AtrioVentrikularKanaldefekt

Atrioventricular block, often abbreviated as AV block, refers to a condition where the electrical signals that trigger the heart's contractions are delayed or blocked as they travel from the atria to the ventricles. The atria are the two upper chambers of the heart, and the ventricles are the two lower chambers. The atrioventricular (AV) node is the specialized tissue responsible for conducting these electrical impulses. When this conduction is impaired, it can lead to a range of symptoms, from none to severe.

There are three main degrees of atrioventricular block. First-degree AV block is the mildest form, where the electrical signal is slowed down but still consistently reaches the ventricles. This often doesn't cause any noticeable symptoms. Second-degree AV block occurs when some electrical signals are blocked, meaning not every impulse from the atria makes it to the ventricles. This can lead to skipped beats and potentially dizziness or shortness of breath. There are two subtypes: Mobitz type I (Wenckebach) and Mobitz type II. Third-degree AV block, also known as complete heart block, is the most severe. In this case, no electrical signals from the atria reach the ventricles, and the ventricles generate their own slow, unreliable rhythm. This can cause significant symptoms like fainting, severe fatigue, and chest pain.

The causes of AV block can vary and include underlying heart disease, medications that affect heart rate, congenital heart defects, and age-related changes in the heart's electrical system. Diagnosis typically involves an electrocardiogram (ECG), which records the heart's electrical activity. Treatment depends on the type and severity of the block, as well as the presence of symptoms. For asymptomatic first-degree AV block, no treatment may be necessary. Symptomatic AV blocks, particularly second-degree Mobitz type II and third-degree block, often require the implantation of a pacemaker to regulate the heart's rhythm.