Demonstration of regional differences in equine ventricular myocardial velocity in normal 2-year-old Thoroughbreds with Doppler tissue imaging.

The study explores the use of Doppler tissue imaging (DTI) as a non-invasive method to measure myocardial velocity and assess regional cardiac function in horses. The research found regional differences in myocardial velocities in different parts of the equine ventricle, and concluded that DTI, particularly spectral (SDTI), can be a valuable tool for studying these discrepancies and potentially detecting myocardial dysfunction.

Study Objective

• The researchers aimed to examine the performance of Doppler tissue imaging in assessing myocardial velocity, particularly regional differences, in the equine ventricle.
• The study was further focused on developing a reproducible DTI examination method for horses and documenting differences in myocardial velocity in various regions of a normal equine ventricle.

Methods

• The study involved 20 clinically normal 2-year-old Thoroughbreds and a 6-year-old Thoroughbred, which was examined six times to determine the repeatability of the method.
• Both spectral (SDTI) and color Doppler tissue imaging (CDTI) were used for the study, examining five ventricular regions: the right ventricular wall, interventricular septum, and left, right, and caudal parts of the left ventricle.

Findings

• The examination showed three main movements in the ventricular walls: in systole, early diastole, and late diastole. The most rapid movement was observed in the left region of the left ventricle and the interventricular septum.
• While CDTI’s individual repeatability was poor, SDTI produced repeatable maximum myocardial velocity estimates during systole and early diastole.
• Regional differences in both peak mean and maximum myocardial velocities were noticeable in systole and early diastole, but not in late diastole.

Conclusions

• The study confirmed that the SDTI modality of DTI produces the most repeatable data, with potential to be a valuable non-invasive tool for studying early diastolic function of equine ventricles.
• The study also affirmed DTI’s potential as a clinical and research tool, specifically for studying regional myocardial movement and detecting suspected cases of myocardial dysfunction.