This study was designed to validate the "San Francisco Syncope Rule". This set of rules was derived by Quinn et. al. to help guide the treatment of patients evaluated in the Emergency Department who had an episode of syncope (passed out) or near syncope (almost passed out). A rule that considers patients with an abnormal ECG, a complaint of shortness of breath, hematocrit less than 30%, systolic blood pressure less than 90 mm Hg, or a history of congestive heart failure was shown predict with a good degree of accuracy which patients would have an adverse event and require admission.

This study was designed to validate the "San Francisco Syncope Rule". This set of rules was derived by Quinn et. al. to help guide the treatment of patients evaluated in the Emergency Department who had an episode of syncope or near syncope.

A rule that considers patients with an abnormal ECG, a complaint of shortness of breath, hematocrit less than 30%, systolic blood pressure less than 90 mm Hg, or a history of congestive heart failure was shown predict with a good degree of accuracy which patients would have an adverse event/serious outcome and require admission. Serious outcomes include the following: death,myocardial infarction, arrhythmia, pulmonary embolism, stroke, subarachnoid hemorrhage, significant hemorrhage, or any condition causing a return ED visit and hospitalization for a related event.

In Quinn's derivation trial, the sensitivity of the rule was 96%.

Inclusion Criteria: Acute syncope or near syncope as a reason for the ED visit

Exclusion Criteria: Altered mental status, alcohol or illicit drug-related loss of consciousness, Definite seizure, Transient loss of consciousness caused by head trauma