10:01am Sunday 20 August 2017

SUDDEN CARDIAC DEATH TWICE AS LIKELY IN Black patients with High Blood Pressure independent of other known risk factors

WASHINGTON – Black patients with high blood pressure, also known as hypertension, have a twofold risk of sudden cardiac death (SCD) regardless of other common risk factors such as age, gender, family history and pre-existing heart disease, according to the Losartan Intervention For Endpoint reduction (LIFE) in Hypertension study. The LIFE study, published in the April edition of HeartRhythm, the official journal of the Heart Rhythm Society, is the first study to show a direct correlation between race and the risk of SCD in hypertensive patients after adjusting for multiple factors[1].

In the United States, more than 250,000 deaths occur each year as a result of SCD. In fact, SCD claims one life every two minutes, taking more lives each year than breast cancer, lung cancer or AIDS.  In the general population, blacks appear to have a higher risk of SCD which has been attributed to the greater presence of risk factors specific to SCD.  However, researchers of the LIFE study examined the independent relationship between SCD and race to determine if black patients have a higher risk of SCD in hypertensive patients. 

The LIFE study enrolled a large population of 9,193 patients and examined 533 black and 8660 nonblack hypertensive patients with electrocardiographic (ECG) left ventricular hypertrophy (LVH). Single and multi-variable analyses were performed adjusting for racial differences in the prevalence of SCD risk factors and other prominent risk profiles. Study results show, during a mean follow-up of five years, SCD occurred in 178 patients: 17 blacks and 161 nonblack patients. The independent relationship of SCD to race was examined after adjusting for factors ranging from age, sex, body mass index, diabetes to history of heart disease. After adjusting for these factors, black patients had a 98 percent greater risk of SCD.

“The truly unique outcome of our study is the indication that black patients may be at a higher risk of SCD, but not because of other more well-known risk factors,” stated lead-author Peter M. Okin, MD, Professor of Medicine, Director of Clinical Affairs, Division of Cardiology, Weill Cornell Medical College and Attending Physician at New York-Presbyterian Hospital/Weill

Cornell Medical Center. “SCD remains a serious public health issue and it is our hope that the results of this study will help clinicians identify people at the highest risk for SCD in an attempt to reduce the likelihood of these fatal events from occurring.”

Evolving research has suggested that the increased rate of SCD in blacks may be in part attributable to an increased prevalence of mutations in the cardiac sodium channel gene SCN5A that may predispose them to the development of fatal and nonfatal ventricular arrhythmias.[25]  However, further studies and evidence are needed to better define genetic, structural and functional differences to better understand the increased incidence of SCD in black hypertensive patients. 

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About the Heart Rhythm Society

The Heart Rhythm Society is the international leader in science, education and advocacy for cardiac arrhythmia professionals and patients, and the primary information resource on heart rhythm disorders. Its mission is to improve the care of patients by promoting research, education and optimal health care policies and standards. Incorporated in 1979 and based in Washington, DC, it has a membership of more than 5,100 heart rhythm professionals in more than 72 countries around the world. www.hrsonline.org

 

 

1 Age, sex, body mass index, diabetes, history of heart failure, atrial fibrillation, myocardial infarction, ischemic heart disease, stroke, peripheral vascular disease, smoking, serum total and high-density lipoprotein cholesterol level, creatinine level, glucose level, and urine albumin/creatinine ratio and for incident myocardial infarction, in-treatment heart rate, QRS duration, diastolic and systolic pressure, Cornell voltage-duration product, and Sokolow-Lyon voltage left ventricular hypertrophy treated as time-varying covariates.

2 Splawski I, Timothy KW, Tateyama M, et al. Variant of SCN5A sodium channel implicated in risk of cardiac arrhythmia. Science 2002;297:1333-1336.

3 Ackerman MJ, Splawski I, Makielski JC, et al. Spectrum and prevalence of cardiac sodium channel variants among black, white, Asian, and Hispanic individuals: implications for arrhythmogenic susceptibility and Brugada/long QT syndrome. Heart Rhythm 2004; 1:600-607.

4 Burke A, Creighton W, Monte E, et al. Role of SCN5A Y1102 polymorphism in sudden cardiac death in blacks. Circulation 2005;112:798-802.

5Sun AY, Koontz JI, Shah SH, et al. The S1103Y cardiac sodium channel variant is associated with ICD events in African Americans with heart failure and reduced ejection fraction. Circ Cardiovasc Genet 2011;4:163-168.

 


[1] Age, sex, body mass index, diabetes, history of heart failure, atrial fibrillation, myocardial infarction, ischemic heart disease, stroke, peripheral vascular disease, smoking, serum total and high-density lipoprotein cholesterol level, creatinine level, glucose level, and urine albumin/creatinine ratio and for incident myocardial infarction, in-treatment heart rate, QRS duration, diastolic and systolic pressure, Cornell voltage-duration product, and Sokolow-Lyon voltage left ventricular hypertrophy treated as time-varying covariates.

[2] Splawski I, Timothy KW, Tateyama M, et al. Variant of SCN5A sodium channel implicated in risk of cardiac arrhythmia. Science 2002;297:1333-1336.

[3] Ackerman MJ, Splawski I, Makielski JC, et al. Spectrum and prevalence of cardiac sodium channel variants among black, white, Asian, and Hispanic individuals: implications for arrhythmogenic susceptibility and Brugada/long QT syndrome. Heart Rhythm 2004; 1:600-607.

[4] Burke A, Creighton W, Monte E, et al. Role of SCN5A Y1102 polymorphism in sudden cardiac death in blacks. Circulation 2005;112:798-802.

[5] Sun AY, Koontz JI, Shah SH, et al. The S1103Y cardiac sodium channel variant is associated with ICD events in African Americans with heart failure and reduced ejection fraction. Circ Cardiovasc Genet 2011;4:163-168.


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