Vagotonia in infants, children, adolescents and young adults.

Twenty-four patients with various manifestations of increased vagal tone were seen between 1975 and 1981. Three distinct groups could be identified by clinical characteristics and to some extent by age. The first group showed evidence of prolonged atrioventricular conduction on their electrocardiograms but were asymptomatic. The others presented with syncope, the etiology of which was determined to be vasovagal. Some patients were older and more athletic. They suffered from syncope associated with exercise or heavy exertion. The youngest patients, however, experienced frequent prolonged episodes of syncope often mistaken for seizures. Treatment for the older patients with syncope consisted mainly of behavior modification, while 5 out of 6 younger patients required the implantation of a ventricular demand pacemaker to prevent repeated and problematic recurrences of syncope.