Sudden death in sport and riding horses during and immediately after exercise: A case series.

BACKGROUND Sudden death affects the health of horses, the safety of riders and the public perception of animal welfare during equestrian events. OBJECTIVES To describe the signalment, clinical history, sudden death episode, rider injuries and causes of sudden death during exercise or closely thereafter in sport and pleasure riding horses. STUDY DESIGN Retrospective case series based on an online questionnaire. METHODS An online questionnaire was distributed to the veterinary and equestrian community. Connections of animals reported in the press to have died suddenly were sent the survey. Responses were analysed to obtain information. RESULTS Fifty-seven cases met inclusion criteria with enough information to be analysed. The most common discipline was eventing (n = 23, 40.4%), and the most common breed involved was Thoroughbred (n = 23, 40.4%). Forty-one (71.9%) horses collapsed during exercise, and 16 (28.1%) shortly thereafter. Twenty-four (42.1%) horses died during or near the time of competition and 33 (57.9%) during or near the time of training or a pleasure ride. In 16 (28.1%) horses, the cause of death was known or strongly suspected based on a post-mortem result, and a cardiovascular origin was reported in 13 of these 16 cases. Riders were injured in 13 (22.8%) cases, and injuries to their extremities were the most frequent. MAIN LIMITATIONS There is potential for misdiagnosis and recall and selection bias, and in the absence of data on the total number of horses engaged in equestrian sports and riding, prevalence cannot be calculated. CONCLUSIONS Sudden death occurred in many types of equestrian sports and in riding horses. Death outside competition was more common suggesting that registries based on reports from official veterinarians underestimate the magnitude of this problem. Rider injuries were not uncommon when ridden horses collapsed and died. A definitive diagnosis for the cause of death was not commonly achieved and cardiovascular origin was the most common where a diagnosis was proposed by survey respondents

Cardiovascular variables in eventing and endurance horses over a season

Introduction The objectives of this study were to describe the changes in clinical cardiovascular examination variables over a competition season in groups of competitive eventing and endurance horses and to compare these findings to non-competitive controls of the same breeds. Animals This study included two eventing horses, 11 endurance horses, and 13 eventing and seven endurance control breed-matched horses. Materials and methods Cardiovascular examinations were performed before starting the competition season, in the middle and at the peak/end of the competition season. Examinations included auscultation of the heart; M-mode echocardiographic measurements and calculated values; left atrial, pulmonary artery, and aortic diameters; color flow Doppler; exercise electrocardiograms (ECG) measuring peak heart rates and quantifying premature complexes; and 24-h continuous ECGs quantifying premature complexes per hour. Results Auscultation, echocardiograms, arrhythmias during exercise, and 24-h continuous ECGs did not change significantly throughout the season (p > 0.05 for all variables). Conclusion Cardiovascular examination variables of eventing and endurance horses throughout a competition season are reported here for the first time. Although the present study did not reveal significant changes, data should be interpreted carefully as only a small number of horses were examined