A comparison of a single-stage isoproterenol tilt table test protocol with conventional two-staged tilt protocol in patients with syncope.

PURPOSE

Recently, Shen and colleagues described a single-stage isoproterenol protocol: Head Up Tilt Table testing (HUTT). The purpose of this study was to compare the introduction of this single-stage tilt protocol to sequential two-staged tilt table testing.

METHODS

Patients with recurrent or dramatic syncope or near syncope were referred for HUTT. A total of 100 patients underwent HUTT via a two-staged tilt protocol: 60 passive tilt for 30 minutes and, if negative, followed by a 10-minute tilt with isoproterenol titration to a 20% heart rate increase (two-staged HUTT). The next 100 patients underwent single stage isoproterenol protocol, which consisted of a 10-minute, 70 tilt with fixed dose isoproterenol infusion (0.05 ug/kg/minute). Patients with isoproterenol contraindications underwent a passive tilt (40 minutes for a conventional two-staged 60-degree tilt, and 45 minutes for a single-staged 70 tilt.

RESULTS

In the single-stage method, 40% of those that received isoproterenol had a positive test, as compared to 24% for two-stage HUTT protocol (p < 0.001).

CONCLUSION

A single-staged isoproterenol HUTT provides a rapid method of increasing the overall test yield as compared to conventional two-staged HUTT. Further research is necessary to elucidate the overall utility of this rapid single-stage protocol.