Heart diseases congenital - fetal anomalies of development of heart (including its valves, septums) and large vessels. Their frequency not identical in different regions, on the average they are observed approximately at 7 of 100 alive newborns. In a small part of cases congenital defects have the genetic nature, as the basic reasons of their development consider exogenous influences on organs mainly in 1 trimester of pregnancy (virus, for example, a rubella, and other diseases of mother, an alcoholism, application of some medical products, influence of an ionizing radiation, etc.). All congenital defects can become complicated an infectious endocarditis with the advent of additional valval lesions.