244 High incidence of AV block and prophylactic pacing in familial amyloid polyneuropathy

Abstract

Familial amyloid polyneuropathy (FAP) is an autosomic dominant inherited disease. FAP cardiopathy is characterized by conduction disorders, denervation, and cardiac infiltration. Because of the risk of high degree atrioventricular (AV) block and sudden death, prophylactic pacing can be suggested when there is evidence of amyloid infiltration of the AV conduction pathways. Our purpose was to estimate prevalence of AV block and pacing dependence for high risk FAP patients. In a cohort of 51 FAP patients, we performed standard ECG and electrophysiological study. Patients with conduction disorders underwent prophylactic pacing. During follow up, AV conduction was studied by using data from the Holter memories of pacemakers. Baseline characteristics of the patients are summarized on table 1. During the follow up, permanent high degree AV block occurred in 23.5% of the patients (12/51)(cf. fig. 1). Average percentage was 23 ± 35% for ventricular pacing and 18 ± 24% for atrial pacing. Paroxystic AV block was recorded for all patients but 3 (94%). Prevalence of AV conduction disorders was 283 ± 465 events per month (epm) and was distributed in 14 ± 46 epm for third degree AV block, 195 ± 386 epm for second degree AV block, 73 ± 225 epm for first degree AV block and 0.2 ± 0.7 epm for pauses. During the study, sustained atrial arrhythmias occurred in three patients. No sustained ventricular arrhythmia was recorded. Patients with FAP cardiomyopathy present high incidence of AV blocks. For FAP patients with involvement of the AV conduction pathway, prophylactic pacemaker insertion should be performed. Incidence of permanent AV block Table 1: Baseline characteristics Mean ± SD age (years) 54 ± 13 % of men 64.7% Lenght of fu (months) 34 ± 33 % Val30 Met 64% Surface ECG Conduction disorders 74% AVB type 1 38% PR interbal (ms) 191 ± 41 QRS interval (ms) 94 ± 21 Electrophysiological study corrected sinus recovery time (ms) 546 ± 438 AH interval (ms) 117 ± 43 HV interval (ms) 68 ± 11 Anterior Wenckebach point (bpm) 128 ± 33