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

Syncope and Tilt Testing

Tilt-table testing was introduced into clinical evaluation of TLOC of unknown aetiology to assess susceptibility to vasovagal reflex. Such testing is unnecessary for diagnosis if medical history is classical and diagnostic of reflex syncope. However, that is often not the case, especially in older patients in whom the history may be inadequate due in part to retrograde amnesia in these older fainters.[23]

TLOC has four features that can be derived from history taking: (i) tendency to fall as expression of loss of motor control; (ii) amnesia for duration of TLOC; (iii) abnormal responses to speech/touch; and (iv) short duration (<5 min).

TLOC differential diagnosis includes: (i) concussion, (ii) syncope; (iii) epileptic seizures; (iv) psychogenic spells resembling syncope [psychogenic pseudosyncope (PPS)] or seizures [psychogenic non-epileptic seizures (PNES)]; and (v) intoxication/metabolic disturbance (strictly not TLOC as duration is >5 min).

Distinction between these diagnostic entities by careful medical history including eyewitness reports is often but not always possible.

In some patients with recurrent apparent syncope, in whom previous attempts have failed to establish a diagnosis, TT is the best next step and guidelines support this strategy.[10,11] For example, if PPS, PNES, or mechanical falls due to orthostatic intolerance are possible explanations, observations during TT are likely to be diagnostic. Concomitant use of electroencephalography (EEG) is readily added to TT and is considered essential in PPS/PNES.[24] In OH, TT allows safe prolonged blood pressure assessment without risk of falls and injury such as might occur during active stand or squat-stand tests. However, TT is less effective than active standing for documenting immediate OH, where the latter is recommended.[10,11]

Multiple observations suggest that reported syncope/collapse associated with positive TT is comparable with spontaneous vasovagal syncope (VVS), although it should be accepted that tilt-induced syncope is not identical to the spontaneous attack. For example, the bradyarrhythmias seen on implantable loop recorders (ILR) are more prominent than during TT.[6] However, VVS diagnosis from TT is based on the patient-recognizing symptom reproduction (Figure 1). Thus, TT can play an important role in VVS diagnosis but much less in therapy selection.[5,10,11,25]

Figure 1.

Courtesy of Artur Fedorowski MD and Fabrizio Ricci MD (Malmo, Sweden) depicting blood pressure (upper traces) and heart rate (lower trace) during a head-up tilt test-induced mixed collapse pattern of vasovagal faint. In this case, nitroglycerin was administered sublingually after 20 min of passive upright posture proved non-diagnostic. The expanded images illustrate the collapse using the same format beginning with administration of nitroglycerin; events, prodrome, syncope, tilt-down and awakening are labelled. Time base is shown between the left two panels in minutes. The scales are blood pressure 0–150mmHg and heart rate 0–150 bpm.

The Fainting Assessment Study (FAST),[25] the clinical study of Wieling et al.,[26] and the review of Sutton et al.[27] reported a diagnostic yield of ~60% achieved by hospital physicians. The review later showed the diagnostic yield rises from 60% to 70% by hospital physicians following ESC guidelines to 85% in syncope units where TT, albeit not applied in all cases, and expert history taking and interpretation are available.[25–27]

Finally, clinicians caring for syncope/collapse victims realize that in patients of all ages, recurrent unexplained syncope/collapse may provoke considerable anxiety in those affected and their families. In the case of faints due to VVS/OH/PPS, the patient's understanding that the physician or highly trained assistant[28] has witnessed their attack and, thereby, has a firm diagnosis is greatly reassuring. TT offers this opportunity.

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