External validation of the San Francisco Syncope Rule

Area of Science:

• Emergency Medicine
• Clinical Decision Rules
• Cardiology

Background:

• The San Francisco Syncope Rule is a clinical decision tool designed to identify patients with syncope at risk for serious clinical events.
• External validation is crucial to assess the generalizability and reliability of clinical decision rules in new patient cohorts.
• Accurate risk stratification in syncope patients presenting to the emergency department is essential for appropriate management and resource allocation.

Purpose of the Study:

• To externally validate the diagnostic accuracy of the San Francisco Syncope Rule in identifying syncope patients who will experience a 7-day serious clinical event.
• To assess the rule's performance in predicting serious clinical events not initially identified in the emergency department evaluation.

Main Methods:

• Prospective enrollment of syncope or near-syncope patients in a single academic emergency department.
• Systematic recording of San Francisco Syncope Rule risk factors by treating physicians.
• Structured telephone interviews at 14 days and blinded physician panel review to ascertain serious clinical events.

Main Results:

• The San Francisco Syncope Rule demonstrated a sensitivity of 89% and specificity of 42% for predicting any 7-day serious clinical event.
• For serious events not identified initially, sensitivity was 69% and specificity was 42%.
• These performance estimates were minimally impacted by missing follow-up data.

Conclusions:

• In this external validation cohort, the San Francisco Syncope Rule exhibited lower sensitivity and specificity compared to previous reports.
• The findings suggest a potential decline in the rule's effectiveness when applied to a new patient population.