Prospective pre- and post-race evaluation of biochemical, electrophysiologic, and echocardiographic indices in 30 racing thoroughbred horses that received furosemide

Abstract

BackgroundExercise induced cardiac fatigue (EICF) and cardiac dysrhythmias are well described conditions identified in high-level human athletes that increase in frequency with intensity and duration of exercise. Identification of these conditions requires an understanding of normal pre- and post-race cardiac assessment values. The objectives of this study were to (1) characterize selected indices of cardiac function, electrophysiologic parameters, and biochemical markers of heart dysfunction prior to and immediately after high level racing in Thoroughbred horses receiving furosemide; and (2) create pre- and post-race reference values in order to make recommendations on possible screening practices for this population in the future.ResultsThirty Thoroughbred horses were enrolled in the study with an age range of 3–6 years. All horses received furosemide prior to racing. Physical exams, ECGs, and echocardiograms were performed prior to racing (T0) and within 30–60 min following the race (T1). Blood samples were obtained at T0, T1, 4 h post-race (T4) and 24 h after the race (T24). Electrolytes, hematocrit, cardiac troponin I, and partial pressure CO2 values were obtained at all time points. Heart rate was significantly increased post-race compared to baseline value with a median difference of 49 bpm, 95% CI [31,58],(P < 0.0001). No dysrhythmias were noted during ECG assessment. Following the race, an increase in number of horses demonstrating regurgitation through the aorta and AV valves was noted. Systolic function measured by fractional shortening increased significantly with a mean difference of 7.9%, 95% CI [4.8, 10.9], (P < 0.0001). Cardiac troponin I was not different at pre- and immediately post-race time points, but was significantly increased at T4 (P < 0.001). Troponin returned to baseline value by T24.ConclusionsThis study utilized a before and after study design where each horse served as its own control, as such the possible effect of regression to the mean cannot be ruled out. The reference intervals generated in this study may be used to identify selected echocardiographic and electrocardiographic abnormalities in racing horses receiving furosemide.

Evaluation of a smartphone‐based electrocardiogram device accuracy in field and in hospital conditions in horses

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Comparison of Standard Electrocardiography and Smartphone-Based Electrocardiography Recorded at Two Different Anatomic Locations in Healthy Meat and Dairy Breed Does

“…The pairing of smartphone technology with a wireless enabled ECG recorder has resulted in the ability to record ECG tracings with less cumbersome equipment than has traditionally been utilized for veterinary species. These devices have demonstrated efficacy for cats ( 3 ), dogs ( 4 ), horses ( 5 , 6 ), dairy cattle ( 7 ), and water buffalo calves ( 8 ), but currently no studies describe the use of this new technology for goats.…”

Effects of two‐dose intravenous administration of furosemide on clinical variables, electrocardiographic indices and serum electrolytes in dromedary calves

“…Gunter‐Harrington et al. (2018) showed changes in cardiac parameters including HR and ECG indices without affecting cardiac biomarkers and ECG indices following furosemide administration in Thoroughbred horses. It can be stated that the changes in ECG indices following furosemide administration were due to changes in electrical conduction of the myocardial action potential following electrolyte imbalances (Gunter‐Harrington et al., 2018).…”