Transient third-degree atrioventricular block in a 4-year-old child with familial dysautonomia

Documented transient third-degree atrioventricular block and asystole in a child with familial dysautonomia

An 11-year-old boy with familial dysautonomia presented with palpitations. Continuous 24-h Holter monitoring revealed intermittent high-grade atrioventricular block and asystole. The unopposed parasympathetic tone in patients with dysautonomia may make them susceptible to bradycardia and atrioventricular block. We recommend routine 24-h Holter monitoring screening and, when indicated, consideration of pacemaker implantation to reduce the high risk of sudden death phenomena in this patient population.

Pacemakers in patients with familial dysautonomia--a review of experience with 20 patients

Familial dysautonomia (FD) is a genetic disease associated with a high incidence of sudden death. If fatal bradyarrhythmia is an etiological factor then the incidence of sudden death should decrease after pacemaker placement. Retrospective review of 596 registered FD patients revealed that 22 FD patients (3.7%) had pacemakers placed between December 1984 and June 2003. Clinical and electrocardiographic indications for placement and demographic data were assessed for 20 of the 22 patients (10 males, 10 females, ages 4 to 48 years). Two patients were excluded because of insufficient data. Prior to pacemaker placement, presenting symptoms were syncope and cardiac arrest, 16/20 (80%) and 6/20 (30 %), respectively. Asystole was the most frequent electrocardiographic finding and was documented in 17/20 patients (85 %). Other electrocardiographic abnormalities included bradycardia, AV block, prolonged QTc and prolonged JTc. The average duration of pacemaker utilization was 5.7 years (range 5 months to 14.5 years). Complications included infection (1 patient) and wire migration (2 patients). In the one patient with infection, the pacemaker was permanently removed. This patient then experienced multiple syncopal episodes and death. There were 7 other deaths. Three deaths occurred suddenly without preceding events, and 4 patients had non-cardiac causes of death. None of these 7 deceased patients had recurrence of syncope after pacemaker placement. In the 12 surviving patients, 6 had recurrence of syncope but none had cardiac arrest. Pacemaker placement may protect FD patients from fatal bradyarrhythmia and may decrease the incidence of syncope. However, data are limited and prospective analysis is needed.