Johtumishäiriöillä

Johtumishäiriöillä, also known as conduction disorders, refer to abnormalities in the electrical pathways of the heart that disrupt the normal sequence of electrical activation. These disorders can affect the speed or direction of electrical impulses, leading to irregular heart rhythms. The most common types of conduction disorders involve the sinoatrial (SA) node, the atrioventricular (AV) node, or the His-Purkinje system.

SA node dysfunction, also called sick sinus syndrome, occurs when the SA node, the heart's natural pacemaker, fails to generate electrical impulses at a normal rate or intermittently stops producing them. This can result in slow heart rates (bradycardia) or pauses in the heart's rhythm.

AV node block is another significant type of conduction disorder. The AV node is responsible for delaying the electrical impulse from the atria to the ventricles, allowing the atria to contract before the ventricles. AV block occurs when this signal transmission is slowed or completely interrupted. There are different degrees of AV block, from first-degree, where the delay is prolonged, to third-degree (complete heart block), where no impulses from the atria reach the ventricles, requiring the ventricles to generate their own slow escape rhythm.

Conduction abnormalities can also occur within the His-Purkinje system, which rapidly distributes electrical impulses to the ventricular muscle. Bundle branch blocks, such as right bundle branch block and left bundle branch block, are examples of these disorders, where one of the main pathways conducting electricity to the ventricles is impaired. This results in delayed ventricular activation.

The causes of conduction disorders are varied and can include age-related degeneration of the cardiac conduction system, underlying heart disease such as coronary artery disease or heart failure, inflammatory conditions, electrolyte imbalances, and certain medications. Symptoms can range from asymptomatic findings on an electrocardiogram to palpitations, dizziness, fainting (syncope), and shortness of breath, depending on the severity and type of the conduction defect. Diagnosis is typically made through electrocardiogram (ECG) and sometimes Holter monitoring. Treatment depends on the specific disorder and its severity and may involve medication or the implantation of a pacemaker.