Cardiac channelopathies

Abstract

Cardiac channelopathies are inherited cardiac disorders associated with potentially life-threatening ventricular arrhythmias. These are caused by genetic mutations of ion channels that alter the cardiac cell membrane potential and intracellular haemostasis. They include long QT syndrome (LQTS), Brugada syndrome and the much rarer catecholaminergic polymorphic ventricular tachycardia, idiopathic ventricular fibrillation, short QT syndrome and early repolarization syndrome. The presentation of these disorders varies widely from sudden cardiac death to incidental diagnosis on electrocardiography. Although these conditions are rare, diagnosis and subsequent familial screening can have significant results for the index patient and their 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. Both medical therapy and implantable cardioverter–defibrillators have a potential role in managing these patients. These conditions are rare and it is recommended that the complex management decisions 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 channelopathy.