Sympathetic stimulation and long QT syndrome type 1 (LQT1)

The inherited long QT syndrome (LQTS) is a common arrhythmia, which is associated with morbidity and mortality. Long QT syndrome type 1 (LQT1) is caused by mutations in KCNQ1 gene encoding the alpha subunit of slow component of the delayed rectifier K⁺ current (I_Ks) channel (Kv7.1), one of the main cardiac outward repolarizing K+ currents. The dysfunction of I_Ks channel, caused by mutations in KCNQ1, potentially produces prolongation of action potential duration (APD) in myocardial cells and QTc interval on ECG. Recent studies have confirmed that the occurrence of cardiac events in LQT1 are usually related to sympathetic stimulation (e.g., physical or emotional stress), especially swimming and diving. In the present review, we describe the relations between LQT1 and sympathetic stimulation. In addition, the present study summarizes relevant measures for prevention, diagnosis, and treatment of LQT1.