Disturbed electrical conductance in any part of the electrical conductive system of the heart.

Causes for the appearance of a block can be temporary and transient or chronic and permanent.

The chronic condition is more frequent in old age.

The location of a block in the conductive system may be important for the clinical effect resulting thereof.

Blocks in some sites may be unnoticeable and are detected accidentally when ECG is recorded. On the other hand, blocks can cause significant slowing of the heart rate (Bradycardia), which is accompanied by symptoms.

Possible treatment modalities depend on the clinical manifestation, the duration of the disorder, its causative factor and its risk potential.