[Unusual case of orthostatic tachycardia]

Orthostatic intolerance and postural tachycardia are common complaints, often caused by hypovolemia, antihypertensive medications, diuretics or alcohol. These symptoms could also be related to autonomic failure. Although upright posture renders patients more susceptible to provocation of supraventricular tachyarrhythmias in the electrophysiologic laboratory, orthostasis by itself seldom enough for the induction of such arrhythmias. The authors hereby present a patient, whose AV nodal reentry tachycardia could be provoked by head-upright tilting. Vagal maneuvers could terminate the tachycardia by decreasing the conduction in the slow anterograde pathway, however these maneuvers were successful only after assuming supine posture. The authors' report illustrates the role of autonomic influences, and the mechanism of vagal maneuvers in terminating this common arrhythmia.