Table 2.

High-risk and low-risk criteria for syncope at initial evaluation (Adapted from 2018 ESC Guidelines for the diagnosis and management of syncope⁸²)

Syncopal events
Low-risk
Associated with prodrome typical or reflex syncope (e.g. light-headedness, feeling of warmth, sweating, nausea, vomiting)
After sudden unexpected unpleasant sight, sound, smell, or paina
After prolonged standing or crowded, hot places
During a meal or postprandial
Triggered by cough, defaecation, or micturition
With head rotation or pressure on carotid sinus (e.g. tumour, shaving, tight collars)
Standing from supine/sitting position
High-risk
Major
New onset of chest discomfort, breathlessness, abdominal pain, or headache
Syncope during exertion or when supine
Sudden onset palpitation immediately followed by syncope
Presence of structural heart disease especially left ventricular dysfunction and/or history of myocardial infarction
Minor (high-risk only if associated with structural heart disease or abnormal ECG):
No warning symptoms or short (<10 s) prodrome
Family history of sudden cardiac death at young age
Syncope in the sitting position

^aSudden loud sounds (as an alarm clock) may trigger VF in some long QT syndrome patients.

ECG, electrocardiogram; VF, ventricular fibrillation.