Syncope

• Transient loss of consciousness caused by a period of inadequate cerebral blood flow
• Variety of causes: vasovagal (reflex syncope), neurological, cardiac, intoxication or metabolic causes, psychiatric causes
• Cardiac syncope often has limited prodromal symptoms (prodromes or warning signs are common in reflex syncope)

Investigation

• ECG
• Echocardiography if suspecting structural heart disease

Cardiac Causes of Syncope

• Coronary artery disease
• Structural heart disease
• Sinus bradycardia
• Third-degree AV block or second-degree AV block (Mobitz II)
• Pre-excitation (Wolff-Parkinson-White Syndrome)
• Ventricular tachycardia
• Supraventricular tachycardia with fast ventricular rate
• Non-sustained polymorphic VT
• Brugada syndrome
• Arrhythmogenic ventricular cardiomyopathy
• Pacemaker or ICD malfunction

Reference: UpToDate - Syncope