Hypercapnia and hyperlactatemia were positively associated with higher-grade arrhythmias during peak exercise in horses during poor performance evaluation on a high-speed treadmill.
Abstract: Cardiac arrhythmias are common in horses during exercise, especially immediately post-exercise. The objectives of this study were to: (1) describe the frequency and type of cardiac arrhythmias detected in horses during incremental high-speed treadmill exercise testing (ITET); (2) determine if arterial blood gas (ABG) changes at peak and immediately post-exercise were associated with arrhythmias; and (3) determine whether upper or lower airway disease was associated with exercising cardiac arrhythmias. Horses (n = 368) presenting for an ITET underwent resting and exercising upper airway endoscopy, resting, exercising and post-exercise electrocardiography, resting and post-exercise echocardiography and exercising ABG. Arrhythmias were graded by the most severe arrhythmia present. Grade 1 arrhythmias were defined as one or two atrial (APCs) or ventricular premature complexes (VPCs), or one APC and one VPC, detected in 6.9% at peak and 16% at 0-2 min post exercise.. Grade 2 arrhythmias were >2 APCs or VPCs, or both, detected in 5.8% at peak and 16.6% at 0-2 min post exercise. Grade 3 included complex arrhythmias (couplets, triplets, R on T, multiform complexes or paroxysmal atrial or ventricular tachycardia), detected in 4.4% at peak and 7.3% at 0-2 min post exercise. Both partial pressure of arterial CO (PaCO; P = 0.008) and lactate (P = 0.031) were significantly associated with arrhythmias occurring at peak exercise, but not immediately post-exercise. As PaCO and lactate increased, arrhythmia severity increased. Blood pH was significantly associated with grades 2 and 3 arrhythmias at 0-2 min post ITET (OR = 0.0002; P < 0.001). There was no significant association between grades 2 and 3 cardiac arrhythmias, inflammatory airway disease (IAD), or exercise-induced pulmonary hemorrhage (EIPH). When adjusted for lactate concentration (P = 0.06), higher PaCO concentrations in horses with and without exercising upper respiratory tract (URT) obstruction were associated with higher likelihood of grades 2 and 3 arrhythmias (P < 0.01). This study demonstrated that at peak exercise, with severe hypercapnia and hyperlactatemia, there was increased risk for grades 2 or 3 cardiac arrhythmias and, as the PaCO and lactate values increased further, the severity of those arrhythmias increased.
Copyright © 2020. Published by Elsevier Ltd.
Publication Date: 2020-11-09 PubMed ID: 33323171DOI: 10.1016/j.tvjl.2020.105572Google Scholar: Lookup
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- Journal Article
- Blood
- Cardiac Arrhythmias
- Cardiovascular Health
- Clinical Pathology
- Clinical Study
- Diagnosis
- Diagnostic Technique
- Disease Diagnosis
- Disease Etiology
- Equine Health
- Exercise
- Exercise Physiology
- Horses
- In Vivo
- Lactate
- Performance Horses
- Physiology
- Respiratory Health
- Treadmill Exercise
- Veterinary Medicine
- Veterinary Research
Summary
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This research study looks into the connection between higher levels of carbon dioxide (hypercapnia) and lactic acid (hyperlactatemia) in the blood and the incidence of severe arrhythmias in horses during high-speed treadmill exercise tests. The study also investigates whether these conditions or any airway disease might be linked to the occurrence of exercise-induced cardiac arrhythmias.
Objectives and Methodology of the Study
- The principal aim of this research was to examine the type and frequency of cardiac arrhythmias in horses during high-speed treadmill exercise testing (ITET). The secondary goals included assessing if arterial blood gas (ABG) changes were associated with the occurrence of arrhythmias and whether there was a correlation between airway diseases and cardiac arrhythmias during exercise.
- The study involved 368 horses, all of which underwent a series of tests such as resting and exercise-based upper airway endoscopy, electrocardiography, echocardiography, and ABG. Research scientists classified observed arrhythmias by their severity, with Grade 1 being the least severe and Grade 3 the most severe.
Results of the Study
- The results demonstrated that higher degrees of arrhythmias were significantly linked with higher partial pressure of arterial CO (PaCO) and lactate levels during, but not immediately after, peak exercise. It was observed that as the PaCO and lactate levels rose, the severity of arrhythmias also increased.
- Blood pH was found to be significantly linked with Grade 2 and 3 arrhythmias in the post-exercise period. No significant association was observed between heightened arrhythmias and inflammatory airway disease (IAD) or exercise-induced pulmonary hemorrhage (EIPH).
- When the researchers adjusted the data for lactate concentration, they found that higher PaCO levels in horses with or without exercise-based upper respiratory tract (URT) obstruction had a greater likelihood of experiencing Grade 2 and 3 arrhythmias.
Conclusion
- The study concluded that during peak exercise, the risk of Grade 2 or 3 cardiac arrhythmias increased with severe hypercapnia and hyperlactatemia. Additionally, as the values of PaCO and lactate rose further, the arrhythmias’ severity escalated as well. The research emphasizes the need for further investigations in order to definitively establish the cause-and-effect connection between these factors.
Cite This Article
APA
Reef VB, Davidson EJ, Slack J, Stefanovski D.
(2020).
Hypercapnia and hyperlactatemia were positively associated with higher-grade arrhythmias during peak exercise in horses during poor performance evaluation on a high-speed treadmill.
Vet J, 266, 105572.
https://doi.org/10.1016/j.tvjl.2020.105572 Publication
Researcher Affiliations
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania, 382 West Street Rd., Kennett Square, PA 19348, USA. Electronic address: vreef@vet.upenn.edu.
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania, 382 West Street Rd., Kennett Square, PA 19348, USA.
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania, 382 West Street Rd., Kennett Square, PA 19348, USA.
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania, 382 West Street Rd., Kennett Square, PA 19348, USA.
MeSH Terms
- Airway Obstruction / veterinary
- Animals
- Arrhythmias, Cardiac / physiopathology
- Arrhythmias, Cardiac / veterinary
- Blood Gas Analysis / veterinary
- Exercise Test / veterinary
- Female
- Horse Diseases / physiopathology
- Horses
- Hydrogen-Ion Concentration
- Hypercapnia / veterinary
- Hyperlactatemia / veterinary
- Male
- Physical Conditioning, Animal
Citations
This article has been cited 5 times.- Lo Feudo CM, Stucchi L, Conturba B, Stancari G, Zucca E, Ferrucci F. Medical causes of poor performance and their associations with fitness in Standardbred racehorses.. J Vet Intern Med 2023 Jul-Aug;37(4):1514-1527.
- Nath L, Stent A, Elliott A, La Gerche A, Franklin S. Risk Factors for Exercise-Associated Sudden Cardiac Death in Thoroughbred Racehorses.. Animals (Basel) 2022 May 18;12(10).
- Ter Woort F, Dubois G, Tansley G, Didier M, Verdegaal L, Franklin S, Van Erck-Westergren E. Validation of an equine fitness tracker: ECG quality and arrhythmia detection.. Equine Vet J 2022 Feb 9;55(2):336-43.
- Alberti E, Stucchi L, Lo Feudo CM, Stancari G, Conturba B, Ferrucci F, Zucca E. Evaluation of Cardiac Arrhythmias before, during, and after Treadmill Exercise Testing in Poorly Performing Standardbred Racehorses.. Animals (Basel) 2021 Aug 16;11(8).
- Nath LC, Elliott AD, Weir J, Curl P, Rosanowski SM, Franklin S. Incidence, recurrence, and outcome of postrace atrial fibrillation in Thoroughbred horses.. J Vet Intern Med 2021 Mar;35(2):1111-1120.
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