What is the tilt table test used for?

Tilt Table Testing: Clinical Applications and Indications

The tilt table test is primarily used to diagnose vasovagal syncope, orthostatic hypotension, and to distinguish syncope from epilepsy in patients with unexplained episodes of loss of consciousness. 1

Primary Indications for Tilt Table Testing

1. Suspected Vasovagal Syncope (VVS)

• Indicated when initial evaluation is inconclusive but VVS is suspected 1
• Serves as an orthostatic stress test to assess susceptibility to vasovagal response
• Particularly useful when:
  • Syncope remains unexplained after initial workup
  • Recurrent episodes occur without clear diagnosis
  • High-risk settings are involved (potential for injury or occupational implications)

2. Suspected Orthostatic Hypotension (OH)

• Especially valuable for detecting delayed orthostatic hypotension 1
• Can identify OH that occurs beyond 3 minutes of standing (delayed OH) 1
• Important prognostic value: delayed OH has 29% 10-year mortality rate compared to 9% in controls 1

3. Distinguishing Syncope from Epilepsy

• Helps differentiate convulsive syncope from epileptic seizures 1
• Particularly useful when:
  • Seizure-like activity accompanies loss of consciousness
  • Patients have drug-refractory "seizures"
  • Clinical suspicion exists that episodes are not true epilepsy

4. Diagnosing Pseudosyncope

• Can establish a diagnosis of psychogenic pseudosyncope 1
• Useful in patients with frequent episodes of transient loss of consciousness and suspected psychiatric problems 1

Test Methodology

The test involves:

• Positioning patient on a tilt table at 60-70° angle 1
• Monitoring for 30-40 minutes (passive phase) 1
• Optional use of provocative agents (isoproterenol or sublingual nitroglycerin) 1
• Continuous monitoring of blood pressure and heart rate 2

A positive response includes:

• Inducible presyncope or syncope
• Associated hypotension with or without bradycardia
• Responses classified as cardioinhibitory, vasodepressor, or mixed 1

Clinical Significance and Limitations

• Positive test suggests predisposition to VVS but cannot definitively establish causality 1
• Negative test does not exclude reflex syncope 1
• Correlation with patient's clinical presentation is critical 1
• Not recommended for assessing treatment efficacy 1

Important Caveats

• False positives can occur, especially with provocative agents 1
• Sensitivity ranges from 26-80%, specificity approximately 90% 1
• In patients with normal cardiac evaluation, the most likely diagnosis remains neurocardiogenic syncope even with a negative tilt test 1
• Contraindications for isoproterenol include ischemic heart disease, uncontrolled hypertension, and significant aortic stenosis 1

Special Populations

Pediatric Patients

• Useful for diagnosing VVS in children with unexplained syncope 1
• Can help identify children with convulsive syncope that mimics epilepsy 1
• Particularly valuable when combined with education on symptom awareness 1

Elderly Patients

• Can help distinguish syncope from falls in older adults 1
• Particularly important given higher morbidity and mortality of falls in this population

By providing controlled conditions to reproduce syncope, the tilt table test remains a valuable diagnostic tool in the evaluation of unexplained syncope, though its results must always be interpreted in the context of the patient's clinical presentation.