医、技学院(华盛顿医疗手册培训-心律失常)课件

1、Cardiac ArrhythmiasJun JiangDepartment of CardiologyMechanisms of ArrhythmogenesisTACHYARRHYTHMIAS Definition Cardiac rhythms whose ventricular rate exceeds 100 beats per minute (bpm). Classification Narrow-Complex Tachyarrhythmia (QRS 100 b/m Causes: Withdrawal of vagul tone & Sympathetic stimu

2、lation (exercise, pain, or fight) Fever & inflammation Hypovolemia Anemai Hypoxia Heart Failure or Cardiogenic Shock (both represent hypoperfusion states) Heart Attack (myocardial infarction or extension of infarction) Drugs (alcohol, nicotine, caffeine) Therapy targeted at treatment of underlyi

3、ng pathophysiologic process Supraventricular Tachyarrhythmias Paroxysmal supraventricular tachycardi (PSVT) Prevalence and incidence of PSVT are 2.25 per 1,000 AVNRT (60%) AVRT (30%) Atrial fibrillation AF is the most common narrow-complex tachycardia seen in the inpatient setting Atrial flutter AFl

4、 can often accompany AF and is diagnosed one-tenth as often as AF but is twice as prevalent as the PSVTs Atrial tachycardia far less common Junctional tachycardia Sinoatrial nodal reentrant tachycardia (SANRT)TREATMENTAcute treatment of symptomatic SVT should follow the ACLS protocol as beforeAV nod

5、al blocking agents or techniques Many SVTs can be terminated AF, AFl, and some atrial tachycardias will persist with a slowing of the ventricular rateCorrection of electrolyte abnormalities (K+ and Mg+)Underlying etiologyChronic treatment should be aimed at either prevention of recurrence or prevent

6、ion of the complicationsRadiofrequency ablation (RFA) Success rates from 85% to 95% Compared to antiarrhythmic therapy, RFA improves quality of life and is more cost-effective in the long term15AVNRT Pin lead I, II, V1-V3AVRTWPW-A 4WPW-BAtrial Fibrillation Classification First occurrence. The sponta

7、neous conversion rate is 60% Paroxysmal AF : 7 days and usually 7 days in duration or require cardioversion Permanent AF Medical management Rate control of AF diltiazem, verapamil -adrenergic blockers digoxin Prevention of thromboembolic events Rhythm control Pharmacologic control Electrical cardiov

8、ersion Nonpharmacologic methods of rhythm control include catheter or surgical ablationClassification of Anti-arrhythmicsC l a ssA cti o nExa m p l esS i d e Effects1 AFa st so d ium chan nel bloc ker va ri esd ep o la riza ti o n a nd a ction p o tentiald ura ti o nQ uinidine,p ro ca ina m id e,d i

9、s op yra m id eC l a ss: na usea , vo m iti ngQ uinidine: hem o lyti ca nemi a, t hro m bo cy to pe nia ,ti nnitusProc aina mi d e: lup us1 BLido ca ine,M ex il etineLido ca ine: d izziness,co nfusi o n, seizures, co m aM ex il etine: trem o r, a taxi a,ras h1 CFl eca i nide,Prop afen o neFl eca i n

10、ide: p ro-a rrhythmi a ,na usea , dizzy ness2b eta-b lockers S A nod e & A V no d eco nd uctio nProp ra no l o l,m etop ro lolC l a ss: C H F, bro ncho spa sm ,b ra dy ca rd ia , hy po tension3Pro l o ng a cti o n p oten ti a l b y b lockingK+ cha nnelsA m i o d a ro ne,sota l o lA m i o d a ro

11、ne: hepa titi s,p ulm o na ry fi b rosi s, t hyroidd is o rde rs, p eriphe ralneu ropa thySo talol: b ro ncho sp a sm4calcium cha nnel bloc kers A V no d eco nd uctio nV era p a m il ,d ilit ia zemC l a ss: AV b lo ck,hyp o tensi o n, b ra d ycard i a,co nstipa ti o nStroke Risk in Patients With Non

12、valvular AF 23AF with WPWthere is no p wave, indicating that it did not originate anywhere in the atria, but since the QRS complex is still thin and normal looking, we can conclude that the beat originated somewhere near the AV junction. The beat is therefore called a junctional or a “nodal” beatJun

13、ctional Escape BeatQRS is slightly different but still narrow, indicating that conduction through the ventricle is relatively normalRecognizing and Naming Beats & RhythmsVentricular Tachyarrhythmias GENERAL PRINCIPLES Ventricular tachyarrhythmias should be initially approached with the assumptio

14、n that they will have a malignant course until proven otherwise Characterization of the arrhythmia involves hemodynamic stability Duration Morphology the presence or lack of underlying structural heart disease Ultimately, this characterization will aid in determining the patients risk for sudden car

15、diac arrest and need for device or ablation-based therapyDefinition of Ventricular TachyarrhythmiasNonsustained VT Three or more consecutive ventricular complexes (100 bpm) that terminates spontaneously within 30 seconds without significant hemodynamic consequences or need for interventionSustained

16、monomorphic VT Tachycardia composed of ventricular complexes of a single QRS morphology that lasts longer than 30 seconds or requires cardioversion due to hemodynamic compromise.Polymorphic VT is characterized by an ever-changing QRS morphology TdP is typically preceded by a prolonged QT interval in

17、 sinus rhythm Polymorphic VT is usually associated with hemodynamic collapse or instabilityVF is associated with disorganized mechanical contraction, hemodynamic collapse, and sudden deathSCD is defined as the death that occurs within 1 hour of the onset of symptoms In the United States, 350,000 cas

18、es of SCD occur annuallyEtiologyVT associated with structural heart disease Active ischemia or history of infarct Nonischemic cardiomyopathy Infiltrative cardiomyopathies (sarcoid, hemochromatosis, amyloid) Adults with prior repair of congenital heart disease Arrhythmogenic right ventricular dysplas

19、ia or cardiomyopathy Bundle branch reentry VTVT in the absence of structural heart disease Inherited ion channelopathies ( Brugada, long QT syndromes) Catecholaminergic polymorphic VT Idiopathic VT (VOT)Brugada criteria Recognizing and Naming Beats & RhythmsNotes on V-tach: Causes of V-tach Prio

20、r MI, CAD, dilated cardiomyopathy, or it may be idiopathic (no known cause) Typical V-tach patient MI with complications & extensive necrosis, EF40%, d wall motion, v-aneurysm)V-tach complexes are likely to be similar and the rhythm regular Irregular V-Tach rhythms may be due to to: breakthrough

21、 of atrial conduction atria may “capture” the entire beat beat an atrial beat may “merge” with an ectopic ventricular beat (fusion beat)Fusion beat - note p-wave in front of PVC and the PVC is narrower than the other PVCs this indicates the beat is a product of both the sinus node and an ectopic ven

22、tricular focusCapture beat - note that the complex is narrow enough to suggest normal ventricular conduction. This indicates that an atrial impulse has made it through and conduction through the ventricles is relatively normal.TREATMENTDifferentiation of SVT with aberrancy from VT on the basis of an

23、alysis of the surface ECG is critical in the determination of appropriate acute and chronic therapyImmediate unsynchronized DC cardioversion is the primary therapy for pulseless VT and VFNonpharmacologic therapy ICDs Radiofrequency catheter ablation Medications VF that is resistant to external defib

24、rillation requires the addition of IV antiarrhythmic agents. IV amiodarone appears to be more effective in increasing survival of VF when used in conjunction with defibrillation Chronic antiarrhythmic drug therapy is indicated for the treatment of recurrent symptomatic ventricular arrhythmiasLAORAOB

25、RADYARRHYTHMIAS Definition Cardiac rhythms whose ventricular rate 60 bpmCauses of BradycardiaIntrinsicCongenital disease Idiopathic degeneration(aging)Infarction or ischemiaCardiomyopathyInfiltrative disease: sarcoidosis, amyloidosisCollagen vascular diseasesSurgical traumaInfectious diseaseExtrinsi

26、cAutonomically mediated (Neurocardiogenic syncope Carotid sinus hypersensitivity) Increased vagal tone: coughing, vomiting, micturition, defecation, intubationDrugs: -blockers, calcium channel blockers, digoxin, antiarrhythmic agentsHypothyroidismHypothermiaNeurologic disorders: increased intracrani

27、al pressureElectrolyte imbalances: hyperkalemia, hypermagnesemiaHypercarbia/obstructive sleep apneaSepsisDIAGNOSISSTABLE: Is the patient hemodynamically unstable?SYMPTOMS: Does the patient have symptoms and do the symptoms correlate with the bradycardia?SHORT-TERM: Are the circumstances surrounding

28、the arrhythmia reversible or transient?SOURCE: Where in the conduction system is the dysfunction? Has the bradyarrhythmia been captured on electrocardiographic monitoring?SCHEDULE A PACEMAKER: Does the patient require a PPM? Sinus Bradycardia: HR 60 b/m Causes: Increased vagul tone, decreased sympathetic output, (endurance training) Hypothyroidism Heart Attack (common in inferior wall infarction) Vasovagul syncope (people passing out when they get their blood drawn) Depression Sick Sinus