Honors Theses and Capstones

Date of Award

Spring 2019

Project Type

Senior Honors Thesis

College or School




Program or Major

Equine Studies: Equine Science

Degree Name

Bachelor of Science

First Advisor

John Keen

Second Advisor

Drew Conroy

Third Advisor

Pete Erickson


This research focused on 3D echocardiography of the aortic valve (AV) in horses. Aortic regurgitation (AR) can be a common finding in older horses, and in severe cases can result in decreased performance and even sudden cardiac death. Standard AR diagnosis includes 2D echocardiography from the right side of the horse. Three-dimensional echocardiography (3DE) records a pyramid of tissue, showing structures in the heart difficult to visualize in 2D methods, and can be more accurate as it does not rely as heavily on placement of the transducer. Nine images of normal AV’s were assessed, and still frames of anatomical structures were obtained. Area and circumference from the enface view, and diameter and cusp thicknesses from side and enface views were measured. These measurements were also taken on images from 5 horses with mild, 7 with moderate, and 2 with severe AR. 3DE images from the left side of 9 normal horses were taken for comparison. In normal valves, the edges of the cusps were visible but the centers were not from the right. The left coronary cusp was generally most visible from the right sided view. The cusp edges and lunulae of the aortic valve were thickened in horses with AR, with degree of thickening corresponding to AR severity. The center of the cusps appeared opaque in some horses with AR. There was a statistically significant positive correlation between thickness of the left coronary cusp and AR severity. Left sided images were generally of worse quality than those from the right, but in some cases there was better visualization of the right and noncoronary cusps. 3DE could potentially be used as a standard for diagnosis of AR, specifically by looking at cusp thicknesses, and could more specifically diagnose which part of the valve is affected by disease.