Atrioventricular block is important

Atrioventricular block is medically known as atrioventricular conduction block. It is caused by abnormal conduction of electrical excitation between the atria and ventricles, resulting in abnormal heart rhythm, leading to abnormal normal function of the heart and pumping blood. Atrioventricular block is different from ordinary diseases. It is difficult for ordinary people to understand the situation, but because it is a heart problem, we are worried that there will be serious consequences. So, does atrioventricular block matter? Let’s take a look below.

Atrioventricular block

First-degree atrioventricular block is caused by the prolongation of the relative refractory period of a certain part of the atrioventricular conduction tissue, which causes a delay in atrioventricular conduction, but each atrial excitation can still be transmitted to the ventricles. It is occasionally seen in normal people with high vagus nerve tone or in elderly people without obvious heart disease. It is more common in rheumatic myocarditis, viral myocarditis, acute infection, atrioventricular septal defect, hypoxia, hyperkalemia, and the effects of drugs such as digitalis and quinidine. If the disease is multifunctional or the lesion is located at the atrioventricular node or proximal His bundle, it rarely causes clinical symptoms and has a better prognosis.

Severe second-degree type II and third-degree atrioventricular block can significantly slow the ventricular rate, accompanied by obvious symptoms such as syncope, loss of consciousness, and Adams-Stokes syndrome. Pacemaker implantation is required to avoid prolonged cardiac arrest, which can be life-threatening.

Pacemakers can be divided into single-chamber, dual-chamber, and triple-chamber pacemakers. For patients with atrioventricular block, if financial conditions permit, it is best to implant a dual-chamber pacemaker, which is closer to the normal function of the atria contracting first and the ventricles contracting later. But if financial difficulties arise, a single-chamber pacemaker can also save lives. If heart failure is present, implantation of a triple-chamber pacemaker may be considered.

Indications for permanent pacemaker implantation include:

1. Any level of high or complete atrioventricular block with clinical symptoms;

2. Bundle branch-branch block, intermittent second-degree type II atrioventricular block, and symptoms;

3. Sick sinus syndrome or atrioventricular block, ventricular rate often less than 50 beats/min, with obvious clinical symptoms, or intermittent ventricular rate less than 40 beats/min, or a 3s RR interval shown by dynamic electrocardiogram (the long interval can be relaxed to 5s in patients with atrial fibrillation), although asymptomatic, should also be considered;

4. Patients with sinus node dysfunction or (and) atrioventricular block who must use heart rate-slowing drugs due to other conditions should have a pacemaker implanted to ensure an appropriate ventricular rate.