Tilt table testing of young adult patients: improved speed and sensitivity using an isoproterenol bolus and a continuous 60 degrees tilt.

ABSTRACT

The tilt table is a diagnostic device used to induce vagal syncope and determine etiology. Sensitivity enhancing techniques, such as the administration of isoproterenol, can be applied to children and young adults to compensate for the otherwise low sensitivity (20%-30%) observed in that population. This study describes an improved test that offers a simplified approach while decreasing the amount of time involved by up to 50%, without compromising sensitivity. This 45-minute procedure relies on sensitization with isoproterenol administered as a 2- to 80 micrograms bolus instead of a continuous infusion. The isoproterenol is injected at the 30th minute of a 45-minute 60 degrees tilt test without returning the patient to the supine position. In this study, the isoproterenol bolus tilt test was found to be "positive" in 24 of 30 patients reporting unexplained syncope 10 cases before the 30th minute (11.2 +/- 8.4 min) and 14 cases after administration of 5.1 +/- 1.9 micrograms of isoproterenol.