Cardiac Arrhythmia

CardioDx and leading cardiologists are conducting an ongoing, prospective, multi-center clinical study in cardiac arrhythmia called DISCERN (Diagnostic Investigation of Sudden Cardiac Event Risk). The DISCERN study aims to develop and validate a genetics-based noninvasive test that will help identify ejection-fraction (EF) compromised patients at risk for sudden cardiac arrest (SCA). Cardiac arrhythmias are disturbances in normal heart electrical activity that alter heart rhythm and cause the heart to beat too fast, too slow, or irregularly.  SCA from lethal ventricular arrhythmias is a leading cause of mortality, responsible for up to half a million deaths annually in the U.S. and for approximately half of all mortality in patients with heart failure.1-3 Establishing an individual’s risk for severe arrhythmias before a life-threatening event occurs remains a significant medical challenge. A genomic test may provide cardiologists a decision-making tool that will identify patients who would benefit most from an implantable cardioverter defibrillator (ICD).

Cardiac arrhythmias may be precipitated by a complex interaction of genetic and environmental factors. Establishing increased risk for arrhythmias before a severe life-threatening event is critically important, so that appropriate preventive strategies can be implemented. Several genetic mutations associated with rare, inherited arrhythmia disorders have been identified.4 The aim of the DISCERN study is to identify novel genetic and other biological markers that distinguish patients at increased risk for lethal ventricular arrhythmias in a broader population.5

Initial results on a genome-wide association study on 658 patients from the DISCERN study were reported at the American Heart Association meeting in 2010.6

Further work to replicate and extend these findings are in progress.

For more information about the DISCERN study, see clinicaltrials.gov.7
  1. Zheng Z-J, Croft JB, Giles WH, Mensah GA.  Sudden cardiac death in the United States, 1989 to 1998.  Circulation 2001;104:2158–63.
  2. AHRQ Research Activities, December 2002. Researchers examine the risk factors for sudden cardiac arrest and management of at-risk patients. Rockville, MD: Agency for Healthcare Research and Quality, Office of Healthcare Information.
  3. MMWR Morb Mortal Weekly Rep 2002 Feb 15;51;123–6. State-specific mortality from sudden cardiac death—United States, 1999.
  4. Vincent GM, Timothy KW, Leppert M, Keating M. The spectrum of symptoms and QT intervals in carriers of the gene for the long-QT syndrome. N Engl J Med. 1992;327:846–852.
  5. Jouven X, Desnos M, Guerot C, Ducimetière P. Predicting sudden death in the population: the Paris Prospective Study I. Circulation. 1999;99:1978–1983.
  6. Hranitzky PM, Sehnert AJ, Blanchard JL, et al. Abstract 16410: Identification of novel genetic markers associated with lethal ventricular arrhythmias in heart failure patients: genome wide association study in the DISCERN cohort. Circulation. 2010;122. Abstract 16410.
  7. DISCERN trial. Clinical trial summary found at: www.clinicaltrials.gov, NCT00500708.