography. In whippets, the values found in this study can be used as references in order to avoid overinterpretation of cardiac dilation, hypertrophy, and/or decreased contractility in these dogs.     

Observer-dependent variability of quantitative clinical endpoints: the example of canine echocardiography

The objective of this study was to determine the intra- and inter-observer variability of echocardiographic measurements in dogs. Four observers with different levels of experience in echocardiography performed 192 echocardiographic examinations of six dogs on four different days. The lowest within- and between-day coefficients of variation (CV) (%) were 13.8 and 5.2 for the right ventricle in diastole, 8.9 and 4.5 for the interventricular septal thickness in diastole (6.3 and 7.0 in systole), 7.7 and 9.4 for the left ventricular free-wall thickness in diastole (8.1 and 5.2 in systole), 3.1 and 5.0 for the left ventricular end-diastolic diameter (6.2 and 7.0 for end-systolic diameter), 10.2 and 10.8 for the left ventricular shortening fraction, and 8.2 and 9.8 for the left atrium/aorta ratio, respectively. Most of these lowest CVs were observed by the two most experienced observers. Conversely, all maximum values were obtained with the two less experienced observers. These differences in observer-dependent variability may considerably influence the minimum number of animals required to detect a treatment-associated change in echocardiographic variables.     

Normal values of the canine M-mode echocardiogram

M-mode echocardiograms were recorded from 40 healthy dogs, awake and unsedated, in left lateral recumbent position. Fifteen echocardiographic measurements were taken and correlated with body weights using linear regression equations. The left ventricular internal dimension in systole and diastole, the left ventricular wall thickness, the aortic root dimension, and the left atrial dimension had high correlation coefficients (r2), ranging from 0.756 to 0.619. The fractional shortening of the left ventricle in systole (39% +/- 6%) and the left atrial to aortic root ratio (0.99 +/- 0.10) were not linearly related to body weights and had constant values.