Bottom line: Patients who present to the emergency department with near syncope and syncope are likely to have similar prevalence, etiology, prognosis, critical interventions, and adverse outcomes. Patients with near syncope are less likely to be admitted.
Grossman, Shamai A, et al. “Do outcomes of near syncope parallel syncope?” The American journal of emergency medicine 30.1 (2012):203-6.
Study included 244 patients who presented to the emergency department (ED) with near syncope; “follow-up was achieved in 242 (99%). Emergency department hospitalization or 30-day adverse outcomes occurred in 49 (20%) of 244 compared with 68 (23%) of 293 of patients with syncope (P = .40). The most common adverse outcomes/critical interventions were hemorrhage (n = 6), bradydysrhythmia (n = 6), alteration in antidysrhythmics (n = 6), and sepsis (n = 10). Of patients with near syncope, 49% were admitted compared with 69% with syncope (P = .001). Patients with near syncope are as likely those with syncope to experience critical interventions or adverse outcomes; however, near-syncope patients are less likely to be admitted.”
Greve, Yvonne, et al. “The prevalence and prognostic significance of near syncope and syncope: a prospective study of 395 cases in an emergency department (the SPEED study).” Deutsches Ärzteblatt international 111.12 (2014):197-204.
This is a prospective study of 395 patients seen in ED for syncope or near syncope who were followed up at 30 days and 6 months. Those with “near-syncope do not differ to any large extent from patients with syncope with respect to the features studied” (prevalence, etiology, prognosis).