TY - JOUR
T1 - Effect of induced chronic atrial fibrillation on exercise performance in Standardbred trotters
AU - Buhl, Rikke
AU - Carstensen, Helena
AU - Hesselkilde, Eva Zander
AU - Klein, Bjørg Zinkernagel
AU - Hougaard, Karen Margrethe
AU - Ravn, Kirsten Bomberg
AU - Loft-Andersen, Ameli Victoria
AU - Fenner, Merle Friederike
AU - Pipper, Christian
AU - Jespersen, Thomas
PY - 2018
Y1 - 2018
N2 - Background: Atrial fibrillation (AF) is the most common arrhythmia affecting performance in horses. However, no previous studies have quantified the performance reduction in horses suffering from AF. Objectives: To quantify the effect of AF on maximum velocity (Vmax), maximum heart rate (HRmax), heart rate recovery (T100), hematologic parameters and development of abnormal QRS complexes. Animals: Nine Standardbred trotters. Methods: Two-arm controlled trial. Six horses had AF induced by means of a pacemaker and 3 served as sham-operated controls. All horses were subjected to an exercise test to fatigue before (SET1) and after (SET2) 2 months of AF or sham. The Vmax and HRmax were assessed using a linear mixed normal model. Abnormal QRS complexes were counted manually on surface ECGs. Results: Atrial fibrillation resulted in a 1.56 m/sec decrease in Vmax (P <.0001). In the AF group, HRmax ± SD increased from 226 ± 11 bpm at SET1 to 311 ± 27 bpm at SET 2. The AF group had higher HRmax at SET2 compared with controls (P <.0001), whereas no difference between the control and AF groups was observed at SET1 (P =.96). Several episodes of wide complex tachycardia were observed during exercise in 3 of the AF horses during SET2. Conclusions and Clinical Importance: Atrial fibrillation resulted in a significant reduction in performance, an increase in HR and development of abnormal QRS complexes during exercise, which may be a risk factor for collapse or sudden cardiac death.
AB - Background: Atrial fibrillation (AF) is the most common arrhythmia affecting performance in horses. However, no previous studies have quantified the performance reduction in horses suffering from AF. Objectives: To quantify the effect of AF on maximum velocity (Vmax), maximum heart rate (HRmax), heart rate recovery (T100), hematologic parameters and development of abnormal QRS complexes. Animals: Nine Standardbred trotters. Methods: Two-arm controlled trial. Six horses had AF induced by means of a pacemaker and 3 served as sham-operated controls. All horses were subjected to an exercise test to fatigue before (SET1) and after (SET2) 2 months of AF or sham. The Vmax and HRmax were assessed using a linear mixed normal model. Abnormal QRS complexes were counted manually on surface ECGs. Results: Atrial fibrillation resulted in a 1.56 m/sec decrease in Vmax (P <.0001). In the AF group, HRmax ± SD increased from 226 ± 11 bpm at SET1 to 311 ± 27 bpm at SET 2. The AF group had higher HRmax at SET2 compared with controls (P <.0001), whereas no difference between the control and AF groups was observed at SET1 (P =.96). Several episodes of wide complex tachycardia were observed during exercise in 3 of the AF horses during SET2. Conclusions and Clinical Importance: Atrial fibrillation resulted in a significant reduction in performance, an increase in HR and development of abnormal QRS complexes during exercise, which may be a risk factor for collapse or sudden cardiac death.
KW - arrhythmia
KW - atrial fibrillation
KW - cardiology
KW - exercise
KW - heart rate
KW - horse
KW - performance
U2 - 10.1111/jvim.15137
DO - 10.1111/jvim.15137
M3 - Journal article
C2 - 29749082
AN - SCOPUS:85046769601
SN - 0891-6640
VL - 32
SP - 1410
EP - 1419
JO - Journal of Veterinary Internal Medicine
JF - Journal of Veterinary Internal Medicine
IS - 4
ER -