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

OBJECTIVES This study was conducted to develop 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 procedural time of single-stage isoproterenol tilt table protocol. METHODS single-stage isoproterenol tilt table test was compared with the passive tilt table test. The study was prospectively designed in randomized and crossover fashion. RESULTS The study population consisted of 111 patients with history of syncope (mean age 55 ± 20 years). Of the total, 62 patients (56%; 95% confidence interval, 46% to 65%) had positive vasovagal response during isoproterenol tilt table testing and 35 (32%; 23% to 41%) during passive tilt table testing (p = 0.002). The mean procedural times of the study population were 11.7 ± 3.6 min and 36.9 ± 13.3 min for isoproterenol and passive tilt table testing, respectively (p < 0.001). All patients tolerated single-stage 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 effective in inducing positive vasovagal response in an adult population than the standard passive tilt table test, and it significantly reduced the procedural time. The increase in positive yield was associated with moderate decrease in apparent specificity. These observations support the conclusion that single-stage tilt table testing could be reasonable diagnostic option in patients undergoing syncope evaluation.