Among Kaiser Permanente Northern California (KPNC) health plan members, age ≥16 years, with recent syncope and presyncope undergoing emergency department (ED) management with a point-of-care clinical decision support (CDS) tool, how well does the Canadian Syncope Risk Score predict 30-day serious outcomes that were not evident during index ED evaluation?

Inclusion Criteria:

• Age ≥16y
• Member of Kaiser Permanente Northern California (KPNC) health plan
• Presentation to the ED with an ED diagnosis of recent syncope or presyncope (<24h) without a serious etiology identified during the initial ED diagnostic assessment, that is, patients with unexplained syncope.
• Subjects who meet criteria will be identified electronically within the CDS tool in the electronic health record.

Exclusion Criteria:

• Age <16 years old
• Non-members of KPNC
• Patients with obvious witnessed seizure, prolonged loss of consciousness (>5 minutes), post-traumatic loss of consciousness, and new mental status changes
• Patients requiring hospitalization for traumatic injuries (e.g., syncope leading to motorized vehicle collision), because their outcomes may be related to trauma rather than syncope
• Patients with impaired communication capacity, e.g., intoxication, language barriers, and dementia.

Patients presenting to KPNC emergency departments with eligibility criteria