Quantitative two-dimensional echocardiography in the horse: a review.

This article reviews studies using two-dimensional echocardiography (2DE) to measure heart parameters in horses, explores how variations in breed, body weight, and measurement methods affect these figures, and discusses 2DE usage in diagnosing equine cardiac diseases.

Introduction to Two-Dimensional Echocardiography in Equine Cardiology

• The article reviews the use of quantitative two-dimensional echocardiography (2DE), a method used to monitor and measure specific parameters of the equine heart, a practice that’s been in use since the early 1990s.
• When first used, parameters such as linear and area dimensions, as well as left ventricular volume, were validated by comparing measurements obtained during in vitro 2DE and those derived from autopsy measurements.
• These initial studies helped establish specific planes and intracardiac reference points for in vivo (within a living organism) measurements.

Established 2DE Values for Healthy Horses

• Few authors have determined and published 2DE measurements for healthy adult horses.
• The data obtained from these studies, although diverse, were consistently comparable with measurements from M-mode echocardiography- a standard method employed in measuring heart structures.
• The article highlights that differences in the measured parameters often emanate from the variations in the breed, body weight of the study populations, and also from the technical disparities between M-mode and 2DE measurement methods.

Utility of 2DE in Equine Cardiac Diseases

• There’s limited information on the potential application of 2DE values in diagnosing equine cardiac diseases.
• However, in one study, horses exhibiting aortic insufficiency showed significant increases in various parameters including; left ventricular chamber size, aortic root diameter, shortening fraction, and left ventricular thickness. It’s noteworthy that these values were primarily measured using M-mode echocardiography, but the diastolic left ventricular enlargement was additionally measured and demonstrated through 2DE.
• In a separate study involving horses with mitral insufficiency, there were elevated diastolic measurements of left ventricular and atrial cross-sectional internal diameters, captured through the use of 2DE.

In conclusion, the use of two-dimensional echocardiography presents an added variety in measuring illustrative parameters of the equine heart, both in health and disease. However, more research is needed to fully understand its potential in diagnosing and monitoring equine cardiac conditions.