Why atrioventricular reentrant tachycardia?

Atrioventricular reentrant tachycardia may be caused by one-way block of one pathway, two conduction pathways, and excitation returning to the atrium.

1. One-way block of one pathway

has a one-way block pathway, and the other pathway has a relatively slow conduction velocity and a long refractory period. The excitation emitted by the sinus node cannot meet the refractory period and cannot conduct excitation. Excitation will be reversed, resulting in atrioventricular reentrant tachycardia.

2. Two conduction pathways

If there are two conduction pathways between the atria and ventricles, and the velocities and refractory periods are different, electrical signals will form reentrant between the two conduction pathways, and repeated cardiac electrical activity will be formed, causing atrioventricular reentrant tachycardia.

3.

Excitation returning from the sinus node to the bottom of the atrioventricular node along the original path will be transmitted back to the atrium, causing atrioventricular reentrant tachycardia.