Etiology & Management of Long QT Syndrome

Long QT Syndrome (LQTS) is a congenital or acquired condition of the heart rhythm which is characterized on an electrocardiogram by a long QT interval and a type of ventricular tachycardia known as Torsades de Pointes (TdP). The pathophysiology of LQTS may be based in either increases in sympathetic activity in the electrical conduction system, or in abnormal ion flow within the heart, which lead to increases in action potential duration and subsequently prolongs the QT interval, causing predisposition to TdP. LQTS can result from inherited genetic mutations but can also be acquired due to medications such as Class I and Class III antiarrhythmics. Treatment for the condition includes beta-blocker medications, sympathetic denervation procedures, and cardioverter-defibrillator implants. LQTS is of particular interest due to its ability to lead to TdP, which can lead to unconsciousness or sudden cardiac death, and because of its typical onset and severity without other clinical signs which often leads to misdiagnosis. Work must be continued to investigate the drugs which can cause the acquired form of this disease, the genetics of the disease, and the best treatment for varying severities of the disease in order to improve patient outcomes.