ICD group for Sudden Cardiac Death

Congestive heart failure (CHF) represents a major health care concern in the United States. Currently, risk stratification of sudden cardiac death and the need for implantable cardioverter-defibrillator (ICD) placement are essentially dependent upon assessment of left ventricular ejection fraction (LVEF). Nevertheless, the predictive value of LVEF is suboptimal, alternative testing for risk assessment for the development of sudden cardiac death in the heart failure population is desirable. At the genome level, the investigator has focused on the role of SCN5A gene mutations in arrhythmogenesis. Lymphocyte SCN5A mRNA processing may serve as a surrogate marker to assess SCN5A function at the cardiac level and may correlated with arrhythmic risk in high risk populations. This study will determine if SCN5A variant levels are predictive of appropriate ICD therapies in patients with a newly implanted ICD.