Case illustrations of long QT syndrome.

Abstract

Long QT syndrome (LQTS) is a rare potentially life-threatening condition. Physicians must remain vigilant and consider LQTS as a possible etiology in patients with a history of syncope. Prolongation of the QT interval on electrocardiogram (ECG) is an essential component for the diagnosis of LQTS, despite the limitations of this technique. Experience of analyzing the ECG and calculating corrected QTc still remain relevant and are the mainstay diagnostic tools. Often, the first sign of the problem is observed after careful evaluation of the resting ECG for the hallmark of the disorder. Unfortunately, more than 60% of physicians-even cardiologists-have been known to misinterpret the QT interval on ECG. The cases discussed in this article highlight the variable clinical presentation of prolonged QT interval and the need to be highly vigilant in clinical evaluation.