International Validation of the Canadian Syncope Risk Score

Quick Takes

  • The Canadian Syncope Risk Score (CSRS) uses nine clinical, electrocardiographic, and lab components to predict serious clinical outcomes after complete emergency department (ED) evaluation for syncope.
  • This study compared how well the CSRS performed compared to another validated syncope score, the OESIL score.
  • While the CSRS performed better than the OESIL score, the most interesting study finding is that the CSRS’s superior performance was matched by one component of the nine-component score, clinician classification of syncope (vasovagal vs. cardiac vs. other) at ED discharge.

Study Questions:

How does the Canadian Syncope Risk Score (CSRS) perform in predicting serious clinical plus procedural events at 30 days when compared to the Osservatorio Epidemiologico della Sincope nel Lazio (OESIL) score?


This was a prospective observational study of patients ≥40 years old presenting to the emergency department (ED) with syncope within the prior 12 hours. All subjects had an electrocardiogram (ECG); the remainder of the workup in the ED was left to the discretion of the treating physician. After complete ED evaluation, the presenting syncope was classified as vasovagal, cardiac, or other by the treating physician. The CSRS includes nine components (yes/no): predisposition to vasovagal syncope (reassuring factor), history of heart disease, systolic blood pressure <90 or >180 mm Hg, elevated troponin, abnormal QRS axis, QRS duration >130 ms, corrected QT interval >480 ms, vasovagal syncope (reassuring factor), and cardiac syncope. Primary outcomes included: 1) a composite of serious clinical outcomes (death, life-threatening arrhythmia, myocardial infarction, pulmonary embolism, aortic dissection, etc.), and procedural interventions for the treatment of syncope at 30 days; and 2) a clinical-only outcome that did not include procedural interventions.


A total of 2,283 subjects were included in the analysis; 1,235 (54%) patients were hospitalized. The primary clinical plus procedural outcome at 30 days occurred in 165 (7.2%), and the clinical-only outcome occurred in 70 (3.1%) patients. The CSRS performed better than the OESIL score at predicting both the composite outcome and the clinical-only outcome. Only 9 of 1,388 (0.6%) patients identified as very low or low risk by the CSRS had adverse clinical-only outcomes at 30 days, whereas 14 of 75 (18.7%) of those who were very high risk did. A simplified model of the CSRS using only the clinician classification of syncope (vasovagal vs. cardiac vs. other) at ED discharge performed as well as the larger CSRS model (area under the receiver-operating characteristic curve [AUC], 0.76; 95% confidence interval [CI], 0.71-0.81 compared to AUC, 0.80; 95% CI, 0.75-0.84 for the larger model) in predicting the 30-day clinical-only outcome.


In this study, the CSRS outperformed the OESIL score in predicting serious outcomes after complete ED evaluation for syncope in patients ≥40 years old. Although not an objective measure, physician classification of syncope at ED discharge (vasovagal vs. cardiac vs. other) was as effective as the CSRS and more effective than the OESIL in predicting 30-day serious outcomes after syncope.


Use of the larger nine-component CSRS is likely superfluous given that one component, provider classification of syncope as vasovagal versus cardiac versus other, performed as well as the CSRS in predicting serious clinical outcomes at 30 days. Enthusiasm for multi-component syncope prediction scores will likely cool based on the results of this study.

Clinical Topics: Arrhythmias and Clinical EP, Prevention, Vascular Medicine, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias

Keywords: Aneurysm, Dissecting, Arrhythmias, Cardiac, Blood Pressure, Electrocardiography, Emergency Service, Hospital, Myocardial Infarction, Patient Discharge, Primary Prevention, Pulmonary Embolism, Risk Factors, Syncope, Syncope, Vasovagal, Troponin

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