TY - JOUR

T1 - Atrial fibrillation as a risk factor for exercise-induced pulmonary haemorrhage following a standardised exercise test

AU - Hansen, Sanni

AU - Otten, Nina D.

AU - Nissen, Sarah D.

AU - Carstensen, Helena

AU - Hopster-Iversen, Charlotte

AU - Fjeldborg, Julie

AU - Staun, Sophie H.

AU - Fenner, Merle

AU - Hesselkilde, Eva M.

AU - Buhl, Rikke

N1 - Publisher Copyright: © 2023 The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.

PY - 2024

Y1 - 2024

N2 - Background: Atrial fibrillation (AF) has been proposed as a risk factor for exercise-induced pulmonary haemorrhage (EIPH) due to increased pressure in the left atrium. Objective: To evaluate if AF was associated with EIPH following a standardised exercise test (SET) to fatigue. Study design: Two-arm controlled experiment. Methods: Ten untrained Standardbred mares mean (standard deviation [SD]) age 6 (2) years performed a SET on the treadmill in sinus rhythm (SR) (SET1) and 25–44 days after induction of self-sustained AF (SET2). AF was induced by tachypacing using a pacing device. Endoscopy, including tracheal wash and bronchoalveolar lavage (BAL), was performed 48–72 h before and 24 h after the two SETs. In addition, endoscopic grading of tracheal blood was performed 2 h after each SET. Results: After SET1, none of the horses showed blood in the trachea, and two horses showed erythrophagocytosis. Following SET2, two horses had grade 1 blood in the trachea and free erythrocytes and erythrophagocytosis in the BAL, while another two horses had erythrophagocytosis in the BAL. In SET2, the overall performance on the treadmill was decreased with a lower maximum velocity (SET1 10.3 ± 0.8 m/s vs. SET2 8.9 ± 0.9 m/s, p = 0.004), a higher heart rate (284 ± 21 vs. 221 ± 18 bpm, p = 0.003) and more abnormal QRS complexes (p < 0.001) compared with SET1. Conclusions: Two horses showed signs of EIPH, resulting in visible blood in the trachea, when exercising in AF compared with SR. However, a possible link between EIPH, pulmonary pressure and AF needs to be further elucidated.

AB - Background: Atrial fibrillation (AF) has been proposed as a risk factor for exercise-induced pulmonary haemorrhage (EIPH) due to increased pressure in the left atrium. Objective: To evaluate if AF was associated with EIPH following a standardised exercise test (SET) to fatigue. Study design: Two-arm controlled experiment. Methods: Ten untrained Standardbred mares mean (standard deviation [SD]) age 6 (2) years performed a SET on the treadmill in sinus rhythm (SR) (SET1) and 25–44 days after induction of self-sustained AF (SET2). AF was induced by tachypacing using a pacing device. Endoscopy, including tracheal wash and bronchoalveolar lavage (BAL), was performed 48–72 h before and 24 h after the two SETs. In addition, endoscopic grading of tracheal blood was performed 2 h after each SET. Results: After SET1, none of the horses showed blood in the trachea, and two horses showed erythrophagocytosis. Following SET2, two horses had grade 1 blood in the trachea and free erythrocytes and erythrophagocytosis in the BAL, while another two horses had erythrophagocytosis in the BAL. In SET2, the overall performance on the treadmill was decreased with a lower maximum velocity (SET1 10.3 ± 0.8 m/s vs. SET2 8.9 ± 0.9 m/s, p = 0.004), a higher heart rate (284 ± 21 vs. 221 ± 18 bpm, p = 0.003) and more abnormal QRS complexes (p < 0.001) compared with SET1. Conclusions: Two horses showed signs of EIPH, resulting in visible blood in the trachea, when exercising in AF compared with SR. However, a possible link between EIPH, pulmonary pressure and AF needs to be further elucidated.

KW - arrhythmia

KW - bronchoalveolar lavage

KW - epistaxis

KW - equine asthma

KW - horse

KW - performance

U2 - 10.1111/evj.13995

DO - 10.1111/evj.13995

M3 - Journal article

C2 - 37654233

AN - SCOPUS:85169325903

VL - 56

SP - 552

EP - 561

JO - Equine Veterinary Journal

JF - Equine Veterinary Journal

SN - 0425-1644

IS - 3

ER -