Eteiskammiojohtumishäiriöt

Eteiskammiojohtumishäiriöt, commonly known as atrioventricular (AV) conduction disorders, refer to a group of conditions where the electrical impulse traveling from the atria to the ventricles of the heart is slowed down or blocked. The AV node is the crucial junction responsible for this transmission.

These disorders are typically categorized by the degree of conduction disturbance. First-degree AV block is characterized by a prolonged PR interval on an electrocardiogram (ECG), indicating a delay in conduction without any dropped beats. Second-degree AV block involves intermittent failure of conduction, resulting in some atrial impulses not reaching the ventricles. This can manifest as either Mobitz type I (Wenckebach), where the PR interval progressively lengthens until a QRS complex is dropped, or Mobitz type II, where dropped beats occur unpredictably without preceding PR interval lengthening. Third-degree AV block, also known as complete heart block, represents a total failure of conduction from the atria to the ventricles. In this situation, the ventricles generate their own escape rhythm, which is often slow and unreliable.

The causes of eteiskammiojohtumishäiriöt are varied and can include underlying heart disease such as coronary artery disease, myocardial infarction, or cardiomyopathy. Inflammatory conditions like myocarditis, as well as certain medications (e.g., beta-blockers, calcium channel blockers, digoxin), can also impair AV conduction. Degenerative changes associated with aging are another common contributing factor.

Symptoms can range from asymptomatic to significant. Individuals with milder forms may experience no noticeable symptoms. However, more severe blocks can lead to dizziness, lightheadedness, fainting (syncope), shortness of breath, and fatigue due to the heart's reduced ability to pump blood effectively. Treatment depends on the type and severity of the block, as well as the presence of symptoms. In many cases, particularly with asymptomatic or mild first-degree block, no treatment is necessary. Symptomatic individuals or those with more advanced blocks may require medications to improve heart rate or the implantation of a pacemaker to ensure adequate ventricular pacing.