Posted on 08/31/2015

First-of-its-dind discovery furthers understanding of role of genetics in sudden cardiac death, may help identify patients at increased risk

LONDON, UK--A gene associated with sudden cardiac death in the general population has been identified using implantable cardioverter defibrillator (ICD) monitoring, according to two independent studies. The research, presented for the first time at European Society of Cardiology (ESC) Congress, included patients from the DISCOVERY trial and Oregon-SUDS trial and discovered that a polymorphism in the GNAS gene predicted ventricular tachyarrhythmias and sudden cardiac death.

“This is the first time a gene has been identified using ICD monitoring and then confirmed to be associated with sudden cardiac death in the general population,” said principal investigator Professor Heiner Wieneke, chief physician in the Department of Cardiology, Contilia Heart and Vessel Centre, St. Marien-Hospital Mülheim, Germany. “Epidemiological studies have suggested that genetic factors contribute to sudden cardiac death but only a few genes have been identified.”

Sudden cardiac death is one of the leading causes of death in Western countries and cardiac arrhythmias have been reported as the cause in many cases. Prior clinical studies have suggested that an individual’s genes may contribute to the risk of cardiac arrhythmias and sudden cardiac death. 

ICDs are indicated for patients who either have survived a life threatening cardiac arrhythmia or have a high risk for sudden cardiac death due to cardiac arrhythmias. An ICD is a small implantable device that is placed under the skin to continuously monitor the heart; if it detects a severe abnormal heart rhythm, known as ventricular arrhythmia, it delivers therapy to restore a normal heartbeat. 

Part one of the study was the DISCOVERY trial, a prospective, international, multicenter study in 1,145 patients who received an ICD for primary prevention of sudden cardiac death. ICDs were used to monitor and store cardiac arrhythmia data to study whether specific genes were associated with an increased risk of potentially life-threatening ventricular tachyarrhythmias. 

In the second part of the study, the genes found to be associated with cardiac arrhythmias in the DISCOVERY trial were evaluated in 1,335 patients from Oregon-SUDS (Sudden Unexpected Death Study), a community-based study analyzing causes of sudden cardiac death in the Portland, Oregon metropolitan area. 

"This is the first time a gene has been identified using ICD monitoring and then confirmed to be associated with sudden cardiac death in the general population," said Professor Heiner Wieneke, principal investigator of the DISCOVERY trial and chief physician in the Department of Cardiology, Contilia Heart and Vessel Centre, St. Marien-Hospital Mülheim, Germany. 

"This research is vital to helping us better understand why some patients are at higher risk of sudden cardiac death, one of the leading causes of death globally," said Sumeet Chugh, M.D., associate director of the Cedars Sinai Heart Institute and lead investigator for Oregon SUDS. "These findings put us one step closer to understanding the complexities of sudden cardiac death and may, someday, help us identify which patients are at risk."  

SOURCE: European Society of Cardiology and Medtronic

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