Cardiac morphology changes in horses as a response to various types of sports

Cardiovascular problems can cause poor performance and sudden cardiac death during high-intensity competitions in athletics both humans and horses. A cardiac examination is one of the most important parameters used to define cardiac performance and cardiovascular diseases in sports horses. Some studies look at the cardiac morphology of horses from racing, eventing, endurance, and dressage. However, there is no information directly comparing these sports on the cardiac response. The objective was to evaluate the cardiac response of horses to various types of sports. Forty-eight horses were enrolled in this study and divided into 4 groups according to the type of sport: 12 control nonathlete horses, 12 show-jumping horses, 12 dressage horses, and 12 endurance horses. Electrocardiography with modified precordial leads was used to obtain electrophysiological heart function, and transthoracic echocardiography was evaluated. There were no significant differences among the groups concerning mean age and body weight. The electrocardiography and echocardiography results suggested that left ventricular internal diameter was highly associated with long-duration high-intensity exercise, such as endurance sports, and left ventricular wall thickness was significantly associated with short-duration high-intensity sports, such as show jumping. This study demonstrated exercise-induced cardiac morphology changes in each type of sports training.