About 1 to 2% of ER visits deal with Syncope. Most of these are vaso-vagal episodes that do not require more work up. But,  beside the obvious slam dunk: you passed out because you have a giant PE or your Accucheck reads 2, there is a middle ground of patients that have no obvious etiology but you just feel cringy about sending home. This study was to help you decide what to do about those people.

Study Question:

Does the San Francisco Syncope Criteria help distinguish who is high risk for an adverse event in the next 30 days?

Design :

This was a prospective cohort study. To summarize it, 791 consecutive syncopized patients were seen in the ED and enrolled in the study. The physicians treated them as they would, but then marked a form with the San Francisco rule and these patients were followed up on for serious outcomes in the next 30 days. They were able to complete the form on 767 patients and able to follow up on 752. The average age of the patients was 61 with a standard deviation of 22 years. This means that 95% of the patients were between the ages of 17 and 105… assuming a standard bell curve. That’s a pretty inclusive set of human subjects.

Talking about inclusion, they included- for their definition of serious outcome- any condition that could cause or could likely cause a return ED visit, anything that received a procedural intervention, MIs, death, PEs, hemorrhages, etc.


They found that 13.7% of patients had serious outcomes within 30 days, half of which were diagnosed during the initial ED visit. This leaves 53 patients who left the ED without a diagnosis, who had a serious outcome in the next 30 days. All but one of these patient’s were found to be high risk for serious outcomes using the San Francisco rule. This gives the rule a 98% sensitivity. The rule was also found to overall have a specificity of 56%. Which though is not the highest specificity, they found that 7% of the admissions would have been avoided if the San Francisco rule was used.  


As in any study, there are limitations to the findings. For instance, though there was a wide age range, I would not include pediatric patient’s in this rule. This was a single site study, and 5% of patients were lost to follow up. Though taken in stride in the article, I think the largest limitation to the study is that it did not go specifically into sens or spec of specific outcomes (i.e. MI, PE, etc.) and therefore is unable to give suggestions for work up while inpatient if the patient is high risk nor suggestions for outpatient follow up.

Because of this, I think this criteria becomes more of a tool to help hone your gestalt than to base your decisions off of. Which is exactly how the authors sell their work; offering the advice to use it to supplement decision making and admissions.

I think it is important to note though, that as of yet there are not any better criteria for these syncope decisions. A recent paper in 2017 ( a 232 page novel of an article) offered it’s own admission criteria… that is very similar to the San Francisco rule. (Shen et al.)

Take Away:

Use the San Francisco Rule (CHESS mnemonic) to help guide your decision for admission v. discharge on the middle ground syncope patient. 


Quinn, J. McDermott, D. Stiell, I. Kohn, M. Wells, G. Prodpective Validation of the San Francisco Syncope Rule to Predict Patients With Serious Outcomes. Annals of Emergency Medicine. 2006 May; 47(5):448-54.

Shen, W. Sheldon, R. Benditt, D. Cohen, M. Forman, D. Goldberger, Z. Grubb, B. Hamden, M. Krahn, A. Link, M. Ofshanksy, B. Rai, S. Sandhu, R. Soralia, D. Sun, B. YAncy, C. 2017 ACC/AHA/HRS Guideline for the evaluation and management of patients with Syncope: A report of the American College of Cardiology/ American Heart Association Task Force on Clinical Practice Guideline and the Heart Rhythm Society. Circulation. 2017 Aug; 136 (5):60-e122

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