What is a tilt table test?

What is a Tilt Table Test?

A tilt table test is a diagnostic procedure that tilts a patient upright (typically 60-70 degrees) for 20-45 minutes while monitoring blood pressure and heart rate to provoke and diagnose vasovagal (neurocardiogenic) syncope and orthostatic hypotension. 1

How the Test Works

The test attempts to reproduce a syncopal episode in a controlled medical setting by challenging the body's ability to maintain blood pressure during positional changes. 1

Key procedural elements include:

• Patient positioning: The patient is secured to a motorized table that tilts to 60-70 degrees from horizontal 1
• Monitoring: Continuous beat-to-beat blood pressure and heart rate (ECG) are recorded throughout the test 2
• Duration: A supine pre-tilt phase of at least 5-20 minutes (depending on whether IV access is needed), followed by an upright passive phase of 20-45 minutes 1
• Pharmacologic provocation (optional): Sublingual nitroglycerin (300-400 mcg) or isoproterenol infusion may be added after the passive phase to increase sensitivity, though this reduces specificity 1

What the Test Reveals

The endpoint is induction of syncope or presyncope accompanied by:

• Reflex hypotension/bradycardia (vasovagal syncope) 1
• Delayed orthostatic hypotension 1

The response pattern helps classify the mechanism as cardioinhibitory (primarily bradycardia/asystole), vasodepressor (primarily hypotension), or mixed. 1

Clinical Indications

According to the European Society of Cardiology, tilt table testing is indicated to confirm suspected reflex syncope when the diagnosis is not established by initial clinical evaluation. 1

Specific situations where testing is valuable:

• Unexplained single syncopal episode in high-risk settings (risk of injury, occupational implications like pilots) 1
• Recurrent syncope after cardiac causes have been excluded 1
• Distinguishing syncope from epilepsy when jerking movements are present 1
• Differentiating syncope from falls in elderly patients 1
• Investigating suspected psychiatric causes of transient loss of consciousness 1

Testing is NOT usually needed when reflex syncope is already clearly diagnosed by clinical history alone, or for single/rare episodes without high-risk features. 1

Test Performance Characteristics

The American Heart Association and American College of Cardiology report that sensitivity ranges from 26-80% depending on protocol, while specificity is approximately 90-94%. 1

Critical limitation: A negative tilt table test does not exclude reflex syncope—the most likely diagnosis remains neurocardiogenic syncope even with a negative test in patients with otherwise normal cardiac evaluation. 1

The false positivity rate is approximately 6-8% in healthy controls, and increases with use of provocative agents. 3

Safety Profile

Tilt table testing is very safe with no reported deaths. 1

Rare complications include:

• Life-threatening ventricular arrhythmias with isoproterenol in patients with ischemic heart disease or sick sinus syndrome 1
• Self-limited atrial fibrillation 1
• Common minor side effects: palpitations (isoproterenol), headache (nitroglycerin) 1

Contraindications to isoproterenol include: ischemic heart disease, uncontrolled hypertension, left ventricular outflow obstruction, and significant aortic stenosis. 1

Resuscitation equipment should be available despite the low risk. 1

Important Clinical Caveats

The test has no value in assessing treatment efficacy due to poor day-to-day reproducibility. 1

However, tilt testing is useful to demonstrate susceptibility to reflex syncope and thereby educate patients about recognizing prodromal symptoms and initiating physical counterpressure maneuvers (leg crossing, hand gripping, arm tensing) to prevent syncope. 1

A positive cardioinhibitory response predicts asystolic spontaneous syncope with high probability, but vasodepressor or mixed responses—or even negative tests—do not exclude asystole during spontaneous episodes. 1