Tilt Testing Remains a Valuable Asset

Richard Sutton; Artur Fedorowski; Brian Olshansky; J. Gert van Dijk; Haruhiko Abe; Michele Brignole; Frederik de Lange; Rose Anne Kenny; Phang Boon Lim; Angel Moya; Stuart D. Rosen; Vincenzo Russo; Julian M. Stewart; Roland D. Thijs; David G. Benditt

Disclosures

Eur Heart J. 2021;42(17):1654-1660. 

In This Article

Tilt-test Methodology

Detailed discussion of TT protocols is provided in several practice guidelines and consensus reports.[8,10,11] Failure to follow protocols, especially for induction of syncope, will lead to misinterpretation. In addition, the European Heart Rhythm Association has recommended staffing requirements for performing tilt-table testing including use of highly trained personnel other than physicians.[28]

The 2018 ESC syncope guidelines[10] give tilt-table testing a IIb indication (level of evidence C) to discriminate convulsive syncope from epilepsy. Misdiagnosis of epilepsy as syncope is a more frequently recognized problem and tilt-table testing has been shown to be helpful in this regard.[29] The addition of EEG monitoring to assist in making this distinction has proved particularly valuable and may readily be added to TT.[30,31]

Increasingly, laboratories that undertake TT are encouraged to include active stand testing in assessing patients.[9,10] However, active standing should not be confused with TT. While both introduce orthostatic stress, there are important physiological differences. Active standing, unlike passive head-up tilt, invokes the skeletal muscle pump. The European guidelines[10] recommend active standing as the initial test for patients suspected of OH. However, the addition of high-quality heart rate and blood pressure recordings and other monitoring devices such as assessment of cerebral perfusion[32] is cumbersome and thereby more difficult to achieve during active standing than during TT. Furthermore, with a diagnostic goal of inducing previously experienced symptoms, the duration of the upright period must be >20 min and, typically, 35 min.[10] A long duration of active standing cannot be expected to be tolerated by many patients, especially the frail/aged.

Moving from supine to upright posture rarely induces syncope in normal healthy patients but may cause minor worrisome symptoms. For instance, a transient sensation of 'greying out/dizziness/light-headedness/unsteadiness' is common immediately after upright postural change (so-called 'initial' or 'immediate' OH). While usually harmless, this sensation may cause alarm/instability in some patients.[10] Active standing is sufficient to document this problem and initiate treatment. Thus, active standing should be seen as a necessary, complementary aspect of cardiovascular autonomic workup in unexplained syncope, optimally with beat-to-beat haemodynamic monitoring for diagnostic accuracy.

Delayed OH is a far more important clinical problem, especially in older patients, debilitated patients, those with neurogenic OH, or in diseases that affect neurological responses, such as diabetes or alcohol abuse. In these cases, OH may be considerably delayed after change of posture that can result in fall injury. Active standing may not be tolerated for sufficient time to be diagnostic with additional fall injury risk during testing. TT avoids injury risk while providing the possibility of defining the diagnosis.

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