A. Electrophysiological basis of arrhythmias (2) Reentrant reexcitation(reentry) Circuits(especially in enlarged ventricles) Wolff-Parkinson-White syndrome) Unidirectional (one-way block (myocardial injury) Slow conduction ■ Heterogeneity in ERP
◼ (2) Reentrant reexcitation (reentry) ◼ Circuits (especially in enlarged ventricles) ◼ ( Wolff-Parkinson-White syndrome) ◼ Unidirectional (one-way) block ◼ (myocardial injury) ◼ Slow conduction ◼ Heterogeneity in ERP A. Electrophysiological basis of arrhythmias
A Normal mpule Ventricle wal B Unidirectional Block Impulse Impulse travels in retrograde direction and reenters the conduction pathway causing an extra or irregular heart beat
normal Unidirectional block Block
传导阻滞区 心室壁 A.正常传导过程 B.传导减慢并发生单向传导阻滞 传导阻滞区 传导阻滞区 C.传导阻滞区反向导通 D.折返形成 图25-3折返形成机制
房室旁路 图25-4折返与心室颤动 图255预激综合征中房室折返环路的形成 病理条件下,心室内存在多个折返 环路时,将发生心室颤动