Pacemakers in patients with familial dysautonomia

Abstract

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.

Cardiac sympathetic hypo-innervation in familial dysautonomia

“…Patients with FD seem to have an increased risk of tachy-and brady-arrhythmias, asystole, and sudden death [5,6,18]. Our finding of cardiac hypoinnervation provides a possible explanation for arrythmias in FD.…”

Cardiac pacing in patients with familial dysautonomia

“…Nevertheless, the mortality (either sudden and all-cause) of the implanted FD patients did not differ from that observed among the general FD population during the same monitoring period [18]. These data seem to contradict the original hypothesis of a bradycardia-related sudden death among FD patients and argue against a specific role of cardiac pacing in this clinical setting.…”

“…This hypothesis is correctly addressed by the authors -"hypoxia in FD patients is known to result in profound central depression that could irrevocably compromise cardiac function and would be unresponsive to pacing" - [18] and is object of ongoing research. Although the above-mentioned breathing irregularities might occur during sleep as well CAR 242 A.…”

“…In this issue of Clinical Autonomic Research [18], Gold-von Simson et al address the hypothesis that in these patients sudden death might be related to bradycardia, and thus could be prevented by means of permanent cardiac pacing. The rationale of the study is based on the consideration that FD causes a near-selective decrease in sympathetic innervation, thus, exposing patients to exaggerate, unopposed vagal responses including cardiac bradyarrhythmias [3,37].…”

“…In effect the population of the study is quite heterogeneous, consisting of patients with a bradycardia-related syncope (spontaneous recovery) or cardiac arrest (need for resuscitation), but with a large prevalence of subjects with recurrent syncope [18]. In such a clinical setting, a pacemaker implantation is warranted also independently from the presence of FD [19], but this does not mean that all these patients are at increased risk for sudden death.…”