In a study of 822 patients presenting with syncope, the most common cause was vasovagal, or neurocardiogenic, syncope (28.7%).1 In vasovagal disorders, syncope results from sudden reflex-mediated hypotension and/or bradycardia. Some common causes of vasovagal syncope include coughing, urination, defecation, anxiety, prolonged standing, and alcohol use. Even after good history, physical examination, and ECG, the cause of syncope remained unknown in 36.6% of patients.1 Despite the initial predominance of unknown causes after initial assessment, it is important to note that a cause of syncope is eventually identified in over 90% of cases.2
- Vasovagal syncope.
1. Soteriades ES, Evans JC, Larson MG, et al. Incidence and prognosis of syncope. N Engl J Med 2002;347:878-85.
2. Kapoor WN, McAdams DJ. Syncope. In: Wachter RM, Goldman L, Hollander H, editors. Hospital medicine. 2nd ed. Philadelphia: Lippincott Williams & Wilkins; 2005:
Click here to return to the questions