Gene Variant Linked to Sudden Cardiac Death Risk in Blacks

Roughly 13% of people of African descent may be at risk of potentially fatal heart arrhythmias: study

FRIDAY, May 13 (HealthDay News) -- A common gene variant among black people may be linked to the development of life-threatening heart arrhythmias (when the heart beats too fast, too slow or irregularly), according to a new study.

In pinpointing this gene, Duke University Medical Center researchers hope to one day help doctors determine which patients are likely to benefit most from an implantable cardio-defibrillator (ICD) -- a device that automatically detects and corrects potentially deadly heart rhythms by delivering a jolt of electricity.

Blacks are disproportionately affected by heart failure, arrhythmias and sudden cardiac death, "but are vastly underrepresented in the majority of clinical trials conducted to date," the study's lead author, Dr. Albert Y. Sun, said in a university news release. "Much debate surrounds the identification of patients for ICD implantation, which takes into account efficacy, cost and complication rates."

The study, published in the current issue of the journal Circulation: Cardiovascular Genetics, included 112 black patients who received ICDs for primary prevention of sudden cardiac death. Over a follow-up period that averaged about two years, ICDs were effectively activated in 23 of the patients.

The investigators found that patients with the gene variant, known as the Y1103 allele, were three times more likely have the device triggered because of a potentially life-threatening ventricular arrhythmia. "These findings are significant because approximately 13 percent of people of African descent carry this variant," Sun noted.

Patients with the gene variant also experienced their first arrhythmia 448 days sooner than those without the gene (609 days versus 1,057 days). "This is the largest genetic study to date of blacks with ICDs and it promises potential new diagnostic strategies to define patients who will most benefit from ICDs," concluded the study's principal investigator, Dr. Geoffrey S. Pitt, director of Duke's Ion Channel Research Unit, in the news release.

More information

The American Heart Association offers detailed information on heart arrhythmias.

Mary Elizabeth Dallas SOURCE: Duke University, news release, May 11, 2011

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