Electrocardiography&
Cardiac Arrhythmias
Saeed Oraii MD, Cardiologist
Interventional Electrophysiologist
Tehran Arrhythmia Clinic
Tehran Arrhythmia Center
Some slides have accompanied notes. To view them you can right
click on the screen, choose ‘Screen’ and then ‘Speaker Notes’.
Tehran Arrhythmia Center
ECG
A graphic recording of electrical potentials generated by the heart
A noninvasive, inexpensive and highly versatile test
Tehran Arrhythmia Center
Normal Pathway of Electrical Conduction
Tehran Arrhythmia Center
Cardiac Action Potential
Tehran Arrhythmia Center
Cardiac action potentials from different locations have different shapes
Tehran Arrhythmia Center
Electrophysiology
• Electric currents that spread through the heart are produced by three components– Cardiac pacemaker cells– Specialized conduction tissue– The heart muscle
• ECG only records the depolarization and repolarization potentials generated by atrial and ventricular myocardium.
Tehran Arrhythmia Center
Electrocardiograph 1903
Tehran Arrhythmia Center
Normal Electrocardiogram
ECG WaveformsLabeled alphabetically beginning with the P wave
Tehran Arrhythmia Center
Tehran Arrhythmia Center
QRS-T Cycle Corresponds to Different Phases of Ventricular
Action Potential
Tehran Arrhythmia Center
Limb Leads
Tehran Arrhythmia Center
Precordial Leads
Tehran Arrhythmia Center
Position of Precordial Electrodes
Tehran Arrhythmia Center
Precordial Leads
Tehran Arrhythmia Center
3-D Representation of Cardiac Electrical Activity
Tehran Arrhythmia Center
Timing Intervals
Tehran Arrhythmia Center
Vector Concept
• Cardiac depolarization and repolarization waves have direction and magnitude.
• They can, therefore, be represented by vectors.
• ECG records the complex spatial and temporal summation of electrical potentials from multiple myocardial fibers conducted to the surface of the body.
Tehran Arrhythmia Center
Limb Leads Directions
Tehran Arrhythmia Center
Vector Concept
Tehran Arrhythmia Center
Ventricular Depolarization
Tehran Arrhythmia Center
QRS Axis
Tehran Arrhythmia Center
Determination of QRS Axis
Tehran Arrhythmia Center
Direction of Propagation
Tehran Arrhythmia Center
Determination of QRS Axis
Tehran Arrhythmia Center
Determination of QRS Axis
Tehran Arrhythmia Center
Main Vector
Tehran Arrhythmia Center
Normal QRS Axis
Tehran Arrhythmia Center
Left Axis Deviation
Tehran Arrhythmia Center
Right Axis Deviation
Major ECG Abnormalities
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Right Atrial Enlargement
Tehran Arrhythmia Center
Left Atrial Enlargement
Tehran Arrhythmia Center
Left Ventricular Hypertrophy
Tehran Arrhythmia Center
Right Ventricular Hypertrophy
Tehran Arrhythmia Center
RVH, RA enlargement
Tehran Arrhythmia Center
Left Bundle Branch Block
Tehran Arrhythmia Center
Left Bundle Branch Block
Tehran Arrhythmia Center
Right Bundle Branch Block
Tehran Arrhythmia Center
RBBB
Tehran Arrhythmia Center
RBBB, RAD (Bifascicular Block)
Tehran Arrhythmia Center
RBBB, LAD (Bifascicular Block)
Tehran Arrhythmia Center
Myocardial Ischemia
• ECG is the cornerstone in the diagnosis of myocardial ischemia
• Findings depend on several factors:– Nature of the process, reversible vs. irreversible– Duration, acute vs. chronic– Extent, transmural vs. subendocardial– Localization, anterior vs. inferoposterior– Other underlying abnormalities
Tehran Arrhythmia Center
Acute Ischemia
Tehran Arrhythmia Center
Myocardial Infarction
Tehran Arrhythmia Center
Acute Pericarditis
Tehran Arrhythmia Center
Metabolic Abnormalities
Tehran Arrhythmia Center
Hyper-kalemia K 6.9
Tehran Arrhythmia Center
Same patient
K 3.9
Tehran Arrhythmia Center
Hypothermia, Osborn Wave
Tehran Arrhythmia Center
Hypothermia, Corrected
Tehran Arrhythmia Center
Right Axis Deviation
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Superior P Wave Axis
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Normal Sinus Rhythm
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Anterior MI
Tehran Arrhythmia Center
Tehran Arrhythmia Center
RBBB and Inferior MI
Tehran Arrhythmia Center
Tehran Arrhythmia Center
LA Enlargement and Prolonged PR Interval
Tehran Arrhythmia Center
Tehran Arrhythmia Center
LBBB
Tehran Arrhythmia Center
Tehran Arrhythmia Center
LA Enlargement and Prolonged PR Interval
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Left Anterior Hemiblock
Tehran Arrhythmia Center
Tehran Arrhythmia Center
LVH and LA Enlargement
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Anterior MI
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Old Inferior MI
Tehran Arrhythmia Center
Tehran Arrhythmia Center
RA Enlargement
Tehran Arrhythmia Center
Tehran Arrhythmia Center
RBBB, LAH, Prolonged PR (Trifascicular Block)
Tehran Arrhythmia Center
Tehran Arrhythmia Center
RBBB and Inferior MI
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Cardiac Arrhythmias
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Normal Pathway of Electrical Conduction
Tehran Arrhythmia Center
Normal Sinus Rhythm
• Normal and constant P wave contours
• Normal P wave axis
• Rate between 60 and 100 bpm
Tehran Arrhythmia Center
Normal Sinus Rhythm
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Anatomical Aspects of Normal Sinus Node
• Located at the superior anterolateral portion of right atrium near its border with the superior vena cava
• It is an epicardial structure near sulcus terminalis
• From endocardial approach the closest approach is near the superior end of crista terminalis
Tehran Arrhythmia Center
Sinus Node Function
• The dominant cardiac pacemaker
• Highly responsive to autonomic influences
• Decreasing rate with vagal stimulation
• Increasing rate with sympathetic activity
• Normal sinus rate under basal conditions is 60-100 bpm.
Tehran Arrhythmia Center
Sinus Tachycardia
• Sinus rhythm exceeding 100 bpm in adults
• Usually between 100 and 180 bpm but may be higher with extreme exertion
• Maximum heart arte decreases wit age from near 200 bpm to less than 140 bpm
• Gradual onset and termination
Tehran Arrhythmia Center
Sinus Tachycardia
Tehran Arrhythmia Center
Sinus TachycardiaCauses
• Common in infancy and childhood• Normal response to a variety of physiological and
pathological stresses– Exertion, anxiety
– Hypovolemia, anemia
– Fever
– Congestive heart failure
– Myocardial ischemia
– Thyrotoxicosis
• Drugs• Inflammation
Tehran Arrhythmia Center
Sinus Bradycardia
• Sinus rhythm at a rate less than 60 bpm
• Can result from excessive vagal or decreased sympathetic tone as well as anatomic changes in sinus node
• Frequently occurs in healthy young adults, particularly well-trained athletes
• Sinus arrhythmia often coexists
Tehran Arrhythmia Center
Sinus Bradycardia
Tehran Arrhythmia Center
Sinus Bradycardia Causes
• Hypothyroidism
• Drugs
• During vomiting or vasovagal syncope
• Increased intracranial pressure
• Hypoxia, hypothermia
• Infections
• Depression
• Jaundice
Tehran Arrhythmia Center
Sinus Arrhythmia
• Phasic variation in sinus cycle length
• Maximum minus minimum sinus cycle length exceeds 120 msec.
• May be considered the most common form of arrhythmia
• Respiratory form is a normal event
• Common in the young esp. with slower heart rates or enhanced vagal tone
Tehran Arrhythmia Center
Sinus Arrhythmia
Tehran Arrhythmia Center
Wandering Pacemaker
• Passive transfer of dominant pacemaker focus from sinus node to latent pacemakers in other atrial sites or AV junctional tissue
• Occurs in a gradual fashion over the duration of several beats
Tehran Arrhythmia Center
Wandering PacemakerECG
• A cyclical increase in RR interval
• A PR interval that gradually shortens to less than 120 msec
• A change in P wave contour that becomes negative in lead I or II or is lost within the QRS
Tehran Arrhythmia Center
Wandering Pacemaker
Tehran Arrhythmia Center
Inappropriate Sinus Tachycardia• Persistent sinus tachycardia at rest or with
minimal exertion• Usually occurs in otherwise healthy people• More common in health care personnel• May result from a defect in either
sympathetic or vagal nerve control of sinus node automaticity or an abnormality of intrinsic heart rate
• Some cases may need radiofrequency ablation of sinus node
Tehran Arrhythmia Center
Sinus Node Dysfunction Mechanisms
• A disease affecting a limited amount of tissue at or near the sinus node causing dysfunction of impulse formation or propagation or recovery from overdrive suppression
• A disease affecting the atria in general that consequently affects the sinus node function and also frequently generates atrial arrhythmias
Tehran Arrhythmia Center
Sinus Node DysfunctionECG Manifestations
• Sinus bradycardia
• Sinus pauses
• Sinus arrest
• Atrial asystole
• Sinus exit block
Tehran Arrhythmia Center
Sinus Pause
Tehran Arrhythmia Center
Sinoatrial Exit Block1st and 2nd degree
Tehran Arrhythmia Center
Sinus Node DysfunctionEtiology
• Most often in elderly as an isolated phenomenon
• Drugs
• Infiltration of atrial myocardium
• Interruption of blood supply
• Hypothyroidism, advanced liver disease, severe hypoxia, acidemia …
Tehran Arrhythmia Center
High Vagal Tone
• Usually in the young
• Normal heart rate response during exercise
• Normal intrinsic heart rate
• Bradycardia may be severe enough to cause syncope (especially in familial form)
Sick Sinus Syndrome•A combination of symptoms (dizziness,
fatigue, confusion, syncope and congestive heart failure) caused by sinus node dysfunction
•Atrial tachyarrhythmias may accompany sinus node dysfunction
<bradycardia-tachycardia syndrome>
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Sick Sinus Syndrome Clinical Manifestations
• Predominantly seen in the elderly
• Most patients with sinus node dysfunction are asymptomatic
• Two types of presentations– Syncope or near-syncope– Fatigue or worsening heart failure
Tehran Arrhythmia Center
Sick Sinus SyndromeDiagnosis
• Holter monitor recordings
• Intrinsic heart rate by autonomic blockade
• Sinus node recovery time
• Sinoatrial conduction time
The most important step is to correlate symptoms with ECG findings.
Tehran Arrhythmia Center
Normal SNRT
Tehran Arrhythmia Center
Abnormal SNRT
Tehran Arrhythmia Center
SA Block during Overdrive Pacing
Tehran Arrhythmia Center
Sinus Arrest after Termination of AF
Tehran Arrhythmia Center
Loop Recorder Showed Junctional Rhythm during Syncope
Tehran Arrhythmia Center
Sinus arrest with syncope
Tehran Arrhythmia Center
Therapy for Sick Sinus Syndrome
• Based mostly on symptoms and any clinical documentation of cardiac arrhythmia associated with these symptoms
• Drug therapy is rather limited
• Most effective treatment is pacing therapy
• Anticoagulation in certain situation
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Heart Block
• Disturbance of impulse conduction• Transient or permanent• Due to anatomical or functional impairment• Must be distinguished from interference, a
normal phenomenon that is a disturbance of impulse conduction caused by physiological refractoriness due to inexcitability from a preceding impulse
Tehran Arrhythmia Center
AV Conduction DisturbancesClinical Significance
• Heart block may be asymptomatic or lead to syncope or cardiac arrest
• Clinical significance of conduction abnormalities depend on:– The site of disturbance– The risk of progression to complete block– The probability that a subsidiary escape rhythm
distal to the site of block develops and is stable
Tehran Arrhythmia Center
AV BlockTypes
• First degree AV block
• Second degree AV block– Mobitz type I (Wenckebach)– Mobitz type II
• Third degree block (Complete heart block)
• High degree (advanced) AV block
Tehran Arrhythmia Center
First Degree AV Block
• Conduction time is prolonged but all impulses are conducted.
• PR interval exceeds 0.2 sec in adults
• Site of conduction delay may be in the AV node (most commonly), in the His-Purkinje system or both.
Tehran Arrhythmia Center
First Degree AV Block
Tehran Arrhythmia Center
Second Degree AV Block
• Block of some atrial impulses at a time when physiological interference is not involved
• Non-conducted P waves can be infrequent or frequent, at regular or irregular intervals, and can be preceded by fixed or lengthening PR intervals.
• The association of P with QRS is not random.
Tehran Arrhythmia Center
Mobitz Type I Second Degree AV Block
• Also called Wenckebach block
• Typical type characterized by progressive PR prolongation culminating in a non-conducted P wave
• Narrow QRS in most cases
Tehran Arrhythmia Center
WB
Tehran Arrhythmia Center
Wenckebach Block
Tehran Arrhythmia Center
Wenckebach Block
• Atypical pattern in over half the cases
• The site of block is almost always in the AV node.
• Generally benign and does not advance to more advanced AV block
• Can occur in normal children and well-trained athletes
Tehran Arrhythmia Center
Mobitz Type II Second Degree AV Block
• PR interval remains constant prior to the blocked P wave
• Commonly associated with bundle branch blocks
Tehran Arrhythmia Center
Mobitz Type II Second Degree AV Block
Tehran Arrhythmia Center
Mobitz Type II Second Degree AV Block
Tehran Arrhythmia Center
Mobitz Type II Second Degree AV Block
• Site of block His-Purkinje system in most case
• Often antedates the development of Adams-Stokes syncope and complete AV block
• Never observed in normal people
• An indication for implantation of permanent pacemaker even in asymptomatic cases
Tehran Arrhythmia Center
2:1 AV Block
Tehran Arrhythmia Center
2:1 AV Block
Tehran Arrhythmia Center
2:1 AV block
Tehran Arrhythmia Center
Complete AV block
• No atrial activity conducts to the ventricles• AV dissociation is present. The atria and
ventricles are controlled by independent pacemakers.
• Ventricular focus is usually located just below the site of block.
• Higher sites are more stable with a more faster escape rate.
Tehran Arrhythmia Center
Complete AV block
Tehran Arrhythmia Center
Complete AV blockIsorhythmic AV Dissociation
Tehran Arrhythmia Center
Advanced AV block
Block in two or more consecutive P waves
Tehran Arrhythmia Center
AV Conduction DisturbancesEtiology
• Degenerative diseases are the most common causes
• A variety of other diseases may be responsible: myocardial infarction, drugs, acute infections, infiltrative diseases, neoplasms, etc.
• Hypervagotonia
Tehran Arrhythmia Center
Investigation of the Site of AV Conduction Disease by
Electrophysiologic Study (EPS)
Tehran Arrhythmia Center
Cardiac Pacemakers
• The treatment of symptomatic bradyarrhythmias is implantation of cardiac pacemakers.
Tehran Arrhythmia Center
Cardiac Pacing
Tehran Arrhythmia Center
First Implanted Pacemaker
Tehran Arrhythmia Center
Common Uses for Permanent Pacemaker Therapy
Tehran Arrhythmia Center
AV Block With Carotid Massage
Tehran Arrhythmia Center
Long Asystole
Tehran Arrhythmia Center
Sinus Pauseand
Junctional Escape Beats
Tehran Arrhythmia Center
Sinus Pauseand Junctional Escape Beats
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Bradycardia- Tachycardia Syndrome
Tehran Arrhythmia Center
Mobitz Type I (Wenckebach)
Tehran Arrhythmia Center
2:1 AV block
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Complete Heart Block
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Sinus Pause
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Sinus Arrhythmia
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Sinus Tachycardia
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Wandering Pacemaker
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Sinus Tachycardia
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Wandering Pacemaker
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Asystole and Junctional Escape Rhythm
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Tachyarrhythmias
TachyarrhythmiasMechanisms
Automaticity
Tehran Arrhythmia Center
TachyarrhythmiasMechanisms
Triggered activity
Tehran Arrhythmia Center
TachyarrhythmiasMechanisms
Reentry
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Premature Complexes
Tehran Arrhythmia Center
Ventricular Premature Complexes
Compensatory Pause
Interpolated VPC
Tehran Arrhythmia Center
Premature Complexes
• The most common arrhythmias
• Detected during 24h Holter monitoring in over 60% of adults
• May cause palpitations or be asymptomatic
• May trigger more serious tachyarrhythmias
• May be associated with a normal heart or a variety of cardiac disturbances
Tehran Arrhythmia Center
Variability of Ventricular Ectopy with Age
• Effect of age on probability (%) ofhaving more than agiven number ofPVCs per 24 hoursin subjects withnormal hearts.
0%
10%
20%
30%
40%
50%
60% > 0 PVCs
> 50 PVCs
> 100 PVCs
10-29 30-39 40-49 50-59 60-69
Data from Kostis JB. Circulation. 1981;63(6):1353.
Age
Tehran Arrhythmia Center
Ventricular Premature Complexes
• Without heart disease, PVCs have not been shown to be associated with any increased incidence in morbidity or mortality
• In the presence of underlying disease (ischemia, heart failure …) they may add to the risk of the disease. No treatment is, however, shown to definitely decrease this increased risk.
Tehran Arrhythmia Center
Atrial Fibrillation
• The most common sustained arrhythmia
• Incidence increases progressively with age.
• Prevalence: 0.4% of overall population
• Mortality rate double that of control
• AF is characterized by disorganized atrial activity without discrete P waves
Tehran Arrhythmia Center
Atrial Fibrillation
Tehran Arrhythmia Center
Atrial Fibrillation
• Undulating baseline or atrial deflections of varying amplitude and frequency ranging from 350 to 600 bpm.
• Irregularly irregular ventricular response.
Tehran Arrhythmia Center
Atrial Fibrillation
• Morbidity related to:– Excessive ventricular rate– Pause following cessation of AF– Systemic embolization– Loss of atrial kick– Anxiety secondary to palpitations– Irregular ventricular rate
Tehran Arrhythmia Center
Atrial Fibrillation• Persistent AF usually in patients with
cardiovascular disease– Valvular heart disease
– Hypertensive heart disease
– Congenital heart disease
• Paroxysmal AF may occur with acute hypoxia, hypercapnia or metabolic or hemodynamic derangements
• Normal people with emotional stress or surgery or acute alcoholic intoxication
• Lone AF
Tehran Arrhythmia Center
Atrial Fibrillation
• Therapeutic Goals:– Control of ventricular rate– Restoration and maintenance of sinus rhythm– Prevention of thromboembolism
Tehran Arrhythmia Center
Atrial Flutter
• Regular atrial tachyarrhythmia with atrial rate between 250-350 bpm.
• Flutter waves are seen as saw-tooth like atrial activity
Tehran Arrhythmia Center
Atrial Flutter
• Atrial Flutter is a form of atrial reentry localized to right atrium.
• Typically the ventricular rate is half the atrial rate, but the ventricular response may be 4:1, 2:1, 1:1 etc.
Tehran Arrhythmia Center
Atrial Flutter Circuit
Tehran Arrhythmia Center
Atrial Flutter
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Atrial Flutter• Most often in patients with organic heart
disease
• Usually less long-lived than AF and may convert to AF.
• Control of ventricular rate is difficult in atrial flutter
• The most effective treatment is DC cardioversion
Tehran Arrhythmia Center
Paroxysmal Supraventricular Tachycardia (PSVT)
• Usually at a rate of 150-250 bpm
• No organic heart disease in the majority
• Presentations– Palpitations– Chest discomfort,dyspnea, lightheadedness– Frank syncope– SCD
Tehran Arrhythmia Center
PSVT
Tehran Arrhythmia Center
Tehran Arrhythmia Center
PSVT Mechanism
• Reentry in the vast majority
• Reentry may be localized to sinus node, atrium, AV junction or a macroreentrant circuit involving a bypass tract (WPW)
• In the absence of WPW, more than 90% are due to reentry through AV node or a concealed bypass tract
Tehran Arrhythmia Center
AV Nodal Reentrant Tachycardia(AVNRT)
• The most common form of paroxysmal supraventricular tachycardia (about 70%)
• More common in women (66%)• Usually a regular narrow QRS complex
tachycardia• No P wave is usually evident during the
tachycardia. Retrograde P waves may occasionally be seen at the end of QRS.
Tehran Arrhythmia Center
Longitudinal Dissociation Within AV Node
Slow Pathway
Fast Pathway
Atrium
His Bundle
Tehran Arrhythmia Center
AVNRT
Tehran Arrhythmia Center
AVNRT
Tehran Arrhythmia Center
Preexcitation
Tehran Arrhythmia Center
Wolff-Parkinson-White Syndrome
Tehran Arrhythmia Center
Tehran Arrhythmia Center
AV Reentrant Tachycardia(AVRT)
• Incorporates a bypass tract as part of the tachycardia circuit.
• Surface ECG:– Manifest with short PR interval and delta wave
(preexcitation)– Concealed with normal ECG
• Prevalence of ECG pattern: 0.1% to 0.3%.
Tehran Arrhythmia Center
AVRT
Tehran Arrhythmia Center
Concealed Accessory Pathway
Tehran Arrhythmia Center
Tehran Arrhythmia Center
PSVTTreatment
• Vagal maneuvers particularly carotid sinus massage
• AV nodal blocking drugs– Adenosine– Verapamil– Propranolol– Digoxin
• DC cardioversion if hypotensive
• Radiofrequency ablation
Tehran Arrhythmia Center
Electrophysiologic Study (EPS)
Tehran Arrhythmia Center
Catheter Positions at Fluoroscopy
Tehran Arrhythmia Center
Intracardiac Recordings
Tehran Arrhythmia Center
Radiofrequency Ablation (RFA)
Through femoral vein and right atrium
Tehran Arrhythmia Center
Loss of Delta during RF Burn
Tehran Arrhythmia Center
Tehran Arrhythmia Center
Loss of Delta during Burn
Tehran Arrhythmia Center
Ventricular ArrhythmiasDefinitions
• Premature Ventricular beats– Single beats– Ventricular Bigeminy, the appearance of one PVC after each sinus
beat– Couplets, two consecutive premature beats– Triplets, three consecutive premature beats– Salvos, runs of 3-10 premature beats
• Accelerated Idioventricular Rhythm (Slow VT), rate 60-100 bpm
• Ventricular Tachycardia (VT), rate over 100 bpm • Ventricular Flutter, regular large oscillations at a rate of
150-300 bpm• Ventricular Fibrillation (VF), irregular undulations of
varying contour and amplitude
Tehran Arrhythmia Center
Ventricular TachycardiaClassification
• Duration– Sustained VT defined as VT that persists for than 30 s
or requires termination because of hemodynamic collapse
– Nonsustained VT, 3 beats to 30 s
• Morphology– Monomorphic
– Polymorphic
Tehran Arrhythmia Center
Salvos
Tehran Arrhythmia Center
Sustained Monomorphic VT
Tehran Arrhythmia Center
Sustained Polymorphic VT
Tehran Arrhythmia Center
VT, Holter Recording
Tehran Arrhythmia Center
VTPresentations
Tehran Arrhythmia Center
VT Etiology
• VT generally accompanies some form of structural heart disease most commonly:– Ischemic heart disease– Cardiomyopathies
• Primary electrical abnormalities– Long QT syndromes– Brugada syndrome
• Idiopathic VT
Tehran Arrhythmia Center
Electrocardiographic Differentiation of VT vs. SVT with Aberrancy
• Clinical history
• AV dissociation
• QRS morphology
• QRS axis
• Fusion beat
• Capture beat
Tehran Arrhythmia Center
A-V Dissociation, Fusion, and Capture Beats in VT
Fisch C. Electrocardiography of Arrhythmias. 1990;134.
ECTOPY FUSION CAPTURE
V1 E F C
Tehran Arrhythmia Center
Fusion and Capture Beats in VT
Fisch C. Electrocardiography of Arrhythmias. 1990;135.
F C C
C C
Tehran Arrhythmia Center
VTPrognosis
• Depends on the underlying disease state– 75% first year mortality in the first few weeks
after MI– Poor prognosis in patients with left ventricular
dysfunction– No increased risk in those with idiopathic VT
Tehran Arrhythmia Center
Ventricular Fibrillation
Tehran Arrhythmia Center
Sudden Death Syndrome
• Incidence– 400,000 - 500,000/year in U.S.– Only 2% - 15% reach the
hospital– Half of these die before
discharge
• High recurrence rate
Tehran Arrhythmia Center
Underlying Arrhythmia of Sudden Death
VT62% Bradycardia
17%
Torsadesde Pointes
13%
PrimaryVF8%
Adapted from Bayés de Luna A. Am Heart J. 1989;117:151-159.
Tehran Arrhythmia CenterTehran Arrhythmia Center
Snapshot of Death
Tehran Arrhythmia CenterTehran Arrhythmia Center
Return of LifeNot the usual case !
Tehran Arrhythmia Center
Clinical Substrates Associated with VF Arrest
• Coronary artery disease• Idiopathic cardiomyopathy• Hypertrophic cardiomyopathy• Long QT syndrome• RV dysplasia• Rarely: WPW syndrome
Tehran Arrhythmia Center
VT/VFTherapeutic Options
• Antiarrhythmic drugs
• Anti-tachycardia pacing
• Radiofrequency ablation
• Implantable defibrillators
Tehran Arrhythmia Center
Earliest Defibrillator in Clinical Use, 1899
Tehran Arrhythmia Center
First Implantable Defibrillator 1970
Tehran Arrhythmia Center
Thoracotomy Lead System, the technique
used at the beginning
Tehran Arrhythmia Center
Nonthoracotomy Lead System
Tehran Arrhythmia Center
Pectoral ImplantationThe Current Technique
Tehran Arrhythmia Center
Tiered Therapy Defibrillators
Tehran Arrhythmia Center
Defibrillator Function
Tehran Arrhythmia Center
Interrogated ICD EventVT, treated appropriately by burst pacing therapy
Tehran Arrhythmia Center
Interrogated ICD EventVT (CL 320ms), no response to burst pacing therapy
Tehran Arrhythmia Center
Interrogated ICD EventVT (CL 320ms), cardioverted by DC shock
Tehran Arrhythmia Center
Clinical Uses of Defibrillator Therapy
Tehran Arrhythmia Center
Congenital Long QT Syndrome
A Frequently Missed Diagnosis
Tehran Arrhythmia Center
Long QT Interval
Tehran Arrhythmia Center
Long QT Interval
Tehran Arrhythmia Center
Long QT Interval
Tehran Arrhythmia Center
Clinical Manifestations
• Long QT syndrome is characterized by the presence of a long QT interval (usually over 440 ms) and emergence of ventricular arrhythmias.
• The presenting arrhythmia is a polymorphic ventricular tachycardia called ‘Torsade de Pointes’.
• Patient present with recurrent syncope or sudden cardiac death.
• Early diagnosis by ‘looking at ECG’ is critical!
Tehran Arrhythmia Center
Torsade de Pointes
• Prolonged QT interval associated with a polymorphic VT characterized by QRS complexes that change in amplitude and cycle length, giving the appearance of oscillations around the baseline
• Congenital or acquired
Tehran Arrhythmia Center
Brugada SyndromeDefinition
• Clinical-electrocardiographic diagnosis based on:
- High incidence of sudden cardiac death
- Structurally normal heart
- Characteristic ECG pattern
Tehran Arrhythmia Center
ECG Abnormalities
• ST segment elevation in V1-V3
• QRS complex resembling RBBB
• J-point elevation
Tehran Arrhythmia Center
Brugada ECG Pattern
Tehran Arrhythmia Center
Brugada ECG Pattern
Tehran Arrhythmia Center
History• First time in 1986: a 3-year polish boy• First presentation at NASPE meeting in
1991• First paper by Pedro and Josep Brugada in
1992• In the Philippines as “ bangungut”• In Japan as “Pokkuri”• In Thailand as “ Lai tai”, SUDS Circ. 1997
• Thai men correlated to Brugada, SUNDS Hum. Mol. Gen. 2002
Tehran Arrhythmia Center
Brugada Syndrome Prevalence in men (8:1 ratio males: females)
Familial incidence (autosomal dominant with incomplete penetrance ranging between 5 and 66 per 10 000)
True prevalence is difficult to estimate as the ECG pattern is often concealed.
It is endemic in Southeast Asia including: Thailand, Japan, Laos, Cambodia, Vietnam, the Philippines, and China.
Appearance of arrhythmic events at an average age of 40 years
Tehran Arrhythmia Center
Clinical ManifestationsSudden cardiac deathSyncope, seizure, agonal respiration, Episodes at night during sleep with labored
respiration, agitation, loss of urinary control, recent memory loss
Most commonly occurs during sleep, in particular during the early morning hours
Early diagnosis is of utmost importanceThe only treatment is currently implantation of an
‘Implantable Cardioverter Defibrillator’.