How do you risk stratify syncope?

Risk Stratification of Syncope

Risk stratification of syncope should focus on identifying structural heart disease, abnormal ECG findings, and other high-risk features that predict increased morbidity and mortality.

Initial Risk Assessment

The evaluation of syncope requires systematic risk stratification to identify patients at high risk for adverse outcomes. The American College of Cardiology/American Heart Association guidelines recommend categorizing patients into high, intermediate, or low risk based on specific clinical features 1.

High-Risk Features

History and Demographics

• Age >60 years 1, 2
• Male sex 1
• Syncope during exertion 2
• Syncope while supine 1
• Absence of prodrome/warning signs 1
• Family history of sudden cardiac death 2
• Known structural heart disease or heart failure 1

Physical Examination

• Abnormal cardiac examination 2
• Systolic BP <90 mmHg 1, 2
• Slow recovery from syncope 1

ECG Findings

• Bifascicular block 1, 2
• QRS duration >120 ms 1
• Prolonged or short QT interval 2
• Ventricular pre-excitation 2
• Brugada pattern 2
• Evidence of arrhythmia 1
• Voltage criteria for left ventricular hypertrophy 1
• Ventricular pacing 1

Intermediate-Risk Features

• Recurrent syncope without high-risk features 1
• Age 45-60 years 1
• Comorbidities without immediate danger

Low-Risk Features

• Age <45 years 1
• No history of cardiovascular disease 1
• Normal ECG 1
• Clear vasovagal trigger 1
• Presence of prodromal symptoms (nausea/vomiting) 1

Validated Risk Stratification Tools

Several risk scores have been developed to assist with syncope risk stratification:

1. OESIL Score 1

   • Abnormal ECG
   • Age >65 years
   • No prodrome
   • History of cardiovascular disease

2. San Francisco Syncope Rule (SFSR) 1, 2

   • Abnormal ECG
   • Dyspnea
   • Hematocrit <30%
   • Systolic BP <90 mmHg
   • History of heart failure

3. Canadian Syncope Risk Score 3

   • Includes cardiac biomarkers
   • Predicts 30-day serious outcomes

Management Based on Risk Stratification

High-Risk Patients

• Immediate hospitalization 2
• Continuous cardiac monitoring 2
• Echocardiography if structural heart disease suspected 2
• Electrophysiological studies for suspected arrhythmic syncope 2

Intermediate-Risk Patients

• Referral to syncope specialist 1, 2
• Consider implantable loop recorder for recurrent unexplained syncope 2
• Tilt-table testing for suspected reflex syncope 2

Low-Risk Patients

• Outpatient management 2
• Education on trigger avoidance 2
• Physical counterpressure maneuvers for vasovagal syncope 2

Prognostic Implications

The presence of structural heart disease is the most important predictor of mortality in patients with syncope 1. Patients with syncope and advanced heart failure have a particularly high risk of sudden death (45% at 1 year) 1.

Long-term prognosis is related to:

• Effectiveness of therapy 1
• Severity and progression of underlying diseases 1
• Cardiac comorbidities 1

Common Pitfalls in Risk Stratification

• Underestimating risk in elderly patients 2
• Overreliance on diagnostic testing without clinical indication 2
• Failure to recognize cardiac syncope, which carries worse prognosis than reflex or orthostatic syncope 3
• Inadequate assessment of structural heart disease 1
• Dismissing single episodes of syncope without proper risk assessment 1

By following a systematic approach to risk stratification, clinicians can identify patients at high risk for adverse outcomes and ensure appropriate management to reduce morbidity and mortality associated with syncope.