Utility of a single-stage isoproterenol tilt table test in adults - A randomized comparison with passive head-up tilt

OBJECTIVES This study was conducted to develop a time-efficient tilt table test. BACKGROUND Current protocols of tilt table testing are quite time-consuming . This study was designed to assess the diagnostic value, tolerance and pro cedural time of a. single-stage isoproterenol tilt table protocol. METHODS A single-stage isoproterenol tilt table test was compared with the passive tilt table test. The study was prospectively designed in a randomiz ed and crossover fashion. RESULTS The study population consisted of 111 patients with a history of sy ncope (mean age 55 +/- 20 years). Of the total, 62 patients (56%; 95% confi dence interval, 46% to 65%) had a positive vasovagal response during isopro terenol tilt table testing and 35 (32%; 23% to 41%) during passive tilt tab le testing (p = 0.002). The mean procedural times of the study population w ere 11.7 +/- 3.6 min and 36.9 +/- 13.3 min for isoproterenol and passive ti lt table testing, respectively (p < 0.001). All patients tolerated single-s tage isoproterenol testing. In the 23 control subjects (mean age 34 +/- 11 years), the apparent specificities were 91% (72% to 99%) and 83% (61% to 99 %) for passive and single-stage tilt table testing, respectively. CONCLUSIONS The single-stage isoproterenol tilt table test was more effecti ve in inducing a positive vasovagal response in an adult population than th e standard passive tilt table test, and it significantly reduced the proced ural time. The increase in positive yield was associated with a moderate de crease in apparent specificity. These observations support the conclusion t hat single-stage tilt table testing could be a reasonable diagnostic option in patients undergoing syncope evaluation. (J Am Coil Cardiol 1999;33:985- 90) (C) 1999 by the American College of Cardiology.