D2_电生理手术适应症及过程

1、电生理手术电生理手术适应症及过程适应症及过程n类型类型心动过缓心动过缓心动过速心动过速心动过缓心动过缓不能产生电刺激响应不能传导电信号 窦房结阻滞 病窦房室传导阻滞 (I 度, II 度e 传导阻滞和 III 度完全传导阻滞)束支传导阻滞心动过速心动过速异常自律病窦综合症特发性房速右室流出道室速特发性室速折返机制房颤典型房扑预激综合症隐性房室折返旁道房室结折返心动过速缺血性室速产生折返性心动过速的前提条件产生折返性心动过速的前提条件a 慢的旁道慢的旁道 b一个传导中断一个传导中断 (由于心肌细胞的恢复期由于心肌细胞的恢复期) c存在一个早搏存在一个早搏折返机制折返机制- slow pathwa

2、y- short refractory period- normal pathway- long refractory periodextrastimulusScenario 1局灶性心房早搏机理机理 : 起源于心房传导组织起源于心房传导组织在心动周期中较早的出现在心动周期中较早的出现心率不齐心率不齐 - 不正常的自率性搏动不正常的自率性搏动局灶性心房早搏机理机理 : 起源于心房内固定位置起源于心房内固定位置 心率心率: 心房心房 110 - 200/分钟分钟P 波波:形状依赖于起源点在心房的位置形状依赖于起源点在心房的位置QRS 复杂复杂:通常正常，有时会发生房室结处中通常正常，有时会发生房

3、室结处中断断心率不齐心率不齐 -不正常的自率性搏动不正常的自率性搏动心率不齐心率不齐 -不正常的自率性搏动不正常的自率性搏动- slow pathway- short refractory period- normal pathway- long refractory periodextrastimulusRe-entry activationScenario 2- slow pathway- short refractory period- normal pathway- long refractory periodextrastimulusScenario 3Premature Atria

4、l ContractionMechanism : Originates in the atrial conducting tissuesOccurs early in the cardiac cycleVT ECG Characteristics QRS complexes Wide and bizarre Ventricular rate 100 - 200 bpm P wave usually absent or obscured by the QRS complexes AV DissociationMechanism : Arise from an ectopic focus in t

5、he atriumRate : Atrial 110 - 200/minP wave : P wave morphology depends on the site of the ectopic focusQRS complex : usually normalEctopic Atrial Tachycardia心率不齐心率不齐 - 折返折返房颤房颤机理 : 早搏引发心房激动，在同一时间心房不同位置同时发生，使得心房的活动变的混乱。Atrial FibrillationMechanism : It is influenced by the functional and anatomic str

6、ucture of the right and left atrium. Related to a trigger extrastimulus which activates the atrium, that have existing conduction defects, and this results in chaotic activity in the atria. Atrial Rate : rapid, usually 400-600/minCharacterised by no discrete P waves, except fibrillating waves that g

7、ives rise to irregular, chaotic ECG baseline.Atrial Fibrillation-ECG Characteristics心率不齐心率不齐 - 折返折返Typical Atrial Flutter MechanismPropagation of impulses in a circular pathway usually around the tricuspid annulus - clockwise or counter-clockwise direction 心率不齐心率不齐 - 折返折返房扑房扑 机理:通常下是由于在三尖瓣环区域发生的环型折返

8、发出的等边的刺激信号引发。 “通常在 P波中会发现锯齿波的形态” 典型或是非典型Atrial Flutter - ECG Characteristics P wave morphology -“saw-tooth” flutter waves Atrial Rhythm/Rate - Regular/300bpm Counter-clockwise flutter - +ve flutter waves in V1, and ve V6 and inferior leads Clockwise flutter - +ve flutter waves in V6 and inferior lea

9、ds, and ve in V1心率不齐心率不齐 - 折返折返Wolff-Parkinson White (WPW) Syndrome Mechanism SR - conducts antegradely through the AV node and the accessory pathway Tachycardia - conducts antegradely via the accessory pathway and retrogradely through the AV node Pre-excitation of the ventricles (Delta wave)心率不齐心率不

10、齐 - 折返折返Wolff-Parkinson White (WPW) Syndrome Overt机理 : 在房室结附近有旁道有很典型的三角波）WPW ECG CharacteristicsPR Interval shortened, because of pre-excitationQRS widened, with slurring of the upstroke of the QRS complex known as DELTA WAVE心率不齐心率不齐 - 折返折返Atrioventricular Reentry Tachycardia (AVRT)Mechanism Conduct

11、s antegradely down the AV node-His-Purkinjie system, and conducts retrogradely to the atria via the accessory pathway心率不齐心率不齐 - 折返折返Atrioventricular Reentry Tachycardia (AVRT) 封闭型封闭型机理机理 : 在正向从在正向从AV node-His-蒲氏传导系统的蒲氏传导系统的传导途径之外还存在着反向传导的旁道传导途径之外还存在着反向传导的旁道AVRT ECG CharacteristicsRhythm Regular, tac

12、hycardia is paroxysmalQRS usually narrowP wave depends on where the pathway is locatedAVOrthodromicAVAntidromicAV Nodal Reentry Tachycardia (AVNRT)Mechanism : Reentry occurs at the AV node via 2 separate pathways : anterior (fast pathway) and posterior tracts (slow pathway) with different conduction

13、 velocities Impulse can conducts either via the slow pathway and then to the fast, or via the fast pathway and then to the slow心率不齐心率不齐 - 折返折返房室结折返性心动过速房室结折返性心动过速 (AVNRT)机理：机理： 在在 房室结上发生有前向快旁道和后向慢旁道房室结上发生有前向快旁道和后向慢旁道所构成的折返所构成的折返AVNRT - ECG CharacteristicsRate : 100 280 bpmP wave : Usually embedded w

14、ithin the QRS, or at the terminal end of the QRSAVSlowFastThe AV NodeArrhythmias - ReentryThe AV NodeVentricular TachycardiaMechanism Re-Entry - Usually related to the presence of substrate like scar tissues. Some electrically viable surviving muscle fibres exist within the scar, and provide for the re-entrant circuit Focal - Often related to enhanced