Department of Neurology & Clinical Neurophysiology, Leiden University Medical Centre, Leiden, The Netherlands.
Department of Neurology, Franciscus Gasthuis en Vlietland Hospital, PO 215, 3100 AE Rotterdam/Schiedam, The Netherlands.
Europace. 2021 Sep 8;23(9):1487-1492. doi: 10.1093/europace/euab044.
We describe five patients with syncope caused by a complete atrioventricular block (AVB) while they were bending forward, not rising after bending, and aim to describe the occurrence and the association between bending forward and AVB.
In two patients, bending forward was the exclusive trigger for syncope, while in the remaining three, other postural changes (sitting down, standing up, and exertion) could also provoke syncope. Complete AVB as the cause of syncope was documented using ECG monitoring in two cases and an implantable loop recorder in the other three. Ectopic beats without preceding sinus slowing occurred before syncope in four cases. Two cases had a left bundle branch block. All patients responded favourably to cardiac pacing.
This is the first case series on complete AVB provoked by bending forward. Syncope during bending forward should suggest a search for an AVB. Arguments in favour of a vagal mechanism were syncope triggered by bending forward, and that other triggers could also evoke syncope. However, the absence of sinus slowing before syncope in some cases and the fact that bending forward did not seem to provoke reflex syncope without AVB, cast doubts on a reflex mechanism. There were also arguments favouring conduction disorder: i.e. ectopic beats before syncope and pre-existing conduction disturbances in two cases. The cases are reminiscent of paroxysmal AVB. Discrimination between paroxysmal AVB and vagal AVB is important because a pacemaker is warranted in arrhythmic complete AVB, while the benefit is limited or absent in reflex AVB.
我们描述了 5 例因完全性房室传导阻滞（AVB）而导致的晕厥患者，这些患者在弯腰时发生晕厥，而不是在弯腰后起身时发生晕厥，并旨在描述弯腰与 AVB 之间的发生机制和相关性。
在 2 例患者中，弯腰是晕厥的唯一触发因素，而在另外 3 例患者中，其他体位变化（坐下、站立和用力）也可引起晕厥。在 2 例患者中，使用心电图监测记录晕厥时的完全性 AVB，而在另外 3 例患者中使用植入式循环记录仪记录晕厥时的完全性 AVB。在 4 例患者中，晕厥前出现无窦性心动过缓的异位搏动。2 例患者存在左束支传导阻滞。所有患者对心脏起搏治疗反应良好。
这是首例因弯腰而导致的完全性 AVB 晕厥的病例系列研究。弯腰时发生晕厥应提示寻找 AVB 的病因。支持迷走神经机制的论据是晕厥由弯腰触发，且其他触发因素也可引发晕厥。然而，在一些情况下，晕厥前无窦性心动过缓，且弯腰似乎不会引起无 AVB 的反射性晕厥，这对反射机制提出了质疑。也有一些支持传导障碍的论据：即晕厥前存在异位搏动和 2 例患者存在预先存在的传导障碍。这些病例类似于阵发性 AVB。区分阵发性 AVB 和迷走神经性 AVB 非常重要，因为心律失常性完全性 AVB 需要起搏器治疗，而反射性 AVB 的获益有限或不存在。
