Stress echocardiography in warmblood horses: comparison of dobutamine/atropine with treadmill exercise as cardiac stressors.

The research article focuses on a study comparing the effects of treadmill exercise and a combination drug (dobutamine and atropine) as cardiac stressors for warmblood horses. The results show that while both methods successfully elevate the heart rate, the drug combination provides a longer time window for detailed cardiac examinations.

Objective of the Study

The main objective of this study was to ascertain whether a combination of dobutamine and atropine could create a level of cardiac stress comparable to that achieved through treadmill exercise in warmblood horses. The researchers aspired to determine which method offered better conditions for performing detailed circuit-system evaluations.

Methodology

• Both electrocardiography and echocardiography were carried out on ten warmblood horses before, during, and after cardiac stress tests.
• The stress tests included a standardized treadmill exercise and a dual-drug treatment involving administration of dobutamine and atropine.
• The researchers kept track of heart rates throughout, and noted down maximum rates, as well as the rate of decrease post stress test.

Findings

• The maximum heart rate was achieved during the treadmill exercise, reaching up to 175 beats per minute (bpm).
• The treadmill exercise led to a quick reduction in heart rate post exercise, limiting the period of high heart rate necessary for conducting echocardiography.
• The combined usage of dobutamine and atropine also led to a significant surge in heart rate, and the heart rate slowly diminished after the administration of this combination treatment – prolonging the period with high heart rates suitable for examination.
• Echocardiographic exams revealed decreases in left ventricular (LV) dimensions, an increase in LV wall thickness, and a reduction in stroke volume post-exercise and during pharmacologic stress testing as compared to baseline.
• The alterations in echocardiographic variables appeared more pronounced during the dobutamine and atropine treatment period.

Conclusion

The article concludes that the combination of dobutamine and atropine is a useful means to induce a heart rate increase in horses, similar to that obtained through exercise. However, it has the advantage of prolonging the period suitable for performing detailed cardiac examinations, and not requiring an increase in dobutamine dosage.