Original Articles
Indications, methodology, and classification of results of tilt-table testing1

https://doi.org/10.1016/S0002-9149(99)00692-XGet rights and content

Abstract

Tilt-table testing has become an important part of the evaluation of patients with unexplained syncope, although not every patient with vasovagal syncope requires it. Studies have attested to the effectiveness of the technique for providing direct diagnostic evidence of a patient’s susceptibility to vasovagal syncope. This article reviews the need for tilt-table testing and the recommended methods for performing a test. In addition, a detailed classification of the hemodynamic patterns of collapse displayed over the course of a tilt-table study is provided. These distinctive collapse patterns document the evolution of a syncopal event and are particularly important to identify because they can influence the selection of therapy.

Section snippets

Rationale for tilt-table testing

Tilt-table testing is a provocative test used to determine a patient’s susceptibility to vasovagal syncope. The provocation is rather simple: an orthostatic stimulus causes blood to pool in the lower extremities and, in susceptible individuals, vasovagal syncope often ensues within approximately 20 minutes. The triggering mechanism in vasovagal syncope is thought to result from a relatively central hypovolemia, which occurs because of blood pooling in the lower extremities. The afferent end of

Who needs a tilt-table test?

In 1996, the American College of Cardiology published an Expert Consensus on the use of tilt-table testing in the evaluation of patients with unexplained syncope.2 There is general agreement that tilt-table testing should be done in patients with recurrent syncope or in high-risk patients after a single syncopal episode. Tilt-table testing is used primarily in patients without structural heart disease for whom the diagnosis of syncope is not evident from the history and who have a negative

Methodology

There are numerous variations in the methods used for tilt-table testing—a review of which is beyond the scope of this article.1, 2, 3, 9, 10 Tilt-table tests are often done in 2 stages: a prolonged period of head-up tilt in the drug-free state, followed by a shorter period of head-up tilt after administration of a provocative pharmaceutical agent. We believe that the most valuable information is obtained during drug-free passive tilt.

Tilt-table testing should be performed in a quiet,

Patterns of collapse during tilt-table testing

In this section, we describe different patterns of hemodynamic collapse that illustrate the pathophysiologic evolution of syncope (Figure 1). These patterns are displayed over the course of tilt-table studies and, in our opinion, suggest specific approaches to therapy. It is important to distinguish the hemodynamic pattern of vasovagal syncope from the dysautonomic response to head-up tilt and from the response seen in patients with postural orthostatic tachycardia syndrome (POTS), because the

Discussion

We have described several different hemodynamic responses that can occur during tilt-table testing. This system builds on the initial classification of the subtypes of vasovagal syncope proposed by the VASIS investigators 7 years ago.8 Here, we expand the previous classification to include 2 important responses to tilt-table testing that should be distinguished from the vasovagal syncope responses: a dysautonomic response and POTS. These disorders likely represent responses to upright posture

References (25)

  • A. Fitzpatrick et al.

    Echocardiographic and endocrine changes during vasovagal syncope induced by prolonged head-up tilt

    Eur J Pacing Electrophysiol

    (1992)
  • T. Klingenheben et al.

    Changes in plasma epinephrine concentration and in heart rate during head-up tilt testing in patients with neurocardiogenic syncopecorrelation with successful therapy with beta-receptor antagonists

    J Cardiovasc Electrophysiol

    (1996)

    • Cited by (0)

    1

    This article may contain discussion of off-label or investigational uses (not yet approved by the FDA) of various therapeutic agents. Please refer to the box provided on page 2Q of this supplement for a disclosure of such agents.

    View full text
    Copyright © 1999 Excerpta Medica Inc. All rights reserved.