In general , syncope is defined by a brief loss of consciousness ( fainting ) or by dimmed vision and feeling uncoordinated , confused , and lightheaded 一般说来，晕厥的定义是意识的短暂丧失(晕倒)或两眼发黑，感到共济失调、意识迷糊或头昏眼花。
Syncope is a brief loss of consciousness with collapse resulting from transient brain dysfunction based on decreased blood flow or neurologic insult 晕厥是暂时性意识丧失并跌倒，它是因为血流减少或神经损伤而造成一过性大脑功能失调而引起的。
As specific physiologic triggers have not been clearly identified , it is difficult to identify those patients who may be at risk for vasovagal syncope 因为血管迷走神经性晕厥的特殊生理机制尚未明了，因此，很难鉴别可能存在血管迷走神经性晕厥的患者。
Older age ( > 60 years ) is more highly associated with arrhythmias , orthostatic hypotension , medication side - effects , and situational ( e . g . , micturition ) syncope 老龄病人（ 60岁）与心律不齐、直立性低血压、药物副作用和环境性（如排尿）晕厥关联更大。
Although earlier work noted that vasodilation promoted the onset of syncope , more recent work has suggested that syncope occurs prior to vasodilation ( 1 ) 虽然早期研究表明，血管扩张诱发迷走性晕厥，但是最近更多研究表明迷走性晕厥出现在血管扩张之前[ 1 ] 。
Krahn ad , kleiingj , norrisc et al . the etiology of syncope in patients with negative tilt table and electrophysiological testing . circu lation , 1995 , 92 ( 7 ) : 1819 任自文、吴宁、陈孟扬,等,倾斜试验用于诊断血管迷走神性晕厥的建议.中华心血管病杂志, 1998 , 26 ( 5 ) : 325
Tilt table testing is indicated for unexplained , recurrent syncope when arrhythmia or organic heart disease is excluded and neurocardiogenic syncope is suspected 在排除心律失常或器质性心脏病并怀疑有神经心源性晕厥时，就需要进行倾斜试验，以对不明因复发性晕厥作出诊断。
The concerned pacemakers may not function properly without warning and can result in serious health complications , such as syncope which required emergency hospitalization 有关的起搏器可能会在没有预警下丧失功能，因而引致严重的后果，例如病人可能会昏厥而需即时入院。
