Fast tilt test, a new paradigm in the management of reflex syncope

Abstract

Introduction: Between 20% and 30% of the population present syncope throughout their lives beingreflex syncope the most common cause. The differential diagnosis is based on the characteristics of the episode questionnaire and on the reproducibility of symptomswith the head-up tilt test. However, the tilt test has important limitations, whichhave led us to explore a new parameter in successive stages of research, which wecalled “time delay of the carotid pulse wave”.

Objectives: To present the results of the research on the discovery, development and clinical applicability of the parameter: “time delay of the carotid pulse wave”, capable ofidentifying patients with reflex syncope.

Methods: The development of the idea and the results of the analysis of the correlation between the parameter and the tilt test evaluated in a pilot study of 43 patients with syncope are described. The correlation is confirmed in 100 patients with syncope andin controls; the pathophysiological mechanism of the parameter is evaluated; thedesign of an automated device is described and its validation is confirmed in a multicenter study of 100 patients with history of syncope using drug-stimulated head-uptilt test. The search of a new gold standard for reflex syncope is described.

Results: The statistical analysis performing univariate and multivariate models and the construction of ROC curves on 243 patients undergoing head-up tilt test showed that, despite the different ages or methods used, the parameter correctly classified morethan 80% of patients with history of syncope and positive head-up tilt test and 100% of volunteers without history of syncope who presented positive head-up tilt test. The measurement of the parameter without using a tilt table identified 100% ofvolunteers with history of syncope (7/30).

Conclusions: We developed a simple and non-invasive measurement parameter, capable of predicting a positive head-up tilt test within 5 minutes in patients with syncope and ofidentifying people with history of syncope without using the tilt table. The parameter could help to make rapid diagnostic decisions in patients with syncope, to understand the pathophysiological aspects and to evaluate the therapeutic interventions