Progressive cardiac conduction defect (PCCD) is a cardiac bundle branch disorder characterized by progressive alteration of cardiac conduction through the His-Purkinje system. It leads to complete atrioventricular block causing syncope and sudden death. Mutations in the SCN5A gene encoding the cardiac sodium channel are responsible for Brugada syndrome (BS) and also for PCCD. Furthermore, another PCCD is caused by mutations in TRPM4.
