Long QT syndrome in African-Americans.

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 3456 Caucasians with a QTc > or = 450 ms from the U.S.

Influence of diabetes mellitus on outcome in patients over 40 years of age with the long QT syndrome.

Diabetes mellitus can affect ventricular repolarization, and we investigated the impact of diabetes on the risk for cardiac events in older patients with long QT syndrome (LQTS). The study population consisted of 1,152 patients with QTc interval >/=450 ms who were enrolled in the United States portion of the International Long QT Syndrome Registry and survived >40 years of age. Patients were categorized as having diabetes if they received oral diabetic medication or insulin.

Clinical implications for patients with long QT syndrome who experience a cardiac event during infancy.

Objectives: This study was designed to evaluate the clinical and prognostic aspects of long QT syndrome (LQTS)-related cardiac events that occur in the first year of life (infancy).

Background: The clinical implications for patients with long QT syndrome who experience cardiac events in infancy have not been studied previously.

Methods: The study population of 3,323 patients with QT interval corrected for heart rate (QTc) > or =450 ms enrolled in the International LQTS Registry involved 20 patients with sudden cardiac death (SCD), 16 patients with aborted cardiac arrest (ACA), 34 patients with syncope, and 3,253 patients who were asymptomatic during the first year of life.