This document provides information about the tilt table test procedure for evaluating syncope of unknown cause. It describes the indications, contraindications, preparation, phases of the procedure including pre-tilt, passive, and drug provocation. Interpretation of normal and abnormal responses is outlined. Caveats are discussed that the test has limited specificity and sensitivity and a positive result may not reflect the mechanism of spontaneous syncope. Complications are typically minor. Overall, the tilt table test is a commonly used procedure to help classify syncope and determine if reflex vasovagal mechanisms are involved.

1. TILT TABLE TEST
PHUNG HUY HOANG, MD MSc
Department of Cardiac Arrhythmias
115 People’s Hospital
March, 2020

2. SYNCOPE CLASSIFICATION
SYNCOPE
Reflex (neurally
mediated)
Vasovagal
Situational
Carotid sinus syndrome
Orthostatic
Hypotension
Drug-induced OH
Volume depletion
Primary autonomic failure
Secondary autonomic failure
Cardiac
Arrhythmias
Cardiac structural disease
Cardiopulmonary and great vessels
Brignole M., Moya A., de Lange F. J., et al. (2018), European Heart Journal, 39 (21), pp. 1883-1948

3. PATHOPHYSIOLOGY
• Healthy humans: orthostatic stress → peripheral pooling 500-1000ml of blood (lower
extremities and lower portion of the abdomen) =  25–50% intravascular volume →
triggering arterial mechanoreceptors (major role) + thoracic wall, cardiac
mechanoreceptors (minor role) → stimulate vasomotor center (VMC) via vagal
afferent C fibers.
• VMC → efferent vagal signals + neuroendocrine modulators → reflex
vasoconstriction of splanchnic, musculo-cutaneous, renal vascular beds →
maintaining systemic arterial blood pressure during standing.

4. Freeman R. (2018), Harrison's Principles of Internal Medicine, J. Larry Jameson, et al.,
Editors, McGraw Hill, pp. 122-129

5. Prasad S., Wazni O., Chung M., et al. (2007), Handbook of Cardiac Electrophysiology, Andrea Natale , Oussama Wazni, Editors, Informa Healthcare, pp. 147-164.

6. Rev Port Cardiol (Engl Ed) 2019 Sep;38(9):661-673

7. INDICATIONS
• Recurrent episodes of syncope of undetermined etiology
• Absence of structural heart disease
• Presence of structural heart disease + cardiac causes of syncope excluded.
• Unexplained single syncopal episode/high-risk settings (potential risk for physical
injury, occupational hazard)
• Discriminate suspected reflex vs orthostatic hypotension syncope
• Identify patients with documented bradyarrhythmia during reflex syncope to
determine whether a vasodepressor response is present
• Andrade J. G., Bennett M. T., Deyell M. W., et al. (2016), The Clinical Cardiacelectrophysiology Handbook, Cardiotext Publishing, pp. 347-354
• Benditt D. (2018), UpToDate.

8. INDICATIONS
Brignole M., Moya A., de Lange F. J., et al. (2018), European Heart Journal, 39 (21), pp. 1883-1948

9. CONTRA-INDICATIONS
• Hypotension/Isoproterenol may cause myocardial or cerebral ischemia
o Critical obstructive cardiac disease (critical proximal coronary artery stenosis,
critical valvular stenosis, or severe left ventricular outflow obstruction)
o Critical cerebrovascular stenosis
o Recent MI, strokes
• Pregnant women (hypotension → potentially harmful to fetus)
• Inability to cooperate
• Weight exceeds safe table operation
• Uncontrolled hypertension
• Abedin Z., Conner R. (2007), Essential Cardiac Electrophysiology With Self Assessment, Blackwell Publishing, pp. 218-228
• Benditt D. (2018), UpToDate
• Brignole M., Moya A., de Lange F. J., et al. (2018), European Heart Journal, 39 (21), pp. e43-e80

10. PATIENT PREPARATION + EQUIPMENT
• Fast at least 2-4h
• IV catheter prior to the procedure (administration of fluids and/or medications ie,
isoproterenol or nitroglycerin)
• Continuous ECG, beat-to-beat blood pressure monitoring
• Room free of distractions and overstimulation (avoid autonomic triggers)
• Motorized tilt-table:
• with a foot board and safety restraints
• capable of smoothly and rapidly moving the patient passively between supine
position & head-up 60-80o and quickly (< 10 seconds) → avoid the consequences
of prolonged hypotension
• Brignole M., Moya A., de Lange F. J., et al. (2018), European Heart Journal, 39 (21), pp. e43-e80
• Taylor S. G. (2015), Clinical Cardiac Electrophysiology in Clinical Practice, David T. Huang , Travis Prinzi, Editors, Springer, pp. 17-36
• Benditt D. (2018), UpToDate

11. Prasad S., Burkhardt D., Dresing T. (2007), Handbook of Cardiac Electrophysiology,
Andrea Natale , Oussama Wazni, Editors, Informa Healthcare, pp. 247-257

12. PROCEDURE
Pre-tilt
phase
Passive
phase
Drug
provocation
phase

13. PROCEDURE
Pre-tilt phase
Passive
phase
Drug
provocation
phase
• Monitored/supine position: obtain baseline HR, BP
• Ensure*:
• supine pre-tilt phase of ≥ 5min when there is no venous cannulation
• ≥ 20min when there is venous cannulation.
*Brignole M., Moya A., de Lange F. J., et al. (2018), European Heart Journal, 39 (21), pp. e43-e80
European Heart Journal (2018) 39, e43–e80

14. PROCEDURE
Pre-tilt phase
Passive
phase
Drug
provocation
phase
• Upright with NO isoproterenol or nitroglycerin infusion
• Tilt angle 60-70o
• Min = 20min, Max = 45min
• Increasing angle increases sensitivity but also reduces specificity*
*Andrade J. G., Bennett M. T., Deyell M. W., et al. (2016), The Clinical Cardiacelectrophysiology Handbook, Cardiotext Publishing, pp. 347-354

15. Pre-tilt phase
Passive
phase
Drug
provocation
phase
• If the patient has remained asymptomatic during the passive phase
• An additional 15 to 20 minutes
• Provocative agents:  diagnostic yield by 20–25%*
PROCEDURE
(*) Abedin Z., Conner R. (2007), Essential Cardiac Electrophysiology With Self Assessment, Blackwell Publishing, pp. 218-228.

16. Pre-tilt phase
Passive
phase
Drug
provocation
phase
• Either drug (isoproterenol or nitroglycerin) can be used ∈ local practice and clinician
expertise
• Isoproterenol: titrated 1-3 /minute →  HR by 20-25% above baseline (with or
without returning the patient to the supine position)
• Nitroglycerin: fixed dose of 300-400g of sublingual (in upright position)
• Diagnostic rates of NTG ≥ Isoproterenol; NTG = simpler to use and better tolerated(1),(2)
• Isoprosterenol: positive response,  specificity(3)
(1) Raviele A., Giada F., Brignole M., et al. (2000), Am J Cardiol, 85 (10), pp. 1194-8
(2) Delepine S., Prunier F., Leftheriotis G., et al. (2002), Am J Cardiol, 90 (5), pp. 488-91
(3) Prasad S., Wazni O., Chung M., et al. (2007), Handbook of Cardiac Electrophysiology, Andrea Natale , Oussama Wazni, Editors, Informa Healthcare, pp. 147-164
PROCEDURE

17. Arthur W., Kaye G. C. (2000), Postgraduate Medical Journal, 76 (902), pp. 750-753

18. END OFTEST
• End of protocol in absence of symptoms
• Syncope occur
• Progressive (>5 min) orthostatic hypotension
• Excessive tachycardia (> 220-age)
• Significant arrhythmias
• Hyperventilation leading to ETCO2<20 mmHg
• Patient distress
Taylor S. G. (2015), Clinical Cardiac Electrophysiology in Clinical Practice, David T. Huang , Travis Prinzi, Editors, Springer, pp. 17-36

19. TEST INTERPRETATION
Normal
BP: no change or slight  ≤ 10%, HR  ≤ 10% until patients are tilted back
again
Positive for reflex
syncope
Significant  in BP or HR + loss of consciousness or inability to maintain
posture
Suggestive of reflex
syncope
Significant  in BP or HR + symptoms suggestive of presyncope but without
loss of consciousness
Orthostatic
hypotension syncope
Progressive orthostatic hypotension (slow progressive decrease in systolic
blood pressure) with or without symptoms
Psychogenic
pseudosyncope
Lose consciousness or unable to maintain posture without significant  in BP
or HR
Postural tachycardia
syndrome (POTS)
Ssustained  HR ≥ 30 bpm or an increase ≥ 120 bpm within first 10 minutes
of the passive phase
False positive Hemodynamic changes occur in the absence of symptoms
The test must be interpreted in the context of the clinical scenario

20. Different Types of
Response to Tilt-
Testing
Modified VASIS classification
(Vasovagal Syncope International
Study)
Iana Simova , E-journal of Cardiology Practice, Vol. 13,
N° 35, 2015

21. ESC 2018
Normal tilt table test results
Tilt-induced reflex syncope
Classical orthostatic hypotension
Delayed orthostatic hypotension
Psychogenic pseudosyncope
Postural orthostatic tachycardiasyndrome

22. The core features of reflex syncope
differentiating it from OH are a
latency after head-up tilt, a ‘convex’
BP decrease, and a decrease in HR
The hallmarks of classical OH are no
BP latency after head-up tilt, a
(upwards) concave shape of the
decrease, and if HR changes, it
increases

24. Prasad S., Wazni O., Chung M., et al. (2007), Handbook of Cardiac Electrophysiology, Andrea Natale , Oussama Wazni, Editors, Informa Healthcare, pp. 147-164.

25. CAVEATS
• Limited specificity (60-80%), sensitivity (30-70%), and reproducibility (70%)
• False positive: up to 45% of those with no history of syncope
• Hemodynamic response to upright tilt testing may ≠ hemodynamic mechanism of
spontaneous syncopal episodes.
• Andrade J. G., Bennett M. T., Deyell M. W., et al. (2016), The Clinical Cardiacelectrophysiology Handbook, Cardiotext Publishing, pp. 347-354
• McLaughlin M. (2009), Practical Clinical Electrophysiology, Peter J. Zimetbaum , Mark E. Josephson, Editors, Wolters Kluer, pp. 179-192

26. COMPLICATIONS
• MINIMAL!
• NO reported deaths during test1
• Ranging from nausea/vomiting, headaches (NTG), palpitations (Isoprosterenol) to the
effects of a syncopal episode (quick return to supine position + raising legs = enough to
restore consciousness in most patients)
• Rarely ventricular arrhythmias (especially with isoproterenol provocation)2
• Self-limited atrial fibrillation2
1. Brignole M., Moya A., de Lange F. J., et al. (2018), European Heart Journal, 39 (21), pp. e43-e80
2. Prasad S., Wazni O., Chung M., et al. (2007), Handbook of Cardiac Electrophysiology, Andrea Natale , Oussama Wazni, Editors, Informa Healthcare, pp. 147-164

27. 1. Abedin Z., Conner R. (2007), "Syncope", Essential Cardiac Electrophysiology With Self Assessment, Blackwell Publishing, pp. 218-228.
2. Arthur W., Kaye G.C. (2000), "The pathophysiology of common causes of syncope", Postgraduate Medical Journal, 76 (902), pp. 750-753.
3. Brignole M., Moya A., de Lange F.J., et al. (2018), "Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of
syncope", European Heart Journal, 39 (21), pp. e43-e80.
4. Delepine S., Prunier F., Leftheriotis G., et al. (2002), "Comparison between isoproterenol and nitroglycerin sensitized head-upright tilt in patients
with unexplained syncope and negative or positive passive head-up tilt response", Am J Cardiol, 90 (5), pp. 488-91.
5. McLaughlin M. (2009), "Syncope", Practical Clinical Electrophysiology, Peter J. Zimetbaum , Mark E. Josephson, Editors, Wolters Kluer, pp. 179-
192.
6. Prasad S., Burkhardt D., Dresing T. (2007), "Head-up tilt (HUT) table testing", Handbook of Cardiac Electrophysiology, Andrea Natale ,
Oussama Wazni, Editors, Informa Healthcare, pp. 247-257.
7. Prasad S., Wazni O., Chung M., et al. (2007), "Syncope events, definitions, causes, and features", Handbook of Cardiac Electrophysiology,
Andrea Natale , Oussama Wazni, Editors, Informa Healthcare, pp. 147-164.
8. Raviele A., Giada F., Brignole M., et al. (2000), "Comparison of diagnostic accuracy of sublingual nitroglycerin test and low-dose isoproterenol
test in patients with unexplained syncope", Am J Cardiol, 85 (10), pp. 1194-8.
9. Taylor S.G. (2015), "Syncope, Tilt Testing, and Cardioversion", Clinical Cardiac Electrophysiology in Clinical Practice, David T. Huang , Travis
Prinzi, Editors, Springer, pp. 17-36.
10. Andrade J.G., Bennett M.T., Deyell M.W., et al. (2016), "Syncope", The Clinical Cardiacelectrophysiology Handbook, Cardiotext Publishing, pp.
347-354.
11. Benditt D. (2018), "Upright tilt table testing in the evaluation of syncope", UpToDate.
12. Brignole M., Moya A., de Lange F.J., et al. (2018), "2018 ESC Guidelines for the diagnosis and management of syncope", European Heart
Journal, 39 (21), pp. 1883-1948.
13. Freeman R. (2018), "Syncope", Harrison's Principles of Internal Medicine, J. Larry Jameson, et al., Editors, McGraw Hill, pp. 122-129.
REFERENCES

28. TILT TABLE TEST
PHUNG HUY HOANG, MD MSc
Department of Cardiac Arrhythmias
115 People’s Hospital
March, 2020