Idiopathic Postural Orthostatic Tachycardia: A Variant of Neurocardiogenic Syncope?

Abstract

Transient episodes of neurocardiogenically-mediated hypotension and bradycardia have become a well-recognized cause of recurrent syncope and near-syncope [1]. The emergence of tilt table testing as a reliable method for provoking these periods of autonomic decompensation not only provided a useful diagnostic tool but also allowed for a much better understanding of the pathophysiology of these disorders. In the course of investigations, it became apparent that these episodic alterations in autonomic tone could result in varying degrees of systemic hypotension that, while not sufficiently large to cause complete loss of consciousness, were nevertheless great enough to cause symptoms such as near-syncope, lightheadedness, vertigo, and transient ischemic attacks. At the same time, we and other groups identified a large subgroup of patients who have a less severe form of orthostatic intolerance that is characterized by postural tachycardia, exercise intolerance, disabling fatigue, lightheadedness, dizziness, and blurred vision [2]. Detailed investigations of these patients showed that the histories, physical findings, and responses to postural change and head-up tilt were essentially similar. This disorder has become generally known as the postural orthostatic tachycardia syndrome. The present paper will review the clinical characteristics, their responses during head-upright tilt table testing, and the various therapies that can benefit these patients.

“All beginnings are hard… ”

The Talmud