Echocardiographic and clinical effects of two sedative doses of Dexmedetomidine in healthy horses.

This study involves an examination of the effects of two sedative doses of dexmedetomidine (DEX) on the heart activity of horses, using echocardiography.

Objective of the Study

• This study aimed to investigate how sedation from dexmedetomidine (DEX), an alpha-2 agonist, influenced echocardiographic measurements in horses, a subject that had not previously been explored in this species.

Research Methodology

• In total, six healthy female crossbred horses, each weighing between 250-330 kg, were included in the study.
• The horses underwent echocardiography before and after sedation with DEX administered intravenously at a low dose of 3.5 μg/kg (LD) and a high dose of 7 μg/kg (HD).

Results of the Study

• Findings revealed a significant increase in the diameters of the pulmonary artery and the left atrium at the end of the heart’s contraction phase (end-systole) after administering the HD of DEX. This also applied to the aortic valve diameter at end-systole after both the LD and HD treatments.
• Similarly, the internal diameter of the left and right ventricles at end-systole showed significant enlargement after both the LD and HD treatments.
• Contrastingly, the average and peak values of pulmonary velocity and the gradient of pulmonary pressure decreased significantly after both LD and HD treatments.
• Despite these modifications, the remaining cardiac dimensions, various indicators of cardiac functionality, and the existence and severity of any leakage in heart valves (valvular regurgitation) were unaffected by sedation.

Conclusion of the Study

• This study demonstrated that different doses of the sedative DEX have a comparable effect on most echocardiographic parameters of horses. Like other alpha-2 agonists, DEX does influence certain echocardiographic parameters.