van Bavel Joanne J A, Beekman Henriëtte D M, Schot Arend, Wouters Philippe C, van Emst Maarten G, Takken Tim, van der Heyden Marcel A G, Vos Marc A
Department of Medical Physiology, University Medical Center Utrecht, Utrecht, the Netherlands.
Department of Clinical Sciences, Division of Anatomy and Physiology, Faculty of Veterinary Medicine, Utrecht University, the Netherlands.
Int J Cardiol Heart Vasc. 2023 Jan 3;44:101169. doi: 10.1016/j.ijcha.2022.101169. eCollection 2023 Feb.
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.
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.
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, and signs of desaturation and acidification in venous blood.
Dogs with limited remodeling after AV block have a reduced exercise tolerance, which is reflected in changes in cardiorespiratory parameters.
在清醒状态下诱导房室传导阻滞（AV 阻滞）后不同重塑阶段标准化的临床前模型适用于评估改良心脏装置。我们研究了犬只诱导 AV 阻滞后三个不同时间点的运动诱导心肺参数。
将杂种犬（n = 12）置于坡度为 10%的跑步机上，执行中等强度运动方案（以 6 km/h 的速度跑步 10 分钟）。犬只在窦性心律（SR）、AV 阻滞后两天（AVB2d，重塑开始）、三周（CAVB3）和六周（CAVB6，重塑完成）时跑步。
所有犬只在 SR、CAVB3 和 CAVB6 时均完成了运动方案，而 AVB2d 时 12 只犬中有 6 只未能完成运动方案。与 SR 相比（静息时 100 ± 29 bpm，运动时 162 ± 28 bpm，p < 0.05），所有 AV 阻滞时间点的心房率均较高（静息时 126 ± 20 至 141 ± 19 bpm，运动时 221 ± 10 至 231 ± 13 bpm）。运动时，每搏输出量从 SR 时的 66 ± 15 ml 增加到 AVB2d 时的 96 ± 21 ml（p < 0.05）、CAVB3 时的 91 ± 13 ml（p < 0.05）和 CAVB6 时的 85 ± 24 ml，但未能补偿 AV 阻滞引起的心动过缓。因此，与 SR 相比，AV 阻滞后的心输出量较低。在 AVB2d 运动的犬只表现出最多的心律失常事件、最低的 VO，以及静脉血中去饱和和酸化的迹象。
AV 阻滞后重塑有限的犬只运动耐量降低，这反映在心肺参数的变化上。
