SCN5a overlap syndromes. This episode: long QT syndrome type 3 meets multifocal ectopic Purkinje-related premature contractions.

The SCN5a gene encodes the ion-conducting subunit (Nav1.5) of the cardiac sodium channel. The main function of Nav1.5 is to enable a large and rapid, but transient, influx of sodium ions (INa) during the upstroke phase of the cardiac action potential. By doing so, Nav1.5 is responsible for the initiation of the cardiac action potential and thereby cardiac excitability. SCN5a mutations have been associated with inheritable syndromes, long QT syndrome type 3 (LQT3) in 1995, Brugada syndrome (BrS) in 1998, and several other diseases in the years thereafter, e.g., cardiac conduction disease, sick sinus syndrome, atrial fibrillation, multifocal ectopic Purkinje-related premature contractions (MEPPC; see further), and dilated cardiomyopathy.
Source: Heart Rhythm - Category: Cardiology Authors: Source Type: research