In sport horses, the exact influence of premature depolarizations (PDs) on athletic performance is still not well defined [1-5]. The aims of the present study are to report the prevalence of the most common cardiac arrhythmias detected during treadmill exercise in poorly performing Standardbreds, and to investigate possible differences, regarding some demographic, cardiac and performance indices, between horses with or without PDs. The study was conducted on 158 poorly performing Standardbred trotters, in which obvious causes of poor performance at rest were ruled out and plasma lactate curve threshold during incremental exercise test on a high-speed treadmill , and simultaneous Holter recording , were obtained. Statistical analyses (descriptive, exploratory, and multiple logistic regression) were performed to verify possible differences between horses with or without PDs regarding sex, age, minimum and maximum heart rate, difference between maximum heart rate and heart rate at 1 minute of recovery, maximum speed, maximum plasma lactate concentration, and time to fatigue. Fifty horses did not show any type of arrhythmia while 108 subjects had at least one type of arrhythmia. Supraventricular PDs (27/158, 17.1%) and ventricular PDs (66/158, 41.8%) were mainly observed during the first minute post exercise and in a lesser number of subjects during peak exercise. PDs were mainly observed as single or isolated premature beats, but also as pairs (24 horses) and as paroxysm of supraventricular and/or ventricular tachycardia (4 cases). Univariate statistical analysis (exploratory analyses) showed no differences regarding demographic, cardiac and performance indices, between horses with or without PDs; multiple regression analysis showed weak or borderline evidence of dependence of PDs occurrence from age (P=0.08), minimum heart rate (P=0.04), and maximum plasma lactate concentration (P=0.08). Our data suggest that PDs are frequently recorded in poorly performing Standardbred racehorses, but the results obtained in the present study did not clarify their role and clinical significance. Nevertheless, we would like to suggest that the presence of PDs in racehorses, recorded during and after strenuous exercise, should be further investigated.
|Titolo:||Evaluation of cardiac arrhythmias before, during and after treadmill exercise testing in poorly performing standardbred racehorses|
ZUCCA, ENRICA (Corresponding)
|Settore Scientifico Disciplinare:||Settore VET/08 - Clinica Medica Veterinaria|
|Data di pubblicazione:||20-giu-2018|
|Tipologia:||Book Part (author)|
|Appare nelle tipologie:||03 - Contributo in volume|