Saturday, April 21, 2012

Black hypertensive patients are at a significantly increased risk for sudden cardiac death (SCD)

The increased SCD risk in black patients was independent of their greater burden of risk factors for SCD and remained significant after adjusting for potential confounders including incident myocardial infarction and in-treatment blood pressure. The LIFE (Losartan Intervention for Endpoint Reduction) study examined the incidence of SCD in 533 black and 8660 non-black hypertensive patients with electrocardiographically determined left ventricular hypertrophy who were randomly allocated to receive treatment with either losartan 50 mg or atenolol 50 mg daily, both uptitrated as needed to achieve a target pressure of 140/90 mmHg or lower. The findings showed that during a mean follow-up period of 4.8 years, SCD occurred in 178 (1.9%) patients: 17 black and 161 non-black patients. The 5-year SCD rate was significantly higher in black patients than in nonblack patients, at 3.9% versus 1.9%. In univariate analysis, black hypertensive patients had a significant 97% higher risk for SCD than non-black patients. Multivariate analysis adjusting for potential confounders including history of heart failure, incident myocardial infarction, and diastolic and systolic blood pressure demonstrated that black race was significantly associated with a significant 98% increased risk for SCD. The increased rate of SCD in black hypertensive patients may be due to an increased prevalence of mutations in the cardiac sodium channel gene SCN5A, which could predispose them to developing fatal and nonfatal ventricular arrhythmias.

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