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Avison A, Gelzer AR, Reef VB, Wulster Bills KB, de Solis CN, Kraus MS, Slack J, Stefanovski D, Deacon LJ, Underwood C. Twenty-four hour continuous transvenous temporary right ventricular pacing in healthy horses. J Vet Intern Med 2024; 38:1751-1764. [PMID: 38514200 PMCID: PMC11099695 DOI: 10.1111/jvim.17027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 02/13/2024] [Indexed: 03/23/2024] Open
Abstract
BACKGROUND The ability to perform transvenous temporary cardiac pacing (TV-TP) is critical to stabilize horses with symptomatic bradyarrhythmias. Reports of successful TV-TP in horses are limited, and only briefly describe short-term pacing. OBJECTIVE To describe temporary, medium-term (24 h) transvenous right ventricular pacing in awake horses using a bipolar torque-directed pacing catheter. ANIMALS Six healthy adult institutional teaching horses. METHODS Prospective experimental study with 2 immediately successive TV-TP lead placements in each horse with a target location of the RV apex. One placement was performed primarily with echocardiographic guidance and 1 primarily with fluoroscopic guidance. In all placements, corresponding images were obtained with both imaging modalities. Horses were then paced for 24 h, unrestricted in a stall with continuous telemetric ECG monitoring. Echocardiographically determined lead position, episodes of pacing failure in the preceding 6 h, and pacing thresholds were recorded every 6 h. Pacing failure was defined as a period of loss of capture longer than 20 s. RESULTS Pacing leads were placed with both guidance methods and maintained for 24 h with no complications. Two horses with leads angled caudally in the right ventricular apex had no pacing failure, the remaining 4 horses had varying degrees of loss of capture. Leads located in the right ventricular apex had longer time to pacing failure and lower capture thresholds P < 0.05. CONCLUSIONS AND CLINICAL IMPORTANCE Medium-term TV-TP is feasible and has potential for stabilization of horses with symptomatic bradyarrhythmias. Lead position in the right ventricular apex appears optimal. Continuous ECG monitoring is recommended to detect pacing failure.
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Affiliation(s)
- Amanda Avison
- Department of Clinical Studies, New Bolton CenterSchool of Veterinary Medicine, University of PennsylvaniaKennett SquarePennsylvaniaUSA
| | - Anna R. Gelzer
- Department of Clinical Sciences and Advanced MedicineSchool of Veterinary Medicine, University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Virginia B. Reef
- Department of Clinical Studies, New Bolton CenterSchool of Veterinary Medicine, University of PennsylvaniaKennett SquarePennsylvaniaUSA
| | - Kathryn B. Wulster Bills
- Department of Clinical Studies, New Bolton CenterSchool of Veterinary Medicine, University of PennsylvaniaKennett SquarePennsylvaniaUSA
| | - Cris Navas de Solis
- Department of Clinical Studies, New Bolton CenterSchool of Veterinary Medicine, University of PennsylvaniaKennett SquarePennsylvaniaUSA
| | - Marc S. Kraus
- Department of Clinical Sciences and Advanced MedicineSchool of Veterinary Medicine, University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - JoAnn Slack
- Department of Clinical Studies, New Bolton CenterSchool of Veterinary Medicine, University of PennsylvaniaKennett SquarePennsylvaniaUSA
| | - Darko Stefanovski
- Department of Clinical Studies, New Bolton CenterSchool of Veterinary Medicine, University of PennsylvaniaKennett SquarePennsylvaniaUSA
| | - Lindsay J. Deacon
- Department of Clinical Studies, New Bolton CenterSchool of Veterinary Medicine, University of PennsylvaniaKennett SquarePennsylvaniaUSA
| | - Claire Underwood
- Department of Clinical Studies, New Bolton CenterSchool of Veterinary Medicine, University of PennsylvaniaKennett SquarePennsylvaniaUSA
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Durando MM, Slack J, Birks E, Belcher C, Kohn C. Premature depolarisations in horses competing in United States Eventing Association and Fédération Equestre Internationale-sanctioned 3-day events. Equine Vet J 2024; 56:59-68. [PMID: 37248851 DOI: 10.1111/evj.13948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 05/04/2023] [Indexed: 05/31/2023]
Abstract
BACKGROUND Injuries and sudden death during the cross-country (XC) phase of eventing have raised interest in the frequency and types of cardiac arrhythmias occurring in these equine athletes. OBJECTIVES To characterise the frequency and types of rhythm disturbances and examine possible risk factors for premature depolarisations (PDs) occurring during the XC phase of United States Eventing Association (USEA) and Fédération Equestre Internationale (FEI)-sanctioned events. STUDY DESIGN Prospective, cross-sectional study. METHODS Continuous electrocardiographic (ECG) recordings were obtained from horses prior to, during and immediately following the XC competition. Physiological rhythms pre-XC were included in the arrhythmia group for analysis. The frequency of PDs was calculated for all horses, as well as by division. PDs were categorised by complexity (singles, couplets, triplets, complex) and variably grouped for statistical analysis. Multiple logistic regression was used to identify risk factors for the presence of specific cardiac arrhythmia groupings during XC. RESULTS PDs were identified in 42/75 horses (56% [45, 67]) during XC. Horses competing in the upper divisions of eventing had higher odds for having any PD during XC compared to the lower divisions (OR = 17.5 [4.3, 72.01], p = 0.006). The amount of time the heart rate (HR) was greater than 199 beats per minute (BPM) was associated with more complex arrhythmias (triplets, salvos and tachyarrhythmias) (OR = 1.01 [1.0, 1.02], p = 0.005). An arrhythmia at rest (physiological or PD) was associated with arrhythmia in the early recovery period (OR = 3.5 [1.1, 10.8], p = 0.03). MAIN LIMITATIONS Convenience sampling and technical challenges of continuous ECG recordings under competition settings limited the number of enrollments. CONCLUSIONS PDs were seen in a high percentage of horses during the XC competition. Upper levels and time the HR was greater than 199 BPM were related to PD presence and complexity.
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Affiliation(s)
- Mary M Durando
- Equine Sports Medicine Consultants, Newark, Delaware, USA
| | - Joann Slack
- New Bolton Center, University of Pennsylvania, Kennett Square, Pennsylvania, USA
| | - Eric Birks
- Equine Sports Medicine Consultants, Newark, Delaware, USA
| | - Carolyn Belcher
- Georgia Department of Natural Resources, Coastal Resources Division, Brunswick, Georgia, USA
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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; 37:1514-1527. [PMID: 37148147 PMCID: PMC10365054 DOI: 10.1111/jvim.16734] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 04/21/2023] [Indexed: 05/07/2023] Open
Abstract
BACKGROUND Poor performance is a multifactorial syndrome of racehorses, commonly associated with subclinical disorders, which can be diagnosed by exercise testing. OBJECTIVES Describe the prevalence of medical causes of poor performance in Standardbreds unassociated with lameness, and evaluate their relationships with fitness variables measured by exercise treadmill test. ANIMALS Hospital population of 259 nonlame Standardbred trotters referred for poor performance. METHODS The horses' medical records were retrospectively reviewed. Horses underwent a diagnostic protocol including resting examination, plasma lactate concentration, treadmill test with continuous ECG and assessment of fitness variables, creatine kinase activity, treadmill endoscopy, postexercise tracheobronchoscopy, bronchoalveolar lavage (BAL), and gastroscopy. The prevalence of different disorders was evaluated, including cardiac arrhythmias, exertional myopathies, dynamic upper airway obstructions (DUAOs), exercise-induced pulmonary hemorrhage (EIPH), moderate equine asthma (MEA), and gastric ulcers (EGUS). The associations of these disorders with fitness variables were investigated individually and using multivariable models. RESULTS Moderate equine asthma and EGUS were the most common disorders, followed by EIPH, DUAOs, cardiac arrhythmias, and exertional myopathies. Hemosiderin score was positively correlated with BAL neutrophils, eosinophils, and mast cells; increased creatine kinase activity was associated with BAL neutrophilia, DUAOs, premature complexes, and squamous gastric disease. Treadmill velocity at a plasma lactate concentration of 4 mmol/L and at heart rate of 200 beats per minute was negatively affected by BAL neutrophilia, multiple DUAOs, exertional myopathies, and squamous gastric disease. CONCLUSIONS The multifactorial nature of poor performance was confirmed, with MEA, DUAOs, myopathies and EGUS representing the main diseases involved in fitness impairment.
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Affiliation(s)
- Chiara M. Lo Feudo
- Equine Sports Medicine Laboratory “Franco Tradati”, Department of Veterinary Medicine and Animal SciencesUniversità degli Studi di MilanoLodiItaly
| | - Luca Stucchi
- Equine Unit, Veterinary Teaching Hospital, Department of Veterinary Medicine and Animal SciencesUniversità degli Studi di MilanoLodiItaly
| | - Bianca Conturba
- Equine Unit, Veterinary Teaching Hospital, Department of Veterinary Medicine and Animal SciencesUniversità degli Studi di MilanoLodiItaly
| | - Giovanni Stancari
- Equine Unit, Veterinary Teaching Hospital, Department of Veterinary Medicine and Animal SciencesUniversità degli Studi di MilanoLodiItaly
| | - Enrica Zucca
- Equine Sports Medicine Laboratory “Franco Tradati”, Department of Veterinary Medicine and Animal SciencesUniversità degli Studi di MilanoLodiItaly
| | - Francesco Ferrucci
- Equine Sports Medicine Laboratory “Franco Tradati”, Department of Veterinary Medicine and Animal SciencesUniversità degli Studi di MilanoLodiItaly
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Decloedt A. Cardiac arrhythmias as a potential sign of systemic disease: Which laboratory tests are useful? EQUINE VET EDUC 2022. [DOI: 10.1111/eve.13547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- A. Decloedt
- Equine CardioTeam Department of Large Animal Internal Medicine Faculty of Veterinary Medicine Ghent University Merelbeke Belgium
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Kenchaiwong W, Sangpo P, Kusol A, Pontaema T, Lerdweeraphon W. The position of ground electrode affects electrocardiographic parameters in horses. Vet World 2022; 15:1107-1112. [PMID: 35698497 PMCID: PMC9178585 DOI: 10.14202/vetworld.2022.1107-1112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/23/2022] [Indexed: 11/17/2022] Open
Abstract
Background and Aim: Improper attachment of the grounding lead is one of the artifacts and causes difficulty in interpretation of ECG. This study aimed to examine the effects of the position of a ground electrode on electrocardiographic (ECG) parameters in horses. Materials and Methods: Sixteen Arabian horses without any cardiac problems were included in this study. The animals were divided into two groups, the base-apex lead method 1 (BA1 method) and the base-apex lead method 2 (BA2 method) with the reposition of the ground limb electrode to the xiphoid. ECG recordings (paper speed=25 mm/s and calibration=10 mm/mV) were performed to obtain six limb leads (leads I, II, III, aVR, aVL, and aVF). The amplitude and duration of P waves and QRS complexes, PR interval, QT interval, and T duration were analyzed. T wave morphology was observed. Heart rate was evaluated by using R-R interval in each recording. Results: Heart rate, P duration and amplitude, PR interval and T duration, and QRS duration and amplitude were not significantly different between the BA1 and the BA2 method, except that the BA2 method had a significantly higher QT interval than did the BA1 method (p<0.05). A higher significance of the percentage of coefficient of variation was seen on the P wave amplitude and the ORS amplitude in the BA1 method when compared to BA2 method (p<0.05). Conclusion: These data indicated that base-apex lead method with reposition of the ground limb electrode to the xiphoid can decrease variation of ECG configuration and might be useful for routine ECG evaluation and monitoring in horses. The limitation of this study was the evaluation of cardiac morphology and function by echocardiography to exclude cardiac problems. In further, the studies should examine the effect of breed, age, body weight, and sex on electrocardiography parameters in horses.
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Affiliation(s)
- Wootichai Kenchaiwong
- Applied Animal Physiology Research Unit, Faculty of Veterinary Science, Mahasarakham University, Thailand; Small Ruminant Research Unit, Faculty of Veterinary Science, Mahasarakham University, Thailand; Network Center for Animal Breeding and Omics Research, Khon Kaen University, Thailand
| | - Pamika Sangpo
- Faculty of Veterinary Science, Mahasarakham University, Thailand
| | - Anawach Kusol
- Faculty of Veterinary Science, Mahasarakham University, Thailand
| | - Theerapong Pontaema
- Applied Animal Physiology Research Unit, Faculty of Veterinary Science, Mahasarakham University, Thailand
| | - Wichaporn Lerdweeraphon
- Applied Animal Physiology Research Unit, Faculty of Veterinary Science, Mahasarakham University, Thailand; Small Ruminant Research Unit, Faculty of Veterinary Science, Mahasarakham University, Thailand
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ter Woort F, Dubois G, Tansley G, Didier M, Verdegaal E, Franklin S, Van Erck‐Westergren E. Validation of an equine fitness tracker: ECG quality and arrhythmia detection. Equine Vet J 2022; 55:336-343. [PMID: 35138653 PMCID: PMC10078706 DOI: 10.1111/evj.13565] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 01/16/2022] [Accepted: 02/02/2022] [Indexed: 12/01/2022]
Abstract
BACKGROUND Cardiac arrhythmias in exercising horses are the focus of much interest, both in terms of what is considered normal and potential associations with poor performance and sudden cardiac death. One barrier to performing large-scale studies is the lack of an easily applicable device, to allow recording of large numbers of high-quality exercising electrocardiograms (ECGs). The EquimetreTM is a new wearable device which records a single lead ECG, amongst other parameters. Validation of such wearable devices is essential before further studies are undertaken. OBJECTIVES To evaluate the quality of ECG using the EquimetreTM and compare arrhythmia detection during exercise with the reference TelevetTM system. STUDY DESIGN Prospective blinded clinical study. METHODS Simultaneous ECGs were recorded with both systems in 49 healthy horses during exercise. High intensity exercise (>40km/h) was performed by 29 racehorses, and lower intensity exercise for the remainder of the racehorses and show jumpers. Tracings were excluded if >10% artefact was present (duration of artefact relative to duration of exercise). For included ECGs, the duration of artefact was recorded and compared. ECGs were evaluated using Kubios premium software. Arrhythmia detection (yes/no) and arrhythmia classification (sinus arrhythmia, narrow complex of similar morphology to the sinus complexes or wide complex with a different morphology) were compared using Cohen's Kappa coefficient. RESULTS Nine TelevetTM ECGs and 3 EquimetreTM ECGs were excluded due to artefact >10%. TelevetTM ECGs included significantly more artefact during exercise than EquimetreTM ECGs (5% vs. 0.25% p<0.001). Arrhythmia analysis was performed on 38 horses' paired ECGs. The Kappa coefficient was excellent for arrhythmia detection (K=0.97) and arrhythmia classification (K=0.93). MAIN LIMITATIONS Relatively low numbers of horses with arrhythmias (n=21) were included. The ECG recordings only provided one lead, making arrhythmia classification challenging in some cases. CONCLUSIONS The Equimetre device provides a reliable ECG for arrhythmia detection during exercise. This system may be useful clinically and for future large-scale investigations into the occurrence and significance of exercising arrhythmias.
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Affiliation(s)
| | | | - Grace Tansley
- Equine Health and Performance CenterUniversity of Adelaide, Roseworthy CampusRoseworthySouth AustraliaAustralia
| | | | - Elisabeth‐Lidwien Verdegaal
- Equine Health and Performance CenterUniversity of Adelaide, Roseworthy CampusRoseworthySouth AustraliaAustralia
| | - Samantha Franklin
- Equine Health and Performance CenterUniversity of Adelaide, Roseworthy CampusRoseworthySouth AustraliaAustralia
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Hellings IR, Skjerve E, Karlstam E, Valheim M, Ihler CF, Fintl C. Racing-associated fatalities in Norwegian and Swedish harness racehorses: Incidence rates, risk factors, and principal postmortem findings. J Vet Intern Med 2022; 36:778-786. [PMID: 35060194 PMCID: PMC8965266 DOI: 10.1111/jvim.16364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 01/03/2022] [Accepted: 01/07/2022] [Indexed: 11/26/2022] Open
Abstract
Background There are no reports on the number of fatalities or causes of death in the Norwegian and Swedish harness racehorses. Objectives The incidence rates (IRs), risk factors, and postmortem findings in horses that died or were euthanized associated with racing between 2014 and 2019 were investigated. Animals Thirty‐eight Standardbreds and 10 Norwegian‐Swedish Coldblooded Trotters died or were euthanized associated with racing. A total of 816 085 race‐starts were recorded. Methods Incidence rates were calculated for both countries and horse breeds. Risk factors for sudden death were identified using a case‐control logistic model. Postmortem examinations were performed in 43 horses. Results The overall fatality IR was 0.059/1000 race‐starts. Traumatic injuries accounted for 14.5%, while sudden death for 85.5% of fatalities. Only minor differences between countries and breeds were recorded. The number of starts within the last 30 days increased the risk of sudden death (5 starts odds ratio (OR) 228.80, confidence interval (CI) 10.9‐4793). An opposite non‐linear effect was observed in number of starts the last 180 days (>10 starts OR 0.12, CI 0.02‐0.68). Seven horses were euthanized because of catastrophic injury. Acute circulatory collapse because of suspected cardiac or pulmonary failure or both was recorded in 30 horses, while major hemorrhage after vessel rupture was the primary cause of death in 10 cases. One horse collapsed and died but was not submitted for autopsy. Conclusions and Clinical Importance Comparatively low rates of catastrophic orthopedic fatalities were reported, while causes and IR of sudden death were similar to previous studies.
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Affiliation(s)
- Ingunn Risnes Hellings
- Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Ås, Norway
| | - Eystein Skjerve
- Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Ås, Norway
| | - Erika Karlstam
- Department of Pathology and Wildlife Diseases, The Swedish National Veterinary Institute, Uppsala, Sweden
| | - Mette Valheim
- Department of Pathology and High-Risk Pathogens, The Norwegian Veterinary Institute, Ås, Norway
| | - Carl Fredrik Ihler
- Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Ås, Norway
| | - Constanze Fintl
- Department of Companion Animal Clinical Sciences, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Ås, Norway
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Evaluation of Cardiac Arrhythmias before, during, and after Treadmill Exercise Testing in Poorly Performing Standardbred Racehorses. Animals (Basel) 2021; 11:ani11082413. [PMID: 34438870 PMCID: PMC8388799 DOI: 10.3390/ani11082413] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/06/2021] [Accepted: 08/13/2021] [Indexed: 11/16/2022] Open
Abstract
The incidence of significant arrhythmias in sport horses and knowledge about their exact influence on athletic performance need to be clarified. The aims of the present study are to report the prevalence of cardiac arrhythmias during maximal treadmill exercise in poorly performing Standardbreds, and to investigate the possible relationship of demographic, cardiac and performance indices on premature complexes (PCs). Electrocardiographic Holter recordings before, during and after treadmill exercise testing of 158 poorly performing Standardbreds were analyzed retrospectively. Fifty horses did not have any type of arrhythmia. One hundred and eight horses had at least one type of arrhythmia, such as sinus arrhythmia (8.2%), sinoatrial block (3.2%), second-degree atrioventricular block (33.5%), supraventricular PCs (7.6%), and ventricular PCs (48.1%). A multiple regression analysis showed weak evidence that the occurrence of premature complexes decreases as the minimum heart rate increases, and a tendency for these arrhythmias to increase with increasing age and maximum lactate concentration. Our results suggest that PCs are frequent in poorly performing Standardbred racehorses, but further studies are necessary to clarify their role and clinical significance.
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van Loon G, Smets P, Decloedt A. Cardiac arrhythmias in small and large animals: The more we learn, the more we realise how much we don't know. Vet J 2021; 273:105697. [PMID: 34148604 DOI: 10.1016/j.tvjl.2021.105697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 05/28/2021] [Indexed: 11/24/2022]
Affiliation(s)
- Gunther van Loon
- Equine Cardioteam, Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Pascale Smets
- Department of Small Animals, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Annelies Decloedt
- Equine Cardioteam, Department of Large Animal Internal Medicine, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
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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; 35:1111-1120. [PMID: 33604980 PMCID: PMC7995445 DOI: 10.1111/jvim.16063] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 01/25/2021] [Accepted: 02/02/2021] [Indexed: 12/23/2022] Open
Abstract
Background Atrial fibrillation (AF) impacts performance and horse and jockey safety. Understanding the outcomes of AF identified postrace will better inform regulatory policy. Hypothesis/Objectives To investigate the outcomes after episodes of AF identified postrace and determine whether affected horses are at increased risk of additional episodes compared to the general racing population. Animals Total of 4684 Thoroughbred racehorses. Methods Race records for Thoroughbred horses racing in Hong Kong from 2007 to 2017 were reviewed. Horses that performed below expectation were examined by cardiac auscultation and ECG. Incidence and recurrence of AF were compared between horses with and without a history of AF and between horses with paroxysmal and persistent episodes using Fisher's exact test. Results There were 96 135 race starts during the study. Atrial fibrillation was identified in 4.9% of horses, with an overall incidence of 2.7 episodes per 1000 starts. The incidence of AF in horses after any previous episode (12.8 per 1000 starts) was higher than for horses with no previous episode (2.4 per 1000 starts; odds ratio [OR], 5.3; 95% confidence interval [CI], 3.8‐7.6). Recurrence was seen in 64% of horses previously treated for persistent AF, which was higher than recurrence in horses with paroxysmal AF (23%; OR, 5.9; 95% CI, 1.6‐21.2). Median duration between episodes was 343 days (range, 34‐1065). Conclusions and Clinical Importance Thoroughbreds are at increased risk of recurrent AF after both paroxysmal and persistent episodes, but the duration of time between episodes varies widely. These findings support a substantial burden of AF among individual Thoroughbred racehorses.
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Affiliation(s)
- Laura C Nath
- School of Animal & Veterinary Sciences, University of Adelaide, Roseworthy, South Australia, Australia
| | - Adrian D Elliott
- Centre for Heart Rhythm Disorders, Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | - Joe Weir
- Hong Kong Jockey Club, Veterinary Clinical Services, Equine Hospital, Hong Kong SAR, Hong Kong
| | - Peter Curl
- Veterinary Regulation, Hong Kong Jockey Club, Hong Kong SAR, Hong Kong
| | | | - Samantha Franklin
- School of Animal & Veterinary Sciences, University of Adelaide, Roseworthy, South Australia, Australia
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