[Congenital Cardiac Conduction Abnormalities]

Abnormalities in cardiac conduction can occur due to a variety of factors. So called "idiopathic", conduction system degeneration develops without evident causes and may have hereditary basis. In the majority of cases it has no clinical manifestation, do not require treatment and have overall good prognosis. In this review we focus on congenital complete atrioventricular block and progressive cardiac conduction defect - rare but malignant and potentially lethal conditions that can be caused by genetic mutations and may be isolated or associated with structural heart disease. Cardiac involvement is relatively common in rare hereditary diseases - myodystrophies and mitochondrial cytopathies. Conduction abnormalities are among the most severe manifestations that may determine prognosis in these rare genetic disorders. These conditions deserve special consideration because of rapid progression of conduction defects and high prevalence of sudden cardiac death if no appropriate treatment applied.