Age and gender differences in basal and isoprenaline protocols for head-up tilt table testing

Syncope is a common occurrence, the prevalence of which increases with age, and among the multiple causes of syncope, neurally mediated syncope is thought to be a frequent cause in the young and in the elderly. Head-up tilt table testing (HUT) has become the diagnostic test of choice for neurally mediated syncope, the response to which varies clearly with age. The purpose of this study is to report the differences among patients suffering syncope referred for HUT, and the influence of age and gender on HUT results (percentage of positive responses and response patterns) in two study protocols (basal and isoprenaline).

One thousand, two hundred and nineteen patients with syncope were referred to the authors' Cardiology Department for HUT from September 1990 to April 2000; 1061 undergoing basal HUT (Group A) and 158 undergoing isoprenaline tilt table testing (Group B). Complications were noted in neither protocol. Females were more frequent among young people, and males in the elderly (P<0.05). Head-up tilt table testing was abnormal in 259 (24.4%) patients in Group A and in 85 (53.7%) patients in Group B (P<0.05), and no gender differences were observed. The positive rate of tests in men and women significantly declined with age in Group A (P<0.05), but not in Group B (P=ns). There were no differences in the patterns of haemodynamic collapse in both groups.

In the study of syncope, basal HUT has a high positive rate in young people; a decrease in positive rate with age suggests, however, the need for using another protocol with a similar diagnostic accuracy in the elderly.