Atrial natriuretic peptide and cardiac troponin I concentrations in healthy Warmblood horses and in Warmblood horses with mitral regurgitation at rest and after exercise.

The study explores levels of atrial natriuretic peptide (ANP) and cardiac troponin I (cTnI) in Warmblood horses, both healthy and those with mitral regurgitation (MR), at rest and after exercise. It concludes that horses with MR show higher levels of ANP, and these levels relate to left heart dimensions and pressures, but not inevitably associated with exercise-induced stress or damage.

Objective and Methodology

• The principal goal of the study was to study the time series of plasma ANP (CpANP) and plasma cTnI (CpcTnI) in horses with Mitral Regurgitation (MR), as compared to healthy horses at rest and after workout. The association of CpANP with the measurements of the cardiac dimensions and intracardiac pressures was also examined.
• For this research, 15 healthy Warmblood horses and 7 Warmblood horses with MR were chosen. Cardiac dimensions at rest were noted using echocardiography while the horses underwent a standardized treadmill exercise. Biomarker concentrations and intracardiac pressures were measured before and after the exercise.

Results

• The results showed that Warmblood horses with MR had increased left atrial (LA) and left ventricular (LV) dimensions as compared to healthy horses.
• The pulmonary capillary wedge pressures (PCWP) and CpANP rose after exercise in all horses. However, horses with MR consistently exhibited higher PCWP and CpANP at rest as well as after exercising.
• Interestingly, the most significant difference in CpANP was noted 10 minutes post-exercise. CpANP was found to be directly proportional to PCWP and oddly and solely in healthy horses, to echocardiographic indices of LA and LV size and function.
• In terms of the other biomarker, CpcTnI, it maintained a low profile throughout the entire research period in both groups of horses.

Conclusions

• The research concluded that CpANP is elevated in horses suffering from MR and it correlates with the dimensions and pressures of the left heart. Despite the widespread assumption, MR does not necessarily lead to an intolerant attitude towards exercise or induce stress or damage to the myocardium during exercise.