Tilt-table testing and syncope

Syncope is a common clinical problem with multiple potential causes. Recent studies have delineated the natural history and most frequent causes of recurrent syncopal episodes. The medical history and detailed physical examination are particularly important. Clinical electrophysiologic testing has also played a critical role in assessing causes of syncope, but recent reports suggest that its value lies primarily in treating patients with evident underlying structural heart disease. Among patients without structural heart disease, the neurally mediated forms of syncope, particularly the emotional or vasovagal faint, are by far the most common basis for symptoms. In these patients, head-up tilt-table testing has proved particularly valuable in defining the origin of the problem and in assessing therapeutic alternatives. Protocols for upright tilt-table testing remain in evolution. Nonetheless, current practice suggests that 25-minute tilt-test duration is reasonable if pharmacologic provocation is to be used for further evaluation of patients with negative initial findings. However, for those laboratories that do not favor pharmacologic intervention, a 45-minute tilt-test duration is probably essential. Overall, tilt-table testing has proved relatively sensitive and appropriately specific for the identification of patients susceptible to neurally mediated syncopal syndromes.