The purpose of this research is to see if investigators can detect truncated mRNA splice variants of the cardiac voltage-gated sodium (Na+) channel gene, SCN5A, in patients with a weak heart (Heart Failure) with or without an implantable cardioverter-defibrillator (ICD) and compare them to patients with a normal heart. Hypothesis: 1. Patients with reduced left ventricular ejection fraction have increased abundances truncated mRNA splice variants of the SCN5A gene, which portends to sodium channel dysfunction and an increased risk for sudden cardiac death. 2. Patients with implantable cardioverter-defibrillator devices (ICDs) who have experienced shock therapy have increased abundances of truncated mRNA splice variants of the SCN5A gene compared to similar congestive heart failure patients who have not experienced shock therapy.

NCT01185587

Conditions

1. Atrial Fibrillation
2. Atrial Flutter
3. Heart Failure

MeSH:Heart Failur Heart Failure Atrial Fibrillation Atrial Flutter

HPO:Abnormal left ventricular function Atrial fibrillation Atrial flutter Congestive heart failure Paroxysmal atrial fibrillation Right ventricular failure

A different SCN5A gene abnormality, the E161K mutation, has been shown to lead to decreased sodium current density and a an 11.9 mV positive shift in the cell membrane half-maximal activation potential.11 --- E161K ---