Cardiac channelopathies

Cardiac channelopathies are inherited cardiac disorders associated with potentially life-threatening ventricular arrhythmias. They are caused by genetic mutations of ion channels that alter cardiac cell membrane potential and intracellular haemostasis, and include long QT syndromes (LQTSs), Brugada syndrome and the much rarer catecholaminergic polymorphic ventricular tachycardia, idiopathic ventricular fibrillation, short QT syndrome and early repolarization syndrome. Presentation of these varies widely from sudden cardiac death to incidental diagnosis at the time of electrocardiography. While they are rare, diagnosis and subsequent familial screening can have significant results for both the index patient and family members. A clear understanding of the cardiac action potential helps to clarify the pathological mechanism of arrhythmogenesis that characterizes these conditions. Risk stratification of adverse outcomes from these conditions is complex and often imprecise. Medical therapy and implantable cardioverter-defibrillators have a potential role in patient management. It is recommended that complex decisions relating to these patients be discussed in a multidisciplinary team environment wherever possible. Most of this review focuses on LQTS and Brugada syndrome as these are the most common forms of cardiac channelopathies.