In the Kardiologie differentiates one disturbances of the excitation formation from disturbances of the excitation line. As the name already says, excitation line interferences delays or interruptions of the electrical excitation of the heart musculature are. On forecourt level there are line interferences between the body-own master clock (sine knot) and the forecourt musculature. This disturbance is called sinuatrialer block (SA block). Over the forecourts the excitation spreads then vaguely. The Herzkammern are then again "“electrically isolated"” from the pre-chambers. Only a thin line course connects the forecourts with the chambers, the so-called AV-knot. Disturbances in this region are called AV-block. After the AV-knot the excitation is passed on over 2 line courses (Tawara thigh) on the musculature of the left and/or right Herzkammer. If one of these two thighs is interrupted, then one speaks of the link thigh block and/or right thigh block. If both thighs are interrupted, then that corresponds to the picture of a total AV-block.