Right ventricular function during pharmacological and exercise stress testing in horses.

This research investigates how strenuous exercise affects the function of the right ventricle in horses. The study uses post-exercise and drug-induced stress tests to explore this, concluding that exercise significantly impacts right ventricle function and that drug-induced stress tests fail to accurately replicate the effects of exercise.

Overview of the Study

• The research aimed to comprehend how right ventricle function in horses is influenced by rigorous exercise.
• To achieve this, researchers conducted post-exercise evaluations and pharmacological (drug-induced) stress echocardiograms on ten healthy horses in a randomized cross-over design.
• A treadmill was used for the exercise tests while an infusion of atropine-dobutamine, a type of medication, was employed for pharmacological testing.

Findings of the Research

• Researchers observed increased heart rate, systemic blood pressure, and cardiac output during echocardiography after exercise when compared to the maximum pharmacological stress.
• Systolic pulmonary artery pressure was significantly higher after the exercise test and during immediate post-exercise echocardiography than under the effects of maximum pharmacological stress.
• Right ventricular diameters and the ratio of systolic right to left ventricular area were higher after exercise.
• Right ventricular fractional area change significantly decreased post-exercise but showed an increase during pharmacological stress echocardiography.

Troponin I Concentration

• Researchers observed that the concentration of cardiac troponin I, a protein marker of heart damage, was significantly higher 2 hours after the pharmacological test compared to baseline values and post-exercise values.
• The highest value was found post-exercise in the horse that had the highest systolic pulmonary artery pressure and the lowest right ventricular fractional area change.

Conclusion from the Study

• The researchers concluded that pharmacological stress testing should not be used in future studies on right ventricular adaptations in athletic horses.
• This is because such testing does not reproduce the physiological effects and stress that exercise induces on the horse’s heart, particularly on the right ventricle.