African Americans with hypertension, a.k.a. high blood pressure, are twice as likely as whites or other racial groups with the same condition to suffer sudden cardiac death, according to a new study published in the journal HeartRhythm and reported in a Heart Rhythm Society statement. This twofold risk is not a result of other common risk factors such as age, gender, family history and pre-existing heart disease.

Sudden cardiac death (SCD) can occur when the heart unexpectedly stops beating, causing blood flow to the organs and brain to stop. (If timely CPR or defibrillation—when a powerful electric shock is sent through the heart to restart it—is applied, this can quickly restore blood flow and stop SCD.)

To determine if black hypertensive patients have a higher risk of sudden cardiac death, researchers conducting the Losartan Intervention For Endpoint Reduction (LIFE) in Hypertension study examined the hearts of 533 black and 8,660 non-black hypertensive patients with left ventricular hypertrophy (LVH), which had been diagnosed using electrocardiograms (ECG). Except for a control group that received placebo, patients were provided with antihypertensive therapy.

During an almost five-year follow-up period, findings showed sudden cardiac death occurred in 17 black patients and 161 non-black patients. After researchers adjusted for factors such as age, sex, body mass index (a measure of body fat based on height and weight), and medical history of diabetes and heart disease, scientists found that black hypertensives had a 98 percent greater risk of SCD than non-black hypertensives.

“Black patients may be at a higher risk of SCD, but not because of other more well-known risk factors [such as coronary artery disease and previous heart attack],” said Peter M. Okin, MD, a director of the division of cardiology at Weill Cornell Medical College, and lead study author.

In general, researchers concluded that while the study found an association between sudden cardiac death and hypertension, additional studies are needed to prove a cause-and-effect relationship. What’s more, scientists believe more research is needed to explore the genetic, structural and functional differences that may put black hypertensives at greater risk for sudden cardiac death.

Out of the nearly 300,000 cases of SCD each year in the United States, researchers observed greater incidence of SCD among African Americans. Previously, this racial disparity in cases of SCD was partially explained by greater levels of hypertension in the African-American community. But no in-depth study evaluating SCD risk among different-race hypertensives has been conducted.

Click here to learn more about how high blood pressure can be controlled by lowering your salt and alcohol intake and exercising regularly.