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Validation of the San Francisco Syncope Rule

February 4, 2017

Short Attention Span Summary

Playing CHESS with syncope
CHF, Hct < 30, EKG change, Shortness of breath, Systolic < 90 – this is the San Francisco Syncope Rule.  This was a prospective validation cohort of 791 patients.  It performed with 98% sensitivity and 56% specificity for detecting the 53 patients (6.7%) who developed pre-defined serious outcomes not apparent on initial ED evaluation.  It could have reduced admissions by 24%.

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The San Francisco Syncope Rule could have safely reduced almost one-quarter of admissions for syncope in this cohort.  However, later evidence has not found the same diagnostic accuracy.  The NNT has an excellent review of this clinical decision rule and found the risk of serious outcome at 7 days was 1 in 10, and the risk of death was 1 in 250.


Ann Emerg Med. 2006 May;47(5):448-54. Epub 2006 Jan 18.

Prospective validation of the San Francisco Syncope Rule to predict patients with serious outcomes.

Quinn J1, McDermott D, Stiell I, Kohn M, Wells G.

Author information:

1Division of Emergency Medicine, Stanford University, Palo Alto, CA 94304, USA. quinnj@stanford.edu

Comment in



We prospectively validate the San Francisco Syncope Rule (history of congestive heart failure, Hematocrit <30%, abnormal ECG result [new changes or non-sinus rhythm], complaint of shortness of breath, and systolic blood pressure <90 mm Hg during triage).


In a prospective cohort study, consecutive patients with syncope or near syncope presenting to an emergency department (ED) of a teaching hospital were identified and enrolled from July 15, 2002, to August 31, 2004. Patients with trauma, alcohol, or drug-associated loss of consciousness and definite seizures were excluded. Physicians prospectively applied the San Francisco Syncope Rule after their evaluation, and patients were followed up to determine whether they had had a predefined serious outcome within 30 days of their ED visit.


Seven hundred ninety-one consecutive visits were evaluated for syncope, representing 1.2% of all ED visits. The average age was 61 years, 54% of patients were women, and 59% of patients were admitted. Fifty-three visits (6.7%) resulted in patients having serious outcomes that were undeclared during their ED visit. The rule was 98% sensitive (95% confidence interval [CI] 89% to 100%) and 56% specific (95% CI 52% to 60%) to predict these events. In this cohort, the San Francisco Syncope Rule classified 52% of the patients as high risk, potentially decreasing overall admissions by 7%. If the rule had been applied only to the 453 patients admitted, it might have decreased admissions by 24%.


The San Francisco Syncope Rule performed with high sensitivity and specificity in this validation cohort and is a valuable tool to help risk stratify patients. It may help with physician decisionmaking and improve the use of hospital admission for syncope.

PMID: 16631985 [PubMed – indexed for MEDLINE]

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