The influence of sex and age on response to head-up tilt-table testing in patients with recurrent syncope

Background: syncope is a common problem, accounting for 6% of hospital admi ssions. Often a diagnosis is not established. Head-up tilt testing is a dia gnostic test for neuro-cardiogenic syncope, a condition which is often thou ght to affect younger women and be relatively rare in older people. Ve exam ined the effect of sex and age on response to head-up tilt testing in patie nts with unexplained syncope. Methods: we performed a retrospective analysis on consecutive tilt tests pe rformed using the Westminster drug-free protocol from January 1992 to June 1998. Patients were divided into four groups on the basis of sex and age (l ess than or equal to or greater than or equal to 65 years). Responses were classified according to the Vasovagal International Study Investigators' cr iteria. Results: we performed 665 tests in 590 patients. Mean age was 50 years +/- 17.6 (range 12-83). One hundred and fifty-three patients (23%) were > 65 ye ars. There was an almost equal sex distribution. Two hundred and eight test s (31%) were positive, with 113 (54%) showing a mixed response (type 1), 65 (32%) a cardio-inhibitory response (type 2) and 30 (14%) a vasodepressor r esponse (type 3). Age and sex had no effect on rates of positive tests or t ime to positive result. There was no gender influence with respect to respo nse type. However, subjects aged > 65 years had a higher incidence of vasod epressor response (type 3)-29% versus 9% (P < 0.001). Conclusions: head-up tilt testing is a useful tool in the investigation of all patients with suspected neuro-cardiogenic syncope. Age and sex do not i nfluence the likelihood of a positive response, but older patients have an increased frequency of pure vasodepressor responses. This may have implicat ions with respect to treatment strategies.