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Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Cardiac Arrhythmias,Jun Jiang,Department of Cardiology,Mechanisms of Arrhythmogenesis,TACHYARRHYTHMIAS,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 stimulation (,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 underlying,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 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),TREATMENT,Acute treatment of symptomatic SVT should follow the ACLS protocol as before,AV nodal blocking agents or techniques,Many SVTs can be terminated,AF, AFl, and some atrial tachycardias will persist with a slowing of the ventricular rate,Correction of electrolyte abnormalities (K,+,and Mg,+,),Underlying etiology,Chronic treatment should be aimed at either prevention of recurrence or prevention of the complications,Radiofrequency 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 term,15,AVNRT,Pin lead I, II, V1-V3,AVRT,WPW-A,4,WPW-B,Atrial Fibrillation,Classification,First occurrence. The spontaneous 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 cardioversion,Nonpharmacologic methods of rhythm control include catheter or surgical ablation,Classification of Anti-arrhythmics,Stroke Risk in Patients With Nonvalvular AF,23,AF with WPW,there 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” beat,Junctional Escape Beat,QRS is slightly different but still narrow,indicating that conduction through the,ventricle is relatively normal,Recognizing and Naming Beats & Rhythms,Ventricular Tachyarrhythmias,GENERAL PRINCIPLES,Ventricular tachyarrhythmias should be initially approached with the assumption 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 cardiac arrest and need for device or ablation-based therapy,Definition of Ventricular Tachyarrhythmias,Nonsustained VT,Three or more consecutive ventricular complexes (100 bpm) that terminates spontaneously within,30,seconds without significant hemodynamic consequences or need for intervention,Sustained 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 sinus rhythm,Polymorphic VT is usually associated with hemodynamic collapse or instability,VF is associated with disorganized mechanical contraction, hemodynamic collapse, and sudden death,SCD is defined as the death that occurs within 1 hour of the onset of symptoms,In the United States, 350,000 cases of SCD occur annually,Etiology,VT 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 dysplasia or cardiomyopathy,Bundle branch reentry VT,VT 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 & Rhythms,Notes on V-tach,:,Causes of V-tach,Prior 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 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 ventricular focus,Capture 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.,TREATMENT,Differentiation of SVT with aberrancy from VT on the basis of analysis of the surface ECG is critical in the determination of appropriate acute and chronic therapy,Immediate unsynchronized DC cardioversion is the primary therapy for pulseless VT and VF,Nonpharmacologic therapy,ICDs,Radiofrequency catheter ablation,Medications,VF that is resistant to external defibrillation 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 arrhythmias,LAO,RAO,BRADYARRHYTHMIAS,Definition,Cardiac rhythms whose ventricular rate 60 bpm,Causes of Bradycardia,Intrinsic,Congenital disease,Idiopathic degeneration(aging),Infarction or ischemia,Cardiomyopathy,Infiltrative disease: sarcoidosis, amyloidosis,Collagen vascular diseases,Surgical trauma,Infectious disease,Extrinsic,Autonomically mediated (Neurocardiogenic syncope Carotid sinus hypersensitivity),Increased vagal tone: coughing, vomiting, micturition, defecation, intubation,Drugs:,-blockers, calcium channel blockers, digoxin, antiarrhythmic agents,Hypothyroidism,Hypothermia,Neurologic disorders: increased intracranial pressure,Electrolyte imbalances: hyperkalemia, hypermagnesemia,Hypercarbia/obstructive sleep apnea,Sepsis,DIAGNOSIS,STABLE: 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 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 Syndrome: Failure of the hearts pacemaking capabilities,Causes:,Idiopathic (no cause can be found),Cardiomyopathy (disease and malformation of the cardiac muscle),Implications and Associations,Associated with Tachycardia / Bradycardia arrhythmias,Is often followed by an,ectopic,“escape beat” or an,ectopic,“rhythm”,actually a retrograde p-wave may sometimes be seen on the right hand side of beats that originate in the ventricles, indicating that depolarization has spread back up through the atria from the ventricles,QRS is wide and much different (bizarre) looking than the normal beats. This indicates that the beat originated somewhere in the ventricles and consequently, conduction through the ventricles did not take place through normal pathways. It is therefore called a “ventricular” beat,Ventricular,Escape Beat,there is no p wave, indicating that the beat did not originate anywhere in the atria,Recognizing and Naming Beats & Rhythms,THANKS,
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