evaluation of selected patients with syncope. The role for tilt table testing is limited since the initial diagnostic evaluation (without tilt testing) is often diagnostic in patients with vasovagal syncope, and tilt table testing has limited reproducibility and diagnostic accuracy. (See 'Test performance' above.) However, a positive test that reproduces patient symptoms may not only be helpful diagnostically but may also increase patient confidence that an accurate diagnosis has been made. https://www.uptodate.com/contents/upright-tilt-table-testing-in-the-evaluation-of-syncope/print 12/22 7/6/23, 2:38 PM Upright tilt table testing in the evaluation of syncope - UpToDate With the understanding that tilt table testing is an imperfect diagnostic test requiring experienced interpretation and that clinical practice varies, tilt table testing may be included as part of the complete syncope evaluation for selected patients in the following settings: Syncope of unknown cause For recurrent syncope (or a single episode with high risk of physical injury should syncope recur) with unknown cause after initial evaluation. If structural heart disease is present, cardiac causes of syncope should be excluded before tilt table testing is performed. Suspected vasovagal or orthostatic syncope To help confirm the diagnosis if the diagnosis is uncertain after the initial evaluation and to identify the mechanism of syncope (eg, cardioinhibitory and/or vasodepressor) in selected patients with suspected vasovagal or orthostatic syncope, which influences therapy. (See "Reflex syncope in adults and adolescents: Clinical presentation and diagnostic evaluation", section on 'Upright tilt table test' and "Mechanisms, causes, and evaluation of orthostatic hypotension", section on 'Diagnostic evaluation' and "Reflex syncope in adults and adolescents: Treatment" and "Reflex syncope in adults and adolescents: Treatment", section on 'Additional measures'.) Evaluation of autonomic system function Tilt table testing may be a component of evaluation of the autonomic system. (See "Diabetic autonomic neuropathy" and "Hereditary sensory and autonomic neuropathies" and "Mechanisms, causes, and evaluation of orthostatic hypotension" and "Immune-mediated neuropathies".) Contraindications Tilt table testing should not be performed in patients who have severe coronary or cerebrovascular disease or are pregnant. (See 'Contraindications' above.) Equipment and procedure Upright tilt table testing is typically performed in an electrophysiology laboratory or dedicated procedure room using a special motorized tilt table that raises to 60 to 70 degrees with rapid return to a horizontal position. The passive (drug-free) phase is 20 to 45 minutes long. If the initial passive phase is negative, a drug provocation phase using isoproterenol or nitroglycerin may be performed. (See 'Tilt table testing procedure' above.) Interpretation The tilt table test findings should be interpreted in the context of all relevant clinical data, particularly information about the patient s spontaneous events and other potential causes of events (eg, structural heart disease). Although the tilt table test is frequently positive in patients with vasovagal syncope, it is not the gold standard for the diagnosis of vasovagal syncope, as it has limited sensitivity, specificity, and reproducibility. https://www.uptodate.com/contents/upright-tilt-table-testing-in-the-evaluation-of-syncope/print 13/22 7/6/23, 2:38 PM Upright tilt table testing in the evaluation of syncope - UpToDate (See 'Test interpretation' above and 'Test performance' above and "Reflex syncope in adults and adolescents: Clinical presentation and diagnostic evaluation", section on 'Diagnosis'.) Symptomatic response without syncope (see 'Patterns without syncope' above): Postural tachycardia syndrome (POTS) Key features include symptoms of orthostatic intolerance (lightheadedness, palpitations, fading vision, presyncope, difficulty concentrating, or headache) with a sustained increase in heart rate (HR) 30 beats per minute (bpm; 40 bpm for individuals <20 years old) within 10 minutes after the start of head-up tilt with no decline in blood pressure (BP). However, other factors such as dehydration should be excluded before tilt table testing. (See "Postural tachycardia syndrome", section on 'Diagnostic approach'.) Possible vasovagal response If a patient experiences symptoms suggestive of presyncope without loss of consciousness (LOC) with a significant fall in BP ( 40 mmHg decline in systolic BP) or HR ( 60 bpm decline in HR), the patient is returned to the baseline position, and the test is considered suggestive of vasovagal syncope. (See "Reflex syncope in adults and adolescents: Clinical presentation and diagnostic evaluation", section on 'Upright tilt table test'.) Nonspecific response After a variable period of time after head-up tilt there is commonly a mild decrease in BP (generally <10 mm Hg decline in systolic BP) and mild increase in HR (by 10 percent). The patient may or may not experience dizziness during this nondiagnostic response. Patterns with apparent syncope (see 'Patterns with syncope or apparent syncope' above): Vasovagal response Key characteristics of the vasovagal response are an initial sinus tachycardia with onset of upright posture followed by a delayed accelerating fall in BP with mild to severe fall in HR ( figure 1). Orthostatic hypotension Key features of orthostatic hypotension (OH) are one or both of the following: an immediate fall in BP with or without an increase in HR [11] or a delayed hypotensive response at three to five minutes after onset of upright posture. Pseudosyncope During head-up tilt, if the patient appears to lose consciousness or is unable to maintain posture without a significant fall in BP or HR, the test is considered positive for psychogenic pseudosyncope. (See "Psychogenic nonepileptic seizures: Etiology, clinical features, and diagnosis".) https://www.uptodate.com/contents/upright-tilt-table-testing-in-the-evaluation-of-syncope/print 14/22 7/6/23, 2:38 PM Upright tilt table testing in the evaluation of syncope - UpToDate Test performance The sensitivity and specificity of tilt table testing are uncertain given the lack of a clinical gold standard. Reported sensitivity rates for passive phase testing have ranged from 13 to 75 percent and specificity may be greater than 90 percent. Drug provocation yields higher sensitivity but at the expense of a lower specificity. Complications Tilt table testing is rarely complicated by prolonged asystole or hypotension. Atrial fibrillation is infrequently induced. Ventricular fibrillation is a rare complication of isoproterenol administration in patients with heart disease. (See 'Complications and side effects' above.) ACKNOWLEDGMENT The UpToDate editorial staff acknowledges Brian Olshansky, MD, who contributed to earlier versions of this topic review. Use of UpToDate is subject to the Terms of Use. REFERENCES 1. Sutton R, Fedorowski A, Olshansky B, et al. Tilt testing remains a valuable asset. Eur Heart J 2021; 42:1654. 2. Shen WK, Sheldon RS, Benditt DG, et al. 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines, and the Heart Rhythm Society. J Am Coll Cardiol 2017. 3. Sheldon RS, Grubb BP 2nd, Olshansky B, et al. 2015 heart rhythm society expert consensus statement on the diagnosis and treatment of postural tachycardia syndrome, inappropriate sinus tachycardia, and vasovagal syncope. Heart Rhythm 2015; 12:e41. 4. Brignole M, Moya A, de Lange FJ, et al. 2018 ESC Guidelines for the diagnosis and management of syncope. Eur Heart J 2018; 39:1883. 5. Adkisson WO, Benditt DG. Head-up tilt table testing. In: Cardiac Electrophysiciology: from Ce ll to Bedside, 7th ed, Zipes DP, Jalife J, Stevenson WG (Eds), Elsevier Saunders, Philadelphia 2 017. p.630. 6. Thijs RD, Brignole M, Falup-Pecurariu C, et al. Recommendations for tilt table testing and other provocative cardiovascular autonomic tests in conditions that may cause transient loss of consciousness : Consensus statement of the European Federation of Autonomic https://www.uptodate.com/contents/upright-tilt-table-testing-in-the-evaluation-of-syncope/print 15/22 7/6/23, 2:38 PM Upright tilt table testing in the evaluation of syncope - UpToDate Societies (EFAS) endorsed by the American Autonomic Society (AAS) and the European Academy of Neurology (EAN). Clin Auton Res 2021; 31:369. 7. Brignole M, Russo V, Arabia F, et al. Cardiac pacing in severe recurrent reflex syncope and tilt-induced asystole. Eur Heart J 2021; 42:508. 8. Kochiadakis GE, Papadimitriou EA, Marketou ME, et al. Autonomic nervous system changes in vasovagal syncope: is there any difference between young and older patients? Pacing Clin Electrophysiol 2004; 27:1371. 9. Sheldon R, Rose S, Koshman ML. Isoproterenol tilt-table testing in patients with syncope and structural heart disease. Am J Cardiol 1996; 78:700. 10. Leman RB, Clarke E, Gillette P. Significant complications can occur with ischemic heart disease and tilt table testing. Pacing Clin Electrophysiol 1999; 22:675. 11. Brignole M, Moya A, de Lange FJ, et al. Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope. Eur Heart J 2018; 39:e43. 12. Claffey P, P rez-Denia L, Rivasi G, et al. Near-infrared spectroscopy in evaluating psychogenic pseudosyncope-a novel diagnostic approach. QJM 2020; 113:239. 13. Mallat Z, Vicaut E, Sangar A, et al. Prediction of head-up tilt test result by analysis of early heart rate variations. Circulation 1997; 96:581. 14. Shen WK, Jahangir A, Beinborn D, et al. Utility of a single-stage isoproterenol tilt table test in adults: a randomized comparison with passive head-up tilt. J Am Coll Cardiol 1999; 33:985. 15. Aerts AJ, Dendale P, Daniels C, et al. Intravenous nitrates for pharmacological stimulation during head-up tilt testing in patients with suspected vasovagal syncope and healthy controls. Pacing Clin Electrophysiol 1999; 22:1593. 16. Gisolf J, Westerhof BE, van Dijk N, et al. Sublingual nitroglycerin used in routine tilt testing provokes a cardiac output-mediated vasovagal response. J Am Coll Cardiol 2004; 44:588. 17. Parry SW, Gray JC, Newton JL, et al. 'Front-loaded' head-up tilt table testing: validation of a rapid first line nitrate-provoked tilt protocol for the diagnosis of vasovagal syncope. Age Ageing 2008; 37:411. 18. Raviele A, Giada F, Brignole M, et al. Comparison of diagnostic accuracy of sublingual nitroglycerin test and low-dose isoproterenol test in patients with unexplained syncope. Am J Cardiol 2000; 85:1194. 19. Del pine S, Prunier F, Lefth riotis G, et al. 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 2002; 90:488. https://www.uptodate.com/contents/upright-tilt-table-testing-in-the-evaluation-of-syncope/print 16/22 7/6/23, 2:38 PM Upright tilt table testing in the evaluation of syncope - UpToDate 20. van Dijk JG, van Rossum IA, van Houwelingen M, et al. Influence of Age on Magnitude and Timing of Vasodepression and Cardioinhibition in Tilt-Induced Vasovagal Syncope. JACC Clin Electrophysiol 2022; 8:997. 21. Moya A, Brignole M, Menozzi C, et al. Mechanism of syncope in patients with isolated syncope and in patients with tilt-positive syncope. Circulation 2001; 104:1261. 22. Brignole M, Menozzi C, Del Rosso A, et al. New classification of haemodynamics of vasovagal syncope: beyond the VASIS classification. Analysis of the pre-syncopal phase of the tilt test without and with nitroglycerin challenge. Vasovagal Syncope International Study. Europace 2000; 2:66. 23. Kurbaan AS, Bowker TJ, Wijesekera N, et al. Age and hemodynamic responses to tilt testing in those with syncope of unknown origin. J Am Coll Cardiol 2003; 41:1004. 24. Macedo P, Leite LR, Asirvatham SJ, et al. Head Up Tilt Testing: An Appraisal of Its Current Role in the Management of Patients with Syncope. J Atr Fibrillation 2011; 4:333. 25. Brignole M, Gianfranchi L, Menozzi C, et al. Role of autonomic reflexes in syncope associated with paroxysmal atrial fibrillation. J Am Coll Cardiol 1993; 22:1123. 26. Petersen ME, Williams TR, Gordon C, et al. The normal response to prolonged passive head up tilt testing. Heart 2000; 84:509. 27. Ungar A, Sgobino P, Russo V, et al. Diagnosis of neurally mediated syncope at initial evaluation and with tilt table testing compared with that revealed by prolonged ECG monitoring. An analysis from the Third International Study on Syncope of Uncertain Etiology (ISSUE-3). Heart 2013; 99:1825. 28. Kapoor WN, Brant N. Evaluation of syncope by upright tilt testing with isoproterenol. A nonspecific test. Ann Intern Med 1992; 116:358. 29. Kim JH, Lee SH, Park SJ, et al. Atrial fibrillation occurring during head-up tilt testing: Once detected, atrial fibrillation should be monitored, regardless of how it is detected. Heart Rhythm 2019; 16:520. 30. Shenthar J, Pujar D, Aravind Prabhu M, Sadashivappa Surhynne P. Ventricular fibrillation a rare complication during head-up tilt test. HeartRhythm Case Rep 2015; 1:363. Topic 1016 Version 29.0 https://www.uptodate.com/contents/upright-tilt-table-testing-in-the-evaluation-of-syncope/print 17/22 7/6/23, 2:38 PM Upright tilt table testing in the evaluation of syncope - UpToDate GRAPHICS Algorithm for syncope/collapse This algorithm poses key questions about a collapse episode, including whether and when LOC occurred. However, in the absence of a credible witness, information about such episodes is often limited, as the affected individual may not have accurate recall of the event. Some causes have more than one possible type of presentation. LOC: loss of consciousness; BLS: basic life support; ACLS: advanced cardiac life support; SAH: subarachnoid hemorrhage; TIA: transient ischemic attack. This includes actual LOC as well as apparent LOC. Accidental falls without LOC often have multiple causes, including gait, posture, or balance impairment, environmental hazard, vertigo, focal seizure, TIA, stroke, and presyncope. https://www.uptodate.com/contents/upright-tilt-table-testing-in-the-evaluation-of-syncope/print 18/22 7/6/23, 2:38 PM Upright tilt table testing in the evaluation of syncope - UpToDate These conditions result in apparent transient LOC, although consciousness may be preserved. Other causes of collapse may cause secondary head trauma. Most TIAs and strokes are not associated with LOC. An SAH may cause transient or prolonged LOC. A rare cause of LOC is a brainstem stroke. Graphic 131146 Version 1.0 https://www.uptodate.com/contents/upright-tilt-table-testing-in-the-evaluation-of-syncope/print 19/22 7/6/23, 2:38 PM Upright tilt table testing in the evaluation of syncope - UpToDate Heart rate and blood pressure patterns observed in head-up tilt table testing Shown are the heart rate and blood pressure responses seen during tilt table testing in patients with various etiologies of syncope including classic neurocardiogenic syncope, pure autonomic failure, or POTS. HR: heart rate; BP: blood pressure; POTS: postural orthostatic tachycardia syndrome. Reproduced with permission from: Grubb BP. Neurocardiogenic syncope. In: Syncope: Mechanisms and Management, Grubb BP, Olshansky B (Eds), Furtura https://www.uptodate.com/contents/upright-tilt-table-testing-in-the-evaluation-of-syncope/print 20/22 7/6/23, 2:38 PM Upright tilt table testing in the evaluation of syncope - UpToDate Publishing Co., Armonk, NY, 1997. p. 73-166. Copyright 1997 Futura Publishing Co. Graphic 55504 Version 4.0 https://www.uptodate.com/contents/upright-tilt-table-testing-in-the-evaluation-of-syncope/print 21/22 7/6/23, 2:38 PM Upright tilt table testing in the evaluation of syncope - UpToDate Contributor Disclosures David Benditt, MD Equity Ownership/Stock Options: Medtronic [Pacemakers/event recorders and defibrillators]. Grant/Research/Clinical Trial Support: Medtronic [Pacemakers/event recorders and defibrillators]; St Jude Medical [Pacemakers/event recorders and defibrillators]. Consultant/Advisory Boards: Medtronic [Pacemakers/event recorders and defibrillators]; Zoll [Pacemakers/event recorders and defibrillators]. Other Financial Interest: Advanced CPR Solutions [Outside director]. All of the relevant financial relationships listed have been mitigated. Peter Kowey, MD, FACC, FAHA, FHRS Equity Ownership/Stock Options: VuMedi [Arrhythmias]. Consultant/Advisory Boards: Abbvie [Arrhythmias]; Acesion Pharma [Arrhythmias]; Allergan [Arrhythmias, cardiac safety of non-cardiac drugs]; Anthos [Anticoagulants]; Boehringer-Ingelheim [Arrhythmias]; Bristol-Meyers-Squibb [Arrhythmias]; Daiichi Sankyo [Arrhythmias]; Gilead [Arrhythmias]; Huya [Arrhythmias]; InCarda Therapeutics [Arrhythmias]; INSTA [Arrhythmias]; Johnson & Johnson [Arrhythmias]; Medtronic [Arrhythmias]; Milestone [Arrhythmias]; Novartis [Arrhythmias, cardiac safety of non-cardiac drugs]; Pfizer [Arrhythmias]; Sanofi [Arrhythmias]; Takeda [Arrhythmias]. All of the relevant financial relationships listed have been mitigated. Susan B Yeon, MD, JD, FACC No relevant financial relationship(s) with ineligible companies to disclose. Contributor disclosures are reviewed for conflicts of interest by the editorial group. When found, these are addressed by vetting through a multi-level review process, and through requirements for references to be provided to support the content. Appropriately referenced content is required of all authors and must conform to UpToDate standards of evidence. Conflict of interest policy https://www.uptodate.com/contents/upright-tilt-table-testing-in-the-evaluation-of-syncope/print 22/22