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Circulation. 2017;136:e60–e122. DOI: 10.1161/CIR.0000000000000499 August 1, 2017 e75 CLINICAL STATEMENTS AND GUIDELINES

Recommendations for Tilt-Table Testing

COR LOE Recommendations IIa B-R If the diagnosis is unclear after initial evaluation, tilt-table testing can be useful for patients with suspected V VS.208–213

See Online Data Supplement 15. Tilt-table testing has been used to evaluate patients with syncope for nearly 3 decades.208 It is an orthostatic stress test to assess the susceptibility of a vasovagal response to a postural change from a supine to an upright position. A positive response is defined as inducible presyncope or syncope associated with hypotension, with or without bradycardia (less commonly asystole). The hemodynamic response to the tilt maneuver determines whether there is a cardioinhibitory, vasodepressor, or mixed response.214 There is general consensus that a tilt-table angle of 70 degrees for 30 to 40 minutes would provide optimal yield.211,213,215 Adjunctive agents, such as a low dose of isoproterenol infusion or sublingual nitrates, may improve sensitivity but decrease specificity.210,212,216,217 A positive tilt-table test suggests a tendency or predisposition to V VS induced in the laboratory. This observation during tilt-table testing cannot necessarily define a causal etiology or be entirely conclusive of a reflex mechanism for syncope in the clinical setting. Correlation of tilt-table–induced findings to patients’ clinical presentation is critically important to prevent consequences of false-positive results from tilt-table testing.

The utility of tilt-table testing is highest in patients with a suspected V VS when syncope is recurrent. Several factors have reduced the role of tilt-table testing in the evaluation of syncope: the overall moderate sensitivity, specificity, and reproducibility of tilt-table testing; the presence of false-positive response in controls; the increasing recognition of V VS from a structured history taking; and the availability of long-term cardiac monitoring.24,211,213

IIa B-NR Tilt-table testing can be useful for patients with syncope and suspected delayed OH when initial evaluation is not diagnostic.218,219

See Online Data Supplement 15. OH with standing, or a similar fall in blood pressure within 3 minutes of upright tilt-table testing to 60 degrees,220 is distinct from delayed OH, characterized by a sustained decrease in blood pressure occurring beyond 3 minutes of standing or upright tilt-table testing.220,221 Delayed OH may be responsible for syncopal episodes or symptoms of orthostatic intolerance only after prolonged standing. In 1 retrospective study of 230 patients with OH, only 46% had OH within 3 minutes of head-up tilt; 15% had OH between 3 and 10 minutes; and 39% had OH only after 10 minutes of tilt-table testing.218 In 10-year follow-up data from 165 of these patients, 54% of individuals with delayed OH progressed to classic OH.219 The 10-year death rate in individuals with delayed OH was 29%, compared with 64% and 9% in individuals with baseline OH and controls, respectively.

IIa B-NR Tilt-table testing is reasonable to distinguish convulsive syncope from epilepsy in selected patients.222–225

See Online Data Supplement 15. Convulsive syncope is a term that can be used to describe any form of syncope manifesting with convulsive movements (eg, myoclonus). Prolonged convulsions and marked postictal confusion are uncommon in patients with syncope associated with convulsive movements,226 and fatigue is frequent after reflex syncope and may be confused with a postictal state.226 Tilt-table testing has been shown to be of value in this clinical setting when a detailed history cannot clearly determine whether the convulsive movements were secondary to syncope, given the need for objective evidence to help distinguish this entity from true epileptic seizures. In a prospective study of 15 patients with recurrent unexplained seizure-like episodes who were unresponsive to antiepileptic therapy,223 67% had convulsive movements associated with hypotension and bradycardia during tilt-table testing. In another study of 74 patients with a questionable diagnosis of epilepsy (because of drug-refractory seizures or clinically suspected not to be true epilepsy), a cardiac diagnosis was established in 42% of patients, with >25% developing profound hypotension or bradycardia during the head-up tilt-table test, confirming the diagnosis of V VS.225 Taken together, it can be estimated from these studies that approximately 50% of patients with either questionable or drug-refractory epilepsy have positive tilt-table tests suggestive of a vasovagal etiology.226

IIa B-NR Tilt-table testing is reasonable to establish a diagnosis of pseudosyncope.227–229

See Online Data Supplement 15. Psychogenic pseudosyncope should be suspected when patients present with frequent (even daily) symptoms that mimic V VS (and, in some cases, with a history of true V VS). It is often challenging to differentiate psychogenic syncope from true syncope. However, tilt-table testing may help to elucidate the diagnosis. During tilt-table testing, the apparent unconsciousness with loss of motor control, combined with normal blood pressure and heart rate (and a normal electroencephalogram [EEG] if such a recording is obtained), rules out true syncope and most forms of epilepsy.227–229 In 1 study of 800 patients who underwent tilttable testing, approximately 5% were diagnosed with pseudosyncope. Compared with patients with V VS, eye closure during the event, long periods of apparent transient loss of consciousness, and increased heart rate and blood pressure are highly specific for pseudosyncope. One study of 21 patients with suspected pseudosyncope who were subjected to tilt-table testing with continuous monitoring of the ECG, EEG, and blood pressure revealed 17 patients with non-epileptiform limb shaking without significant changes on an EEG or hemodynamic changes.227 III: No Benefit B-R Tilt-table testing is not recommended to predict a response to medical treatments for V VS.230,231

See Online Data Supplement 15. One of the purported advantages of tilt-table testing, in addition to suggesting a diagnosis of V VS, is the ability to assess the efficacy of pharmacological therapeutics in suppressing a vasovagal response to postural stress by evaluating the effectiveness of a therapy during repeated testing.230,231 Several small studies suggested a possible benefit, but these data were limited by the lack of reproducibility of tilt-table testing.232–235

3.2.6 Tilt-Table Testing: Recommendations

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