Broadbent J C, Nishimura R A, Harrison C E
Mayo Clin Proc. 1983 Sep;58(9):620-3.
Reentrant tachycardia occurred after implantation of an atrial synchronous ventricular-inhibited pacemaker in a patient with bradycardia caused by second-degree (Mobitz II) atrioventricular block. Despite the presence of antegrade atrioventricular block, intact ventriculoatrial conduction was present at a cycle length that exceeded the atrial refractory period of the pacemaker. Consequently, a reentrant or "endless-loop" tachycardia occurred. Application of a magnet terminated the tachycardia. Because the episodes were frequent and could not be prevented by medication, the pacemaker was reprogrammed to a ventricular-inhibited mode. All candidates for atrial synchronous pacing should undergo an appropriate electrophysiologic study preoperatively.
在一名因二度（莫氏Ⅱ型）房室传导阻滞导致心动过缓的患者植入心房同步心室抑制型起搏器后，出现了折返性心动过速。尽管存在房室前向传导阻滞，但在超过起搏器心房不应期的周期长度时，仍存在完整的室房传导。因此，发生了折返性或“无休止环”性心动过速。应用磁铁终止了心动过速。由于发作频繁且药物无法预防，起搏器被重新程控为心室抑制模式。所有心房同步起搏的候选者术前均应进行适当的电生理检查。
