Syncope recurrence can better be predicted by history than by head-up tilt testing in untreated patients with suspected neurally mediated syncope

Abstract

Background. Head-up tilt testing is widely used in the evaluation of patients with suspected neurally mediated syncope. Although it remains unclear which patients require medical therapy to prevent recurrent syncope, most centres initiate empiric medical therapy in all patients in whom neurally mediated syncope has been diagnosed. To determine the natural history of this condition, we followed 80 untreated patients. Methods. All 80 study patients fulfilled the following inclusion criteria: (1) ≤ 1 syncope in the upright position, (2) absence of structural heart disease, (3) unremarkable work-up for other known causes of syncope. Thirty-nine patients had a history of one episode of syncope (group A) and 41 ≤ 2 episodes of syncope (group B). Head-up tilting was performed in all patients at 60°for a maximum of 45 min without medical provocation ('Westminster Protocol'). Results. Suspected neurally mediated syncope could be reproduced by tilt testing in four of 39 patients from group A vs 10 of 41 patients from group B (10% vs 24%, P = 0.1). Independent of the result of head-up tilt testing, all patients were prospectively followed without medical therapy. During 23 ± 8 months follow-up, syncope recurred in four of 39 group A patients vs ≤ 2 of 41 group B patients (10% vs 54%, P < 0.05). The incidence of syncope during follow-up was not significantly different between patients with and without positive baseline tilt test (43% vs 30%, P = ns). Conclusions (1) 90% of patients with a single episode of syncope remain free of recurrent syncope without medical therapy irrespective of the result of tilt testing. (2) About half of patients with a history of ≤ 2 syncopal episodes have recurrent syncope and, thus, may be appropriate candidates for prophylactic medical therapy. (3) Although head-up tilt testing at 60°for up to 45 min does not appear to be useful to predict recurrent syncope in untreated patients, it is still a useful test in its evaluation.