阵发性室上性心动过速(PSVT)可有三种常见的机理,即折返激动,自律性异常和触发激动之一引起。其中以折返激动最为常见。折返环路可涉及窦房结,心房或房室结,房室或结室旁路束(单独或联合存在)。折返之发生,必须有二条纵行分离,传导特性和不应期均不同的传导途径和一条与之相连结的末端途径所构成,一个适时冲动必须受阻于一条传导途径(逆向肢)而在另一条传导途径(前向肢)下传,如果冲动在前 Paroxysmal supraventricular tachycardia (PSVT) can have three common mechanisms, namely, reentry, autonomic abnormalities, and triggering one of the triggers. One of the most popular reentry. Retrocyclic circuits may involve sinoatrial node, atrial or atrioventricular node, atrioventricular or junctional shunt (either alone or in combination). Reentry occurs, there must be two longitudinal separation, conduction characteristics and refractory period are different from the conduction path and a link with the end of the way posed, a timely impulse must be blocked by a conductive pathway (reverse limb) and in another A pathway (forward limb) is down if the urge is on the front