Use of the cardiopulmonary flow index to evaluate cardiac function in thoroughbred horses.

The research assesses the usage of the cardiopulmonary flow index (CPFI) to evaluate cardiac function in horses specifically those diagnosed with heart disease. The CPFI is found to be a more sensitive measure of cardiac function than cardiac output in horses.

Research Methodology and Subjects

• The study observed a group of 10 horses diagnosed with cardiac disease, all showing signs of chronic toxic myocarditis. The conditions of these horses were likely due to exposure to feed contaminated with salinomycin, an ionophore.
• The cardiac function of these horses was compared to that of a control group of healthy horses. The comparison involved measuring both the Cardiopulmonary Flow Index (CPFI) and cardiac output of both groups of horses.
• The CPFI, a calculation of the ratio of cardiopulmonary blood volume to stroke volume, was determined through simultaneous recording of a radiocardiogram and an electrocardiogram.

Main Findings and Comparisons

• Significant differences were found in the average CPFI measurements between the control group and the horses diagnosed with heart disease. These differences were particularly prominent in cases with macroscopically visible myocardial fibrosis, discovered during a post-mortem examination.
• However, no significant differences were observed in the measures of cardiac output between the two groups.

Effects of Pharmacological Acceleration

• The research further investigated the impact of pharmacological acceleration of heart rate on the CPFI. The mean CPFI and the slopes of the regression lines of CPFI on heart rate differed significantly among the horses in the control group and the primary group.
• The differences were notably pronounced at heart rates close to the resting heart rates of the individual horses.

Research Conclusion

• Based on the results gathered, the CPFI was identified as a more sensitive measure of cardiac function in horses when compared to cardiac output.
• This implies that the CPFI could be a more effective means of assessing cardiac function in horses, particularly those diagnosed with heart disease or at risk of the same.