Atrioventricular block (AV block) (synonym: atrioventricular block; ICD-10-GM I44.3: other and unspecified atrioventricular block) is a cardiac arrhythmia that belongs to the group of conduction disorders.
AV block results in a delay in conduction of excitation between the atria and ventricles at the atrioventricular node (AV node; “atrioventricular node”) of the heart, which is interrupted temporarily or permanently.
The following degrees of AV block are distinguished depending on the extent of the disruption:
- 1st degree AV block
- 2nd degree AV block
- Mobitz type I (Wenckebach block)
- Mobitz type II (Mobitz block)
- AV block 3rd degree
Frequency peak: atrioventricular block occurs predominantly in older age (due to degenerative changes in the conduction system).
Course and prognosis: AV block often occurs as a concomitant of heart disease such as myocarditis (inflammatory disease of the heart muscle) and myocardial infarction (heart attack). In rare cases, AV block is congenital (congenital). If the forms of AV block are mild, these arrhythmias usually go unnoticed and no therapy is required. Severe forms cause bradycardia (heartbeat too slow: < 60 beats per minute) or bradyarrhythmias (heartbeat too slow and irregular). Associated with an unfavorable prognosis are Mobitz type II AV block and 3rd degree AV block. In these cases, as well as in cases of nonreversible (reversible) AV block and persistent (persisting) symptoms, placement of a permanent (durable) pacemaker is indicated.