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

Abstract

OBJECTIVESThis study was conducted to develop a time-efficient tilt table test.BACKGROUNDCurrent protocols of tilt table testing are quite time-consuming. This study was designed to assess the diagnostic value, tolerance and procedural time of a single-stage isoproterenol tilt table protocol.METHODSA single-stage isoproterenol tilt table test was compared with the passive tilt table test. The study was prospectively designed in a randomized and crossover fashion.RESULTSThe study population consisted of 111 patients with a history of syncope (mean age 55 ± 20 years). Of the total, 62 patients (56%; 95% confidence interval, 46% to 65%) had a 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.CONCLUSIONSThe single-stage isoproterenol tilt table test was more effective in inducing a 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 a moderate decrease in apparent specificity. These observations support the conclusion that single-stage tilt table testing could be a reasonable diagnostic option in patients undergoing syncope evaluation.