Sra J, Singh B, Blanck Z, Dhala A, Akhtar M
Electrophysiology Laboratory of Sinai Samaritan and St. Luke's Medical Centers, University of Wisconsin Medical School-Milwaukee Clinical Campus, USA.
J Cardiovasc Electrophysiol. 1998 Feb;9(2):203-7. doi: 10.1111/j.1540-8167.1998.tb00901.x.
Neurocardiogenic (vasovagal) syncope is characterized by hypotension and bradycardia. The presence of sinus tachycardia along with AV block during syncope in patients with neurocardiogenic syncope has not been described previously.
Two female patients (18 and 16 years old) with recurrent syncope and documented sinus tachycardia at the time of syncope are described. Patient 1 had recurrent episodes of syncope. During one of these episodes, which occurred while she was being monitored, sinus tachycardia along with high-grade AV block was seen at the time of syncope and hypotension. Patient 2 had a history of recurrent syncope and seizure. During one of these episodes, she was documented to have ventricular asystole lasting for about 39 seconds. The sinus rate was 480 msec at the beginning, before slowing down to 960 msec prior to restoration of sinus rhythm with 1:1 AV conduction. The same scenario was repeated during head-up tilt testing. Both patients were treated successfully with oral disopyramide and, during a follow-up of 28 months and 9 months, have remained symptom-free.
Sinus acceleration along with high-grade AV block during syncope and hypotension can occur in some patients with neurocardiogenic syncope. The exact mechanism of this phenomenon is unclear.
神经心源性（血管迷走性）晕厥的特征是低血压和心动过缓。神经心源性晕厥患者在晕厥期间出现窦性心动过速伴房室传导阻滞的情况此前尚未见报道。
描述了两名患有复发性晕厥且在晕厥时记录到窦性心动过速的女性患者（分别为18岁和16岁）。患者1有复发性晕厥发作。在其中一次发作期间，即在对她进行监测时，在晕厥和低血压发生时观察到窦性心动过速伴高度房室传导阻滞。患者2有复发性晕厥和癫痫病史。在其中一次发作期间，记录到她的心室停搏持续约39秒。开始时窦性心率为480毫秒，在恢复1:1房室传导的窦性心律之前减慢至960毫秒。在直立倾斜试验期间重复出现相同情况。两名患者均口服丙吡胺治疗成功，在28个月和9个月的随访期间均无症状。
一些神经心源性晕厥患者在晕厥和低血压期间可出现窦性加速伴高度房室传导阻滞。这一现象的确切机制尚不清楚。
