Long QT Syndrome in African‐Americans

Abstract

Background We evaluated the risk factors and clinical course of Long QT syndrome (LQTS) in African-American patients. Methods The study involved 41 African-Americans and 3,456 Caucasians with a QTc ≥ 450 ms from the U.S. portion of the International LQTS Registry. Data included information about the medical history and clinical course of the LQTS patients with end points relating to the occurrence of syncope, aborted cardiac arrest, or LQTS- related sudden cardiac death from birth through age 40 years. The statistical analyses involved Kaplan-Meier time to event graphs and Cox regression models for multivariable risk factor evaluation. Results The QTc was 29ms longer in African-Americans than Caucasians. Multivarite Cox analyses with adjustment for decade of birth revealed that the cardiac event rate was similar in African-Americans and Caucasians with LQTS and that β-blockers were equally effective in reducing cardiac events in the two racial groups. Conclusions The clinical course of LQTS in African-Americans is similar to that of Caucasians with comparable risk factors and benefit from β-blocker therapy in the two racial groups.

Heart Disease and Stroke Statistics—2017 Update: A Report From the American Heart Association

“…38 LQTS has been reported among those of African descent, but its prevalence is not well assessed. 39 …”

Racial susceptibility for QT prolongation in acute drug overdoses

“…Specific factors that have been associated with an individual's baseline QT interval include the following: age (increased by 10 ms each decade), gender (females > males by 10 ms), race (Whites > Blacks by 5-10 ms), and genetic markers on chromosomes 7 and 11 (6-7). However, Blacks with Congenital Long QT Syndrome (LQTS) have significantly longer QTc than Whites without corresponding differences in cardiac event rates (8). Thus, it remains unclear if the factors which determine an individual's baseline QT interval (age, race, etc.)…”

Pharmacogenetics of Drug-Induced QT Interval Prolongation: An Update

“…A difference of 6–7 ms was demonstrated for Asian women in the normal range of the QT interval compared with other ethnicities, and this was a difference of 10 ms in the upper range of the QT interval [ 84 ]. Among 41 African Americans and 3456 Caucasians with a prolonged QT interval, African Americans had a 29-ms longer heart rate-corrected QT interval [ 85 ].…”