TY - JOUR
T1 - Remodeling in the AV block dog is essential for tolerating moderate treadmill activity
AU - van Bavel, Joanne J.A.
AU - Beekman, Henriëtte D.M.
AU - Schot, Arend
AU - Wouters, Philippe C.
AU - van Emst, Maarten G.
AU - Takken, Tim
AU - van der Heyden, Marcel A.G.
AU - Vos, Marc A.
N1 - © 2022 The Authors.
PY - 2023/2
Y1 - 2023/2
N2 - BACKGROUND: A preclinical model standardized at different remodeling stages after AV block induction in awake state is suitable for the evaluation of improved cardiac devices. We studied exercise-induced cardiorespiratory parameters at three different timepoints after inducing AV block in dogs.METHODS: Mongrel dogs (n = 12) were placed on a treadmill with a 10% incline and performed a moderate exercise protocol (10-minute run at 6 km/h). Dogs ran at sinus rhythm (SR), at two days (AVB2d, initiation of remodeling), three weeks (CAVB3) and six weeks (CAVB6, completed remodeling) after AV block.RESULTS: All dogs completed the exercise protocol at SR, CAVB3 and CAVB6, while 6/12 dogs at AVB2d failed to complete the exercise protocol. The atrial rate was higher at all AV block timepoints (126 ± 20 to 141 ± 19 bpm at rest and 221 ± 10 to 231 ± 13 bpm during exercise) compared to SR (100 ± 29 bpm at rest and 162 ± 28 bpm during exercise, p < 0.05). Upon exercise, stroke volume increased from 66 ± 15 ml at SR, to 96 ± 21 ml at AVB2d (p < 0.05), 91 ± 13 ml at CAVB3 (p < 0.05) and 85 ± 24 ml at CAVB6 but failed to compensate for the AV block-induced bradycardia. Therefore, cardiac output was lower after AV block compared to SR. Exercising dogs at AVB2d showed most arrhythmic events, lowest VO
2, and signs of desaturation and acidification in venous blood.
CONCLUSION: Dogs with limited remodeling after AV block have a reduced exercise tolerance, which is reflected in changes in cardiorespiratory parameters.
AB - BACKGROUND: A preclinical model standardized at different remodeling stages after AV block induction in awake state is suitable for the evaluation of improved cardiac devices. We studied exercise-induced cardiorespiratory parameters at three different timepoints after inducing AV block in dogs.METHODS: Mongrel dogs (n = 12) were placed on a treadmill with a 10% incline and performed a moderate exercise protocol (10-minute run at 6 km/h). Dogs ran at sinus rhythm (SR), at two days (AVB2d, initiation of remodeling), three weeks (CAVB3) and six weeks (CAVB6, completed remodeling) after AV block.RESULTS: All dogs completed the exercise protocol at SR, CAVB3 and CAVB6, while 6/12 dogs at AVB2d failed to complete the exercise protocol. The atrial rate was higher at all AV block timepoints (126 ± 20 to 141 ± 19 bpm at rest and 221 ± 10 to 231 ± 13 bpm during exercise) compared to SR (100 ± 29 bpm at rest and 162 ± 28 bpm during exercise, p < 0.05). Upon exercise, stroke volume increased from 66 ± 15 ml at SR, to 96 ± 21 ml at AVB2d (p < 0.05), 91 ± 13 ml at CAVB3 (p < 0.05) and 85 ± 24 ml at CAVB6 but failed to compensate for the AV block-induced bradycardia. Therefore, cardiac output was lower after AV block compared to SR. Exercising dogs at AVB2d showed most arrhythmic events, lowest VO
2, and signs of desaturation and acidification in venous blood.
CONCLUSION: Dogs with limited remodeling after AV block have a reduced exercise tolerance, which is reflected in changes in cardiorespiratory parameters.
KW - AV block dog model
KW - Cardiorespiratory changes
KW - Exercise
KW - Remodeling
KW - Treadmill
UR - http://www.scopus.com/inward/record.url?scp=85145991264&partnerID=8YFLogxK
U2 - 10.1016/j.ijcha.2022.101169
DO - 10.1016/j.ijcha.2022.101169
M3 - Article
C2 - 36632286
AN - SCOPUS:85145991264
SN - 2352-9067
VL - 44
JO - IJC Heart and Vasculature
JF - IJC Heart and Vasculature
M1 - 101169
ER -