心律失常总论课件

1、心律失常总论心律失常总论OutlineArrhythmia is any of a group of conditions in which the electrical activity of the heart is irregular or is faster or slower than normal. The heartbeat may be too fast (over 100 beats per minute) or too slow (less than 60 beats per minute), and may be regular or irregular. A heart

2、 beat that is too fast is called tachycardia and a heart beat that is too slow is called bradycardia. Although many arrhythmias are not life-threatening, some can cause cardiac arrest.四川大学华西医院22022/10/4OutlineArrhythmia is any of a DefinitionThe Origin, Rate, Rhythm, Conduct velocity and sequence of

3、 heart activation are abnormally四川大学华西医院32022/10/4DefinitionThe Origin, Rate, RhArrythmia related CardioanatomyThe cardiac muscle majority is composed of the ordinary cardiac muscle textile fiber, the small part for the cardiac muscle textile fiber of special differentiation, latter composes the car

4、diac pacing-conduction system四川大学华西医院42022/10/4Arrythmia related CardioanatomCardiac Conduction SystemSAN Internodal pathways AVN His bundle L./R. bundle branch Purkinje fibers2022/10/4四川大学华西医院5Cardiac Conduction SystemSAN Pacing conduction system四川大学华西医院62022/10/4Pacing conduction system四川大学华西Patho

5、genesis and Inducement of Arrhythmia Some physical conditionPathological heart diseaseOther system disease Electrolyte disturbance and acid-base imbalancePhysical and chemical factors or toxicosis2022/10/4四川大学华西医院7Pathogenesis and Inducement oMechanism of ArrhythmiaAbnormal heart pulse formationSinu

6、s pulseEctopic pulseTriggered activityAbnormal heart pulse conductionReentryConduct block2022/10/4四川大学华西医院8Mechanism of ArrhythmiaAbnormaPhase 1快速复极初期：钾离子外流Phase 0 快速或上升钠离子内流入进入细胞进行除极Phase 2 平台期: 持续的钠离子内流和缓慢钙离子内流和钾离子外流Phase 3 快速复极末期: 钾离子外流Phase 4 静息期5 Phases心肌细胞的动作电位Phase 1Phase 0 Phase 2 PhaseAbnor

7、mal heart pulse formationAutomaticityTriggered activity触发机制后电位产生于动作电位的第3相（早期）或第4相（晚期）可触发心律失常2022/10/4四川大学华西医院10Abnormal heart pulse formationAutomaticity Heart cells other than those of the SA node depolarize faster than SA node cells, and take control as the cardiac pacemaker. Factors that enhance

8、automaticity include: SANS, PANS, CO2, O2, H+, stretch, hypokalemia and hypocalcaemia. Examples: Ectopic atrial tachycardia or multifocal tachycardia in patients with chronic lung disease OR ventricular ectopy after MI2022/10/4四川大学华西医院11Automaticity Heart cells otherTriggered activity is like a domi

9、no effect where the arrhythmia is due to the preceding beat. Delayed after-depolarizations arise during the resting phase of the last beat and may be the cause of digitalis-induced arrhythmias. Early after-depolarizations arise during the plateau phase or the repolarization phase of the last beat an

10、d may be the cause of torsades de pointes (ex. Quinidine induced)2022/10/4四川大学华西医院12Triggered activity is like a Abnormal heart pulse conduction:Reentry: most common四川大学华西医院132022/10/4Abnormal heart pulse conductioFast Conduction PathSlow RecoverySlow Conduction PathFast RecoveryReentry RequiresElec

11、trical ImpulseCardiac Conduction Tissue2 distinct pathways that come together at beginning and end to form a loop. A unidirectional block in one of those pathways. Slow conduction in the unblocked pathway. 2022/10/4四川大学华西医院14Fast Conduction PathSlow ConduFast Conduction PathSlow RecoverySlow Conduct

12、ion PathFast RecoveryThe “Re-Entry” Mechanism of Ectopic Beats & RhythmsElectrical ImpulseCardiac Conduction TissueTissues with these type of circuits may exist: in microscopic size in the SA node, AV node, or any type of heart tissue in a “macroscopic” structure such as an accessory pathway in WPW2

13、022/10/4四川大学华西医院15Fast Conduction PathSlow ConduFast Conduction PathSlow RecoverySlow Conduction PathFast RecoveryPremature Beat ImpulseCardiac Conduction Tissue1. An arrhythmia is triggered by a premature beat The beat cannot gain entry into the fast conducting pathway because of its long refractor

14、y period and therefore travels down the slow conducting pathway only Repolarizing Tissue (long refractory period)The “Re-Entry” Mechanism of Ectopic Beats & Rhythms2022/10/4四川大学华西医院16Fast Conduction PathSlow Condu3. The wave of excitation from the premature beat arrives at the distal end of the fast

15、 conducting pathway, which has now recovered and therefore travels retrogradely (backwards) up the fast pathway Fast Conduction PathSlow RecoverySlow Conduction PathFast RecoveryCardiac Conduction TissueThe “Re-Entry” Mechanism of Ectopic Beats & Rhythms2022/10/4四川大学华西医院173. The wave of excitation f

16、ro4. On arriving at the top of the fast pathway it finds the slow pathway has recovered and therefore the wave of excitation re-enters the pathway and continues in a circular movement. This creates the re-entry circuitFast Conduction PathSlow RecoverySlow Conduction PathFast RecoveryCardiac Conducti

17、on TissueThe “Re-Entry” Mechanism of Ectopic Beats & Rhythms2022/10/4四川大学华西医院184. On arriving at the top of Atrial Re-entry atrial tachycardia atrial fibrillation atrial flutterAtrio-Ventricular Re-entry Wolf Parkinson White supraventricular tachycardiaVentricular Re-entry ventricular tachycardiaAtr

18、io-Ventricular Nodal Re-entry supraventricular tachycardiaRe-entry Circuits as Ectopic Foci and Arrhythmia Generators2022/10/4四川大学华西医院19Atrial Re-entryAtrio-VentriculbRADYCARDIASA slow rhythm (less than 60 beats/min)May be caused by a slowed signal from the SAN, a pause in the normal activity of the

19、 SAN, or by blocking of the electrical impulse on its way from the atria to the ventricles (AV block or heart block)May also be present in the normally functioning heart of endurance athletes or other well-conditioned persons2022/10/4四川大学华西医院20bRADYCARDIASA slow rhythm (lesMECHANISM OF BRADYCARDIAS窦

20、房结自律性受损如因炎症、缺血、坏死或纤维化可致窦房结功能衰竭，起搏功能障碍，引起窦性心动过缓，窦性停搏传导阻滞SAN及A病变，可引起S-A阻滞等AVB是由于AVN或房室束的传导功能降低，SAN的兴奋激动不能如期向下传导而引起，可分为生理性和病理性两种病理性常见于风湿性心肌炎、白喉及其他感染、冠心病、洋地黄中毒等生理性多系迷走神经兴奋性过高四川大学华西医院212022/10/4MECHANISM OF BRADYCARDIAS窦房结自律Classification of ArrhythmiaAtrialJunctional arrhythmiaVentricularHeart blocksSud

21、den arrhythmic death syndromeArrhythmia may be classified by rate (normal sinus rhythm, tachycardia, bradycardia) or mechanism (automaticity, reentry, junctional, fibrillation).It is also appropriate to classify by site of origin:四川大学华西医院222022/10/4Classification of ArrhythmiaAtDiagnosis of Arrhythm

22、iaMedical HistoryPhysical ExaminationLaboratory Test四川大学华西医院232022/10/4Diagnosis of ArrhythmiaMedical四川大学华西医院242022/10/4四川大学华西医院242022/10/22022/10/4四川大学华西医院252022/10/2四川大学华西医院252022/10/4四川大学华西医院262022/10/2四川大学华西医院26ELECTROCARDIOGRAM“5” steps approach to arrhythmiasStep1: Is there a “QRS”Step2: Is th

23、ere a “P” Wave Step3: What is the relationship between the P waves and the QRS complexes? Step4: Calculate rateStep5: Miscellaneous2022/10/4四川大学华西医院27ELECTROCARDIOGRAM“5” steps appStep 1: Is there a “QRS” (No pulse)YESNOCHAOTIC FLAT LINEWIDENARROWPEAVFAsystoleVT2022/10/4四川大学华西医院28Step 1: Is there a

24、“QRS” (No Step 2: Is there a “P” WaveYESNOVARYCONSTANTMORPHOLOGYRATE220 to 350AFJUNCTIONALInvertedRR IntervalJUNCTIONALAtrial Flutter2022/10/4四川大学华西医院29Step 2: Is there a “P” WaveYES2022/10/4四川大学华西医院302022/10/2四川大学华西医院302022/10/4四川大学华西医院312022/10/2四川大学华西医院31Step 3: What is the relationship between t

25、he P waves and the QRS complexes?2022/10/4四川大学华西医院32Step 3: What is the relationsh 0.2Io AVBConstant ?YesIIo AVB type 2NoRR intervalYesIIIoAVBNoType1 IIoPR intervalPR intervalHEART BLOCKn“P” = n“QRS” ?NoYesConstant?2022/10/4四川大学华西医院33 0.2Io AVBConstant1st Degree block(AV Nodal Delay)2022/10/4四川大学华西医

26、院341st Degree block(AV Nodal Del2022/10/4四川大学华西医院352022/10/2四川大学华西医院352022/10/4四川大学华西医院362022/10/2四川大学华西医院36Event Monitors Holter monitoring: Document symptomatic and asymptomatic arrhythmias over 24-48 hours. Can also evaluate treatment effectiveness in a-fib, pacemaker effectiveness and identify s

27、ilent MIs. Trans-telephonic event recording: patient either wears monitor for several days or attaches it during symptomatic events and an ECG is recorded and transmitted for evaluation via telephone. Only 20% are positive, but still helpful.2022/10/4四川大学华西医院37Event Monitors Holter monitoriExercise

28、testing Symptoms only appear or worsen with exercise. Also used to evaluate medication effectiveness (esp. flecanide & propafenone) You can assess SA node function with exercise testing.Mobitz 1 (Wenkebach) is blockage at the AV node, so catecholamines from exercise actually help! Mobitz 2 is blocka

29、ge at bundle of His, so it worsens as catecholamines from exercise increase AV node conduction, thus prognosis is worse.*PVCs occur in 10% without and 60% of patients with CAD. *PVCs DO NOT predict severity of CAD (neither for nor against)! 2022/10/4四川大学华西医院38Exercise testing Symptoms onlySignal Ave

30、raged ECGUsed only in people post MI to evaluate risk for v-fib or v-tach. Damage around the infarct is variable, so this measures late potentials (low-signal, delayed action potentials) as they pass through damaged areas. Positive predictive value is 25%-50% but negative predictive value is 90%-95%

31、, thus if test is negative, patient is at low risk. 2022/10/4四川大学华西医院39Signal Averaged ECGUsed only iElectrophysiologic Testing Catheters are placed in RA, AV node, Bundle of HIS, right ventricle, and coronary sinus (to monitor LA and LV). Used to evaluate cardiogenic syncope of unknown origin, symp

32、tomatic SVT, symptomatic WPW, and sustained v-tach. *Ablative therapy is beneficial in AV node reentry, WPW, atrial tachycardia, a-flutter, and some v-tach. Complication is 1%2022/10/4四川大学华西医院40Electrophysiologic Testing CaManagementPhysical maneuvers, Medications, Electricity conversion, or Electro

33、- or cryo-cautery.The method of cardiac rhythm management depends firstly on whether or not the affected person is stable or unstable四川大学华西医院412022/10/4ManagementPhysical maneuvers, Therapy PrincipalPathogenesis therapyStop the arrhythmia immediately if the hemodynamic was unstableIndividual therapy

34、2022/10/4四川大学华西医院42Therapy PrincipalPathogenesis Physical maneuvers(vagal maneuvers)A number of physical acts can increase parasympathetic nervous supply to the heart, resulting in blocking of electrical conduction through the AV node. This can slow down or stop a number of arrhythmias that originat

35、e above or at the AV node四川大学华西医院432022/10/4Physical maneuvers(vagal maneAnti-arrhythmia AgentsAnti-tachycardia agentsAnti-bradycardia agents2022/10/4四川大学华西医院44Anti-arrhythmia AgentsAnti-tacAnti-tachycardia agentsModified Vaugham Williams classificationI class: Natrium channel blockerII class: -rece

36、ptor blockerIII class: Potassium channel blockerIV class: Calcium channel blockerOthers: Adenosine, Digital2022/10/4四川大学华西医院45Anti-tachycardia agentsModifiePhase 1快速复极初期：钾离子外流Phase 0 快速或上升钠离子内流入进入细胞进行除极Phase 2 平台期: 持续的钠离子内流和缓慢钙离子内流和钾离子外流Phase 3 快速复极末期: 钾离子外流Phase 4 静息期5 Phases心肌细胞的动作电位Phase 1Phase 0

37、 Phase 2 PhaseClassification of AADs类别 亚 类 电 生 理 效 应 代 表 制 剂 新 制 剂 传导速度 不应期 Ap时限 a多奎尼丁Ajmaline、Pirmenol、Aprindinb/利多卡因Maxiletine、TocainidecEncainidePropafenone、Flecainide、Lorcainide、Ethmozide心得安=胺碘酮Sotabl异搏定硫氮唑酮Bepridi四川大学华西医院47其它药物包括： 洋地黄类(临床上称之为第五类)以及新斯的明、甲氧胺、氯化钾、硫酸镁、ATP等抗缓慢心律失常的药物，包括：拟交感胺类、阿托品类、碱

38、性药物等 2022/10/4Classification of AADs类别 亚 类 电Clinical usage: Ia classGuinidineProcainamideDisopyramide: Side effect: like M-cholinergic receptor blocker Less use in clinic 2022/10/4四川大学华西医院48Clinical usage: Ia classGuinidClinical usage: Ib classLidocaine MexiletinePerfect to ventricular tachyarrhythm

39、ia2022/10/4四川大学华西医院49Clinical usage: Ib classLidocaClinical usage: Ic classMoricizine PropafenoneCan be used in ventricular and/or supra-ventricular tachycardia and extrasystole.2022/10/4四川大学华西医院50Clinical usage: Ic classMoriciClinical usage: II classPropranolol: Non-selectiveMetoprolol: Selective 1-receptor blocker, Perfect to hypertension and coronary artery disease patients associated with tachyarrhythmia. -r