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

Influence of age, sex, bodyweight, and training on echocardiographic measurements in healthy mixed-breed donkeys

The donkey has always been a notable working animal and its importance as a companion animal has been growing over the last few years. However, there are only a few studies about cardiology in this species. Therefore, this study aimed to evaluate the influence of age, sex, training, and bodyweight on cardiac dimension in mixed-breed donkeys. Forty-five clinically and para-clinically healthy mixed-breed donkeys were included, and B-mode and M-mode echocardiographic measurements were recorded. Multivariate linear regression analysis was performed to identify the effect of age, sex, bodyweight, and training on cardiac measurements. Most of the echocardiographic measurements showed a strong statistically significant correlation with bodyweight. Linear regression analysis between echocardiographic measurements and bodyweight was performed to obtain the values of the intercept and slope of the linear equation to calculate the echocardiographic measurements as a function of bodyweight. This is the first study reporting a strong linear correlation between echocardiographic measurements and bodyweight and reporting a correlation between training and echocardiographic parameters in donkeys, suggesting that this variable should be considered when assessing cardiac dimensions in these animals.

Effects of conditioning on the left ventricular function of young purebred Arabian horses

The effects of conditioning on cardiac function in young horses is still unknown. For this reason, this study evaluated the left ventricular (LV) function of young horses by echocardiography after six weeks of conditioning. Fourteen untrained young purebred Arabian horses were evaluated at rest and after a stress test (ST) before and after a six-week conditioning program. There was an increase in V4 (p < 0.001) after conditioning, as well as a reduction in both heart rate (HR) at rest and peak HR during the ST (p < 0.001). There was also a reduction in internal diameter, along with an increase in interventricular septal, free wall and mean thicknesses and LV mass (p < 0.05). After the ST, the conditioned animals showed higher values of velocity time integral, stroke volume, systolic and cardiac indices, ejection (ET) and deceleration times (DT), end-diastolic volume, time to onset of radial myocardial velocity during early diastole and time to peak of transmitral flow velocity, in addition to reduced pre-ejection period (PEP), PEP/ET ratio and mean velocity of circumferential fiber shortening (p < 0.05). The conditioning protocol promoted physiological adaptations that indicate an improvement in the animals' aerobic capacity associated with an enhanced left ventricular function.

Influence of Dorper lamb development from birth to 120 days of age on clinical and echocardiographic parameters

The expansion of the sheep model in research represents an attractive and economically beneficial academic reason for investigations in sheep echocardiography. The present study aimed to evaluate the clinical and echocardiographic parameters in Dorper lambs during the developmental period. Emphasis was placed on the use of the species in translational research for the echocardiographic diagnosis of congenital heart diseases, which can contribute to improvements in interventionist techniques. Ten Dorper lambs were evaluated at the following time points: 24 h after birth and 7, 14, 21, 30, 60, 90 and 120 days of age. Clinical parameters were compiled, and echocardiogram records were obtained without sedation. Rectal temperature was lower on the first day compared to the others. From 21 days of life, there was a reduction in HR, with differences between time points. Mean and systolic blood pressure differed, with the highest values at 90 and 120 days of age. The thickness of the interventricular septum in diastole (IVSd) increased as age progressed, with the highest value at 120 days of age, and the same occurred for LVIDd (left ventricle internal diameter in diastole), LVFWd (left ventricular free wall thickness in diastole), IVSs (interventricular septum thickness in systole), LVIDs (left ventricle internal diameter in systole) and LVFWs (left ventricular free wall thickness in systole). There were differences in the size of the LA, Ao and LA/Ao ratio, which were greater at 90 days and 120 days of age. Echocardiographic changes accompany the development of lambs, where changes in echocardiographic parameters are evident with advancing age. The echocardiographic measurements in lambs obtained in the present study are similar to those in newborns.

Reference Values of M-mode Echocardiographic Parameter in Adult Toy Breed Dogs

Introduction:

Myxomatous mitral valve disease (MMVD) is one of the most common heart diseases in dogs, and there is a dearth of reports that have investigated reference values for left ventricular end-diastolic internal diameter corrected for body weight (LVIDDN) exclusively in toy breeds.

Animals

Eighty-six client-owned healthy dogs weighing <5 kg, including Toy Poodles, Chihuahuas, Yorkshire Terriers, Papillon, and other small breeds or small mixed breeds (mixed breed, Pomeranian, dachshund, Shih Tzu, and Maltese). In this retrospective single-center study, data were collected from dogs attending clinic for annual checkup between April 2014 and March 2021.

Materials and Methods

Experienced echocardiographers performed transthoracic echocardiography, with reference ranges established using healthy dogs. Measurements of body weight (BW), heart rate, and several echocardiographic variables were obtained. The association between BW and echocardiographic parameters was assessed by linear regression analyses. M-mode measurements were obtained and normalized using equations developed from the regression analyses.

Results

The LVIDDN value for 95% of dogs weighing <5 kg was achieved by dividing the M-mode measurement by BW raised to the power 0.332. The upper limit of the prediction interval for breeds weighing <5 kg was much lower than the value currently applied.

Conclusions

We propose a reference LVIDDN value of ≥1.6 for the diagnosis of stage B2 MMVD in toy breed dogs. The results of our study will guide clinicians in deciding when to start treatment for MMVD in small breed dogs.

Partial atrioventricular septal defect in an adult sport horse

A partial atrioventricular septal defect, represented as a large ostium primum atrial septal defect and common (bridging) atrioventricular valve leaflets with cleft septal leaflet of the mitral valve, was diagnosed incidentally in a nine-year-old warmblood gelding used for show jumping. Initial examination findings and a three-year follow-up are documented in this report. The horse was first presented for the evaluation of chronic coughing. A left-sided, grade 4/6 holosystolic (band-shaped) murmur was identified along with a similar right-sided, grade 3/6 heart murmur. Echocardiography revealed a 6.4 cm diameter communication in the ventral atrial septum, considered an ostium primum atrial septal defect, with bidirectional shunting. A hypertrophic septomarginal trabecula, a thickened tricuspid valve, a cleft septal leaflet of the mitral valve, moderate mitral and tricuspid regurgitation likely related to leaflet prolapse, mild aortic regurgitation, and signs of moderate right ventricular volume overload were found as well. Electrocardiography showed no arrhythmias neither at rest nor during treadmill exercise. The owner continued to use the horse for show jumping. No exercise intolerance or other signs of disease were noted. Follow-up examination was performed three years after initial presentation. Contrast echocardiography confirmed the presence of right-to-left shunting through the atrial septal defect. Compared with the initial examination, the left ventricular internal diameter on M-mode echocardiography had increased. Occasional ventricular premature depolarizations were noted on the resting and exercise electrocardiogram. This is the first description of a clinically asymptomatic partial atrioventricular septal defect in an adult sport horse.

Two-dimensional, M-mode and left atrial velocity echocardiographic measurements in healthy Norwegian-Swedish Coldblooded Trotters

INTRODUCTION

The Norwegian-Swedish Coldblooded Trotter (NSCT) is an important breed in Norwegian and Swedish harness racing. In spite of this, little is known about its cardiac measurements and factors that may influence these. The aims of this study were to establish reference intervals (RI) for a series of conventional echocardiographic variables, primarily of the left heart, in NSCTs in race training and to evaluate any effects age, gender, estimated body weight (EBW), number of starts and racing performance may have on these.

ANIMALS

Sixty-three apparently healthy NSCTs in race training.

METHODS

Observational study, convenience sampling. All horses were examined unsedated in their normal stabling environment. Auscultatory and echocardiographic examinations were performed. Means, standard deviations, medians and confidence intervals of the RI limits were used to summarize the data. The relationship between selected echocardiographic variables and age, gender, EBW, racing performance and number of starts were explored using linear regression analyses.

RESULTS

Reference intervals were determined for routinely used echocardiographic variables. Data for left atrial velocity were also obtained. Increasing age, number of starts and money earned significantly increased all cardiac measurements. Males had significantly higher ventricular measurements than females. Great vessel measurements increased with increasing EBW. Horses with faster recorded racing times had generally significantly increased cardiac measurements. Clinically insignificant valvular regurgitation was a common finding, particularly at the tricuspid and pulmonary valves.

CONCLUSIONS

The RIs described and the factors that may affect these will assist clinicians in interpreting echocardiograms of NSCTs with suspected cardiac disease or poor performance.

Two-dimensional echocardiographic measurements of the right coronary artery in healthy horses - a pilot study

Background

Precise understanding of the dimensions of the vascular lumina is essential for accurate interpretation of cardiac vessels imaging. To the authors’ best knowledge, this is the first study focusing on the ultrasound measurement of the right coronary artery (RCA) in the horse. The aim of this study was to determine both the ultrasonographic range of the normal diameter and lumen area of the RCA in horses and the influence of gender, age and level of training on the RCA dimensions. An additional aim of the study was to assess intra- and inter-observer repeatability of the collected measurements.

Methods

Thirty-six privately owned, healthy horses were included in the study. The internal lumen diameter and the area of the RCA were measured in the right parasternal long axis view in the 3rd intercostal space during systole and diastole. The results were compared between groups using the analysis of variance (ANOVA) and Student’s t-test. The correlation between the physiological parameters and the RCA was assessed using Pearson correlation coefficient. Student’s t-test was used to compare the results obtained by two researchers and from two scanners.

Results

The mean diameter of the RCA was 13.1 ± 1.5 mm in systole and 11.5 ± 1.3 mm in diastole, and the mean area was 1.3 ± 0.2 cm² and 1.1 ± 0.2 cm², respectively. There were no statistically significant measurement differences between geldings and mares. A positive correlation between body weight and RCA dimensions as well as height and RCA dimensions were seen. There was a negative correlation between the age and the RCA area. A statistically significant difference in the RCA area was seen between race and retired horses. Intra- and inter-observer agreement was strong with a few statistically significant differences.

Conclusions

The age, size, and level of training may affect the ultrasound measurement of the RCA in horses. Non-invasive transthoracic echocardiography may be used to assess the size of the right coronary vessel in various types of horses.