Genetic variation discovered for sudden cardiac arrest

Kathleen Blanchard's picture
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Research has uncovered a gene variation that may double the chance of sudden cardiac arrest. The condition, which is a sudden cessation of heartbeat, was linked to a variation in the BAZ2B gene

The condition, which is a sudden cessation of heartbeat, strikes 250,000 to 300,000 people in the U.S. each year. Worldwide, up to 5 million people experience the defect in the heart’s electrical impulses annually that leads to death in 95 percent of individuals.

Senior author Sumeet S. Chugh, MD, associate director of the Cedars-Sinai Heart Institute and a specialist in cardiac electrophysiology explains the importance of the discovery: "If we wait until someone has a sudden cardiac arrest, it is usually too late for treatment. That is why knowing who is genetically susceptible is so important."

Cardiac arrest that happens suddenly can occur in healthy individuals and without warning from heart rhythm disturbance. Causes are abnormally slow, too rapid or irregular heartbeat.

Patients identified at risk for sudden cardiac arrest can be protected with implantable cardiac defibrillators that restore heart rhythm immediately.

But many, it happens without warning. In hospitals and in the community external defibrillators ‘shock’ the heart back into rhythm. The procedure, performed with external defibrillator paddles or an automated external defibrillators (AED) must performed within minutes.

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Researchers from the Cedars-Sinai Heart Institute, Johns Hopkins University School of Medicine, along with researchers from the National Institutes of Health, Harvard University, Wake Forest University School of Medicine, Oregon Health and Science University, Finland, Canada and the Netherlands conducted a genome-wide study to find the association between the BAZ2B gene variant and sudden cardiac arrest.

In this study DNA of 4,402 subjects who had suffered cardiac arrest was compared to the DNA of 30,000 individuals who had no history of the disorder.

The genetic variation in the BAZ2B gene was associated with a significantly higher chance of the condition.

"If you have this genetic variation in your DNA, it appears that you may have a two-fold higher likelihood of sudden cardiac arrest,"
said Chugh, adding, "We are at the beginning of unraveling the mystery of what causes sudden cardiac arrest and how to prevent it."

The researchers hope understanding the genetic variation will help pinpoint those at risk for sudden cardiac arrest.

Citation:
Arking DE, Junttila MJ, Goyette P, Huertas-Vazquez A, Eijgelsheim M, et al. (2011)
"Identification of a Sudden Cardiac Death Susceptibility Locus at 2q24.2 through Genome-Wide Association in European Ancestry Individuals"
PLoS Genet 7(6): e1002158. doi:10.1371/journal.pgen.1002158

Image: An ECG lead showing ventricular fibrillation.
Credit: Wikimedia Commons

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