Atrioventricular block

Atrioventricular block refers to the partial or complete, temporary or permanent blockade at the atrioventricular junction area due to physiological or pathological reasons when impulses discharged from the sinoatrial node are conducted from the atria to the ventricles. According to the degree of block, it can be divided into three degrees. First-degree block is characterized by prolonged atrioventricular conduction time, but all atrial impulses can still reach the ventricles; in second-degree block, some impulses fail to reach the ventricles; in third-degree block, all impulses fail to reach the ventricles, hence it is also called complete atrioventricular block.