Tilt‐Table Testing in the Evaluation of Syncope

The vasovagal or “common” faint is both the most frequent of all forms of syncope and by far the predominant cause of fainting in otherwise healthy individuals.1,2 Establishing a diagnosis of vasovagal syncope is usually possible by careful review of the patient’s medical history, with particular attention being directed to the history of events immediately surrounding the loss of consciousness spells. Specifically, the physician must address the clinical circumstances associated with the onset of loss of consciousness, as well as symptoms both accompanying the faint itself and occurring during the recovery period. The “classic” vasovagal faint is often triggered by identifiable circumstances (e.g., unpleasant sights, emotional upset, pain, prolonged upright posture, hot crowded environments), and after recovery the victim frequently complains of a persistent sense of feeling fatigued. Additionally, eye-witness observations should be sought by the physician in order to help to complete the clinical picture of the symptomatic events. The bystander may report the vasovagal fainter to have been pale and “clammy,” or to have complained of feeling nauseated or generally unwell. However, in many cases (and especially in older individuals) the “classic” markers of vasovagal syncope are absent, and historical features alone are inadequate to establish a confident diagnosis. In such cases, even the experienced clinician may desire additional diagnostic evidence in order to feel comfortable. Moreover, the fainter may develop a greater sense of confidence in the physician’s diagnosis if additional evaluation is obtained, particularly if that evaluation permits reproduction of the patient’s symptoms at a time when these symptoms can be witnessed by the medical practitioner. At present, head-up tilt (HUT) table testing is the only clinical laboratory technique recommended for unmasking susceptibility to the vasovagal faint in patients with unexplained syncope.1,2 As such, it should be available in all centers offering “expert” management for syncope and “falls” victims. However, like any other medical laboratory procedure, HUT is not without potential for inaccurate results and misinterpretation of observations. The most important rule is to consider the possibility of life-threatening causes of syn-