What is included in a syncope workup?

Syncope Workup: Comprehensive Evaluation Protocol

A complete syncope workup must include detailed history, physical examination with orthostatic blood pressure measurements, and standard 12-lead ECG as the essential first-line evaluation, which establishes diagnosis in most patients without requiring extensive testing. 1

Initial Evaluation Components

Detailed History

• Event circumstances:

  • Position and activity when syncope occurred
  • Way of falling (slumping or kneeling over)
  • Presence of prodromal symptoms
  • Duration of loss of consciousness 2

• During the event (from eyewitness):

  • Skin color (pallor, cyanosis, flushing)
  • Breathing pattern (snoring)
  • Movements (tonic, clonic, tonic-clonic, minimal myoclonus, automatism)
  • Duration of movements
  • Onset of movement in relation to fall
  • Tongue biting 2

• Post-event symptoms:

  • Nausea, vomiting, sweating
  • Feeling of cold, confusion
  • Muscle aches, skin color
  • Injury, chest pain, palpitations
  • Urinary or fecal incontinence 2

• Background information:

  • Family history of sudden death or congenital arrhythmogenic heart disease
  • Previous cardiac disease
  • Neurological history (Parkinsonism, epilepsy, narcolepsy)
  • Metabolic disorders (diabetes)
  • Medication (antihypertensive, antianginal, antidepressant, antiarrhythmic, diuretics, QT-prolonging agents)
  • For recurrent syncope: time from first episode and number of spells 2, 1

Physical Examination

• Complete cardiovascular examination (murmurs, signs of heart failure)
• Orthostatic blood pressure measurements (lying and standing)
• Neurological examination
• Carotid sinus massage (in patients over 40 years with unexplained syncope) 1

Standard 12-lead ECG

• Look specifically for:
  • Bifascicular block
  • Other intraventricular conduction abnormalities (QRS duration >0.12s)
  • Mobitz I second-degree atrioventricular block
  • Asymptomatic sinus bradycardia (<50 beats/min) or sinoatrial block
  • Pre-excited QRS complexes
  • Prolonged QT interval
  • Brugada syndrome pattern
  • Signs of arrhythmogenic right ventricular dysplasia
  • Q waves suggesting myocardial infarction 2

Additional Testing Based on Initial Findings

Echocardiography

• Indicated when:
  • Initial evaluation suggests underlying heart disease
  • History, physical exam, and ECG don't provide diagnosis
  • Screening for valvular disease, hypertrophic cardiomyopathy, pulmonary embolism
  • Evaluating young athletes with unexplained syncope 2

Exercise Testing

• Indicated when:
  • Syncope occurred during or after exercise
  • Evaluating patients at risk for coronary artery disease
  • Monitoring blood pressure response to exercise (drop may indicate hypertrophic cardiomyopathy or autonomic failure)
  • Screening for catecholaminergic polymorphic ventricular tachycardia 2

ECG Monitoring

• Holter monitoring: For daily symptoms (24-48 hours)
• Event monitoring: For monthly symptoms (30-60 days)
• Implantable loop recorder: For infrequent symptoms or when other monitoring is inconclusive 2, 1

Specialized Testing

• Tilt table testing: For suspected neurally-mediated syncope
• Autonomic function testing: For suspected orthostatic hypotension
• Electrophysiological studies: For suspected arrhythmic causes
• Neuroimaging: Only when neurological event is suspected or head injury occurred 1, 3

Risk Stratification

After initial evaluation, patients should be classified as:

• High risk: Presence of structural heart disease, abnormal ECG, exertional syncope, or severe comorbidities (requires hospital admission)
• Low risk: Single episode with normal evaluation (can often be reassured with no further testing) 4

Common Pitfalls to Avoid

• Overuse of diagnostic tests without proper initial evaluation
• Misdiagnosis of seizures as syncope (look for post-ictal confusion and tongue biting)
• Failure to consider medication-induced syncope
• Premature cardiac pacing without adequate documentation of bradyarrhythmia
• Missing life-threatening causes of syncope (structural heart disease, arrhythmias) 1

Laboratory testing and neuroimaging have low diagnostic yield and should be ordered only when specifically indicated by history and physical examination findings 3, 4.