Novel and highly lethal NKX2.5 missense mutation in a family with sudden death and ventricular arrhythmia.

To date, several disease-related mutations in NKX2-5, a cardiac-specific homeobox gene, have been documented in patients with a variety of congenital heart diseases (CHDs). The most commonly reported phenotypes are secundum atrial septal defect (ASD) and atrioventricular conduction disease (AVCD). Reports of sudden cardiac death (SCD) have been attributed to progressive conduction disease preventable with pacemaker therapy. A retrospective chart review of individuals from three generations of a family with a novel NKX2-5 mutation associated with CHD, ventricular arrhythmias, and SCD despite pacemaker therapy was conducted. The review documented NKX2-5 Gln181His missense mutation in 11 phenotypically affected members of a single family with a strong family history of SCD, CHD, and AVCD. Before genotyping, four family members died suddenly, two despite pacemaker therapy. The ages at SCD were respectively 23, 29, 44, and 45 years. Observed phenotypic characteristics of genotype-positive patients included ASD, ventricular septal defect, aortic coarctation, tricuspid atresia, supraventricular tachycardia, progressive AVCD, and ventricular tachycardia documented on implantable cardiac defibrillator (ICD) recording. The age at presentation ranged from 5 months to 44 years, and AVCD was seen as early as infancy. Four phenotypically unaffected family members tested negative for the mutation. The findings of this review strongly suggest a new association of this NKX2-5 mutation with SCD from ventricular arrhythmia. This observation has significant implications for the choice of therapy for affected individuals, specifically the use of ICDs, and broadens the observed phenotypic spectrum of NKX2-5 mutations.

Ventricular lead redundancy to prevent cardiovascular events and sudden death from lead fracture in pacemaker-dependent children.

BACKGROUND: Children requiring a permanent epicardial pacemaker (PM) traditionally have a single lead placed on the right ventricle. Lead failure in pacemaker-dependent (PMD) children, however, can result in cardiovascular events (CVEs) and death. OBJECTIVE: The purpose of this study was to determine if redundant ventricular lead systems (RVLS) can safeguard against CVE and death in PMD children. METHODS: This was a single-center study of PMD patients undergoing placement of RVLS from 2002-2013. Patients ≤21 years of age who were PMD were included. Patients with a biventricular (BiV) system placed for standard resynchronization indications were excluded. RVLS patients were compared to PMD patients with only a single pacing lead on the ventricle (SiV). RESULTS: Seven hundred sixty-nine patients underwent PM/implantable cardioverter-defibrillator placement with 76 BiV implants; 49 patients (6%) were PMD. Thirteen patients underwent implantation of an RVLS. There was no difference between the RVLS group (n = 13) and SiV PMD control group (n = 24) with regard to age (RVLS 9.5 ± 5.8 years vs SiV 9.4 ± 6.7 years, P = .52), weight (RVLS 38.2 ± 32.6 kg vs SiV 35.2 ± 29.3 kg, P = .62), indication for pacing, procedural complications, or time to follow-up. There were 2 lead fractures (17%) in the RVLS group (mean follow-up 3.8 ± 2.9 years), with no deaths or presentations with CVE. The SiV control group had 3 lead fractures (13%) (mean follow-up 2.8 ± 2.9 years), with no deaths, but all 3 patients presented with CVE and required emergent PM placement. CONCLUSION: RVLS systems should be considered in children who are PMD and require permanent epicardial pacing. BiV pacing and RVLS may decrease the risk of CVE in the event of lead failure in PMD patients.