The effects of aging on the results of prolonged
drug-free tilt testing were studied in 175 consecutive patients with unexplained
syncope divided into 3 groups: 59 patients < 40 years old; 57 patients between 40 and 60 years; and 59 patients > 60 years old. Tilt-induced vaso-vagal
syncope occurred respectively in 17 (29%), 20 (35%), and 18 patients (31%) in the 3 age groups. Vasodepressor, mixed, and cardioinhibitory vaso-vagal
syncope occurred similarly in the 3 groups; organic
heart disease and systemic
hypertension were more frequent in elderly patients without affecting the incidence of tilt-induced
syncope. Blood pressure and heart rate variations during
syncope were similar in the 3 age groups; in the first 20 minutes of tilt testing, before the appearance of the vaso-vagal reflex, elderly patients showed greater reduction in blood pressure and smaller increase in heart rate than younger patients. Our data indicate that increasing age determines a different blood pressure and heart rate behavior during tilt testing, but apparently does not influence the incidence of vaso-vagal
syncope in patients with
syncope of undetermined etiology. As the proportion of patients with a positive
isoproterenol tilt test was reported to decline with age, our results suggest that the reduced incidence of
syncope during
isoproterenol tilt testing could be the expression of impaired autonomic response among elderly
syncope patients.