Risk Stratification Tools

The San Francisco Rule

The San Francisco Rule [3] identifies high-risk patients based on the presence of the following factors:

• History of congestive cardiac failure
• Haematocrit <30%
• Abnormal ECG
• Complaint of shortness of breath
• Systolic Blood Pressure <90 mm Hg

The presence of any factor is considered sufficient for the patient to be high risk.

If a patient score zero in the risk stratification tool, they are then said to be in the low risk group for serious outcome.

In the original validation study, the incidence of serious adverse events was 6.7% with the rule being 98% sensitive and 56% specific to predict adverse events.

NICE guidelines (5) also recommend that for patients presenting with transient loss of consciousness, refer anyone with the following for further assessment :

• An abnormal ECG
• TLOC during exercise
• Family history of sudden death (in a person <40 years old or an inherited cardiac condition)
• New or unexplained breathlessness
• Heart murmur