A review of the current diagnostic methods of aortic regurgitation in the horse

Aortic regurgitation (AR) is an important condition in equine medicine. It is considered a clinically relevant cardiac disease in horses, and the prevalence of the disease changes according to the study population, type of sport, and breed. Aortic regurgitation can be acute or chronic, and the diastolic reversal of blood from the aorta into the left ventricle can be longstanding enough to develop congestive heart failure, exercise intolerance, poor athletic performance, dyspnea, ventricular arrhythmias, and sudden cardiac death. The diagnostic methods used in clinical practice are noninvasive pulse pressure measurement, two-dimensional and M-mode echocardiography, and most prominently, color flow, pulse wave, and continuous-wave Doppler echocardiography. Recently, tissue Doppler imaging and two-dimensional speckle tracking have been reported as diagnostic methods for horses with aortic regurgitation. The influence of this disease on athletic performance needs further investigation, mainly because it can have an economic impact on owners of athlete horses, and accurate diagnosis and classification are the cornerstones to understanding the effects of the disease. The diagnosis of aortic regurgitation must be made using a multi-parameter approach, especially if an association between aortic regurgitation and poor athletic performance is suspected. Therefore, this review aimed to integrate and create a compilation of current diagnostic methods for diagnosing and classifying aortic regurgitation in horses.