Depolarization/repolarization, electrocardiographic abnormalities, and arrhythmias in cardiac channelopathies

Investigation of the etiology and pathogeneses of the genetic cardiac channelopathies has provided important insight into the mechanisms of ventricular arrhythmias. Some of these diseases are rare, such as the short QT-interval syndrome, but others such as the Brugada syndrome are the most common cause of unexplained sudden cardiac death in young men in Southeast Asia and Japan. Knowledge of the specific ion-channel defect causing the disease or syndrome is leading to pharmacological approaches that attempt to correct the ion transfer defects in channelopathies. The most clinically important challenge is to recognize which patients with the Brugada electrocardiogram who do not have a positive family history of this condition and do not have a history of syncope or aborted sudden death are at risk for arrhythmic death.