Blokkihäiriö

Blokkihäiriö, also known as heart block, refers to a condition where the electrical signals that control the heart's rhythm are interrupted or delayed as they travel from the atria to the ventricles. This disruption can lead to a slower or irregular heartbeat. The electrical impulse normally travels from the sinoatrial (SA) node, through the atrioventricular (AV) node, down the bundle of His, and into the Purkinje fibers, causing the heart muscle to contract in a coordinated manner.

There are different degrees of blokkihäiriö. First-degree AV block is characterized by a prolonged delay in the signal transmission through the AV node, but all impulses still reach the ventricles. This is often asymptomatic. Second-degree AV block involves some impulses failing to reach the ventricles, resulting in occasional dropped beats. This can be further classified into Mobitz type I (Wenckebach) and Mobitz type II. In Mobitz type I, the delay progressively lengthens until a beat is dropped. In Mobitz type II, the dropped beats are more unpredictable. Third-degree AV block, also known as complete heart block, occurs when no electrical impulses from the atria reach the ventricles. In this case, the ventricles generate their own slow, independent rhythm, leading to a significantly reduced heart rate.

Symptoms of blokkihäiriö can vary depending on the severity. Mild forms may cause no noticeable symptoms. However, more severe blocks can lead to dizziness, lightheadedness, fainting (syncope), shortness of breath, chest pain, and fatigue. The underlying causes of blokkihäiriö can include aging, heart disease such as coronary artery disease or heart attack, certain medications, electrolyte imbalances, and congenital heart defects. Diagnosis typically involves an electrocardiogram (ECG) to analyze the heart's electrical activity. Treatment depends on the type and severity of the block and may range from observation to the implantation of a pacemaker to regulate the heart rhythm.