FOLLOW-UP OF ASYSTOLIC EPISODES IN PATIENTS WITH CARDIOINHIBITORY, NEURALLY-MEDIATED SYNCOPE AND VVI PACEMAKER

The occurrence rate of spontaneous asystolic episodes during long-term follow-up in patients with abnormal asystolic responses induced by me ans of vasovagal maneuvers was evaluated. The heart rate of 23 patient s (mean age 64 +/- 12 years; 6 women and 17 men) affected by neurally mediated syncope (mean 4.3 +/- 4.9 episodes) was continuously monitore d by a specially designed implanted pacemaker able to detect and store in its memory all asystolic episodes lasting 3 to 6 or >6 seconds. As ystolic, neurally mediated syncope was diagnosed when a reflex asystol e of >3 seconds was induced during carotid sinus massage (n = 22), eye ball compression test (n = 3) or head-up tilt test (n = 2). During a t otal of 357 months (mean 15 +/- 7) of monitoring, asystolic episodes o ccurred in 17 patients (74%): 1,765 episodes of 3- to 6-second (median 3) duration occurred in 14 patients, and 47 episodes of >6-second (me dian 2) duration occurred in 11. The actuarial estimates of occurrence of asystolic episodes of >3 and >6 seconds were 82 and 53%, respectiv ely, after 2 years of follow-up. Only 12 episodes of 3 to 6 seconds (0 .7%), and 20 episodes of >6 seconds (43%) resulted in presyncopal or s yncopal symptoms. Thus, an asystolic response to vasovagal maneuvers p redicts the occurrence of spontaneous asystolic episodes during follow -up. With few exceptions, spontaneous episodes are asymptomatic and th eir incidence is low.