rhythm basicsrhythm basics...objectivesobjectives • identify the components that make up the...

MODULE 1MODULE 1

Rhythm BasicsRhythm Basics

Module 1: Rhythm BasicsModule 1: Rhythm Basics

• The Conduction System– Impulse Formation– Impulse Conduction– Properties of Cardiac Function– 5 Phases of Action Potential

• Rhythm Disorders– Mechanisms– Arrhythmia Recognition

• Causes of Rhythm Disorders

• The Conduction System– Impulse Formation– Impulse Conduction– Properties of Cardiac Function– 5 Phases of Action Potential

• Rhythm Disorders– Mechanisms– Arrhythmia Recognition

• Causes of Rhythm Disorders

OverviewOverview

ObjectivesObjectives

• Identify the components that make up the electrical pathway known as the conduction system

• State the 5 phases of action potential• Describe the mechanisms causing rhythm

disorders

• Identify rhythm disorders on an EKG

• Identify the components that make up the electrical pathway known as the conduction system

• State the 5 phases of action potential• Describe the mechanisms causing rhythm

disorders

• Identify rhythm disorders on an EKG

Module 1: Rhythm BasicsModule 1: Rhythm Basics

THE CONDUCTION SYSTEMTHE CONDUCTION SYSTEM

Heart Beat AnatomyHeart Beat Anatomy

Sinus Node(SA Node)

• The Heart’s ‘Natural Pacemaker’

- 60-100 BPM at rest

SINUS NODE


AV NODE

Sinus Node(SA Node)

Atrioventricular Node (AV Node)

• Receives impulse from SA Node

• Delivers impulse to the His-Purkinje System

• 40-60 BPM if SA Node fails todeliver an impulse


BUNDLE OF HIS

Sinus Node(SA Node)


• Begins conduction to the Ventricles

• AV Junctional Tissue: 40-60 BPM

Bundle of His



Sinus Node(SA Node)

• Bundle Branches• Purkinje Fibers • Moves the impulse through

the ventricles for contraction

• Provides ‘Escape Rhythm’: 20-40 BPM

THE PURKINJE NETWORK

Bundle of His

Bundle Branches

Purkinje Fibers

Normal Sinus RhythmNormal Sinus Rhythm

Click heart to view animation

*Animation

Impulse Formation In SA NodeImpulse Formation In SA Node

Atrial DepolarizationAtrial Depolarization

Delay At AV NodeDelay At AV Node

Conduction Through Bundle BranchesConduction Through Bundle Branches

Conduction Through Purkinje FibersConduction Through Purkinje Fibers

Ventricular DepolarizationVentricular Depolarization

Plateau Phase of RepolarizationPlateau Phase of Repolarization

Final Rapid (Phase 3) RepolarizationFinal Rapid (Phase 3) Repolarization

Normal EKG ActivationNormal EKG Activation

Reading EKGsReading EKGs

Intervals and TimingIntervals and TimingNormal Ranges in Milliseconds:

• PR Interval 120 – 200 ms• QRS Complex 60 – 100 ms • QT Interval 360 – 440 ms

Normal Ranges in Milliseconds:

• PR Interval 120 – 200 ms• QRS Complex 60 – 100 ms • QT Interval 360 – 440 ms

Question?Question?

Where does the SA Node get its energy?Where does the SA Node get its energy?

AutomaticityAutomaticity

Cardiac Cells have

AUTOMATICITY!

Cardiac Cells have

AUTOMATICITY!


Cardiac CellsCardiac Cells

• Spontaneously depolarize• Generally present in:• Spontaneously depolarize• Generally present in:

• Upper (SA Node)- 60-100 BPM

• Upper (SA Node)- 60-100 BPM

• Middle (AV Junction)- 40-60 BPM

• Middle (AV Junction)- 40-60 BPM

• Lower (Purkinje Network)- 20–40 BPM

• Lower (Purkinje Network)- 20–40 BPM


Once a pacemaker cell initiates an impulse, its neighboring cells follow suit – like dominos!Once a pacemaker cell initiates an impulse, its neighboring cells follow suit – like dominos!

Question?Question?

What Triggers the First Cell?What Triggers the First Cell?

Action Potential of a Cardiac CellAction Potential of a Cardiac Cell

5 Phases5 Phases

Action Potential of a Cardiac Cell Action Potential of a Cardiac Cell

• Phase 0– Rapid or upstroke

depolarization with an influx of sodium ions into the cell

• Phase 0– Rapid or upstroke


5 Phases5 Phases

Action Potential of a Cardiac Cell Action Potential of a Cardiac Cell

• Phase 1– Early rapid repolarization

with transient outward movement of potassium ions


with transient outward movement of potassium ions

• Phase 0– Rapid upstroke




5 Phases5 Phases


with transient onward movement of potassium ions







• Phase 2 – Plateau Phase: Continued

Influx of Sodium & slow Influx of Calcium



5 Phases5 Phases















• Phase 3 – Repolarization:

Potassium outflow


Potassium outflow

5 Phases5 Phases














Potassium outflow


Potassium outflow

5 Phases5 Phases


• Phase 4 – Resting Phase

• Phase 4 – Resting Phase


Refractory PeriodsRefractory Periods

• ERP - Effective Refractory Period –Phases 0, 1, 2 and early Phase 3–A depolarization cannot be initiated by an impulse of any strength

• ERP - Effective Refractory Period –Phases 0, 1, 2 and early Phase 3–A depolarization cannot be initiated by an impulse of any strength


Refractory PeriodsRefractory Periods

• RRP - Relative Refractory Period–Late Phase 3 and early Phase 4

–A strong impulse can cause depolarization, possibly with aberrancy

• RRP - Relative Refractory Period–Late Phase 3 and early Phase 4

–A strong impulse can cause depolarization, possibly with aberrancy


Effective & Relative Refractory PeriodsEffective & Relative Refractory Periods

Question?Question?

Now that we understand impulse formation and normal heart function, let’s think…

What can possibly go wrong?

Now that we understand impulse formation and normal heart function, let’s think…

What can possibly go wrong?

RHYTHM DISORDERSRHYTHM DISORDERS

Rhythm DisordersRhythm Disorders

2 Categories of Rhythm Disorders2 Categories of Rhythm Disorders

Impulse FormationImpulse FormationDisorders ofDisorders of

Impulse ConductionImpulse Conduction

Underlying MechanismsUnderlying Mechanisms

Rhythm DisordersRhythm Disorders

Impulse FormationImpulse Formation • Abnormal Automaticity• Abnormal Automaticity


Mechanisms of Rhythm DisordersMechanisms of Rhythm Disorders

Abnormal AutomaticityAbnormal Automaticity

Abnormally Slow = Bradycardia• Failure due to disease

Excessively Rapid = Tachycardia• Due to sympathetic nervous system

Abnormally Slow = Bradycardia• Failure due to disease

Excessively Rapid = Tachycardia• Due to sympathetic nervous system



• Triggered Activity• Triggered Activity



Triggered ActivityTriggered Activity

• Afterpotentials occurring in Phase 3 (early) or 4 (late) of action potential

• Can trigger arrhythmias

• Afterpotentials occurring in Phase 3 (early) or 4 (late) of action potential

• Can trigger arrhythmias


Triggered ActivityTriggered Activity

Early Afterdepolarization • Potential Causes:

- Low potassium blood levels- Slow heart rate- Drug toxicity (ex. Quinidinecausing Torsades de Pointes)

Early Afterdepolarization • Potential Causes:

- Low potassium blood levels- Slow heart rate- Drug toxicity (ex. Quinidinecausing Torsades de Pointes)

Late Afterdepolarization• Potential Causes:

– Premature beats– Increased calcium blood

levels– Increased adrenaline

levels– Digitalis toxicity

Late Afterdepolarization• Potential Causes:

– Premature beats– Increased calcium blood

levels– Increased adrenaline

levels– Digitalis toxicity





Impulse ConductionImpulse Conduction • Slow or BlockedConduction

• Slow or BlockedConduction

Slowed or Blocked ConductionSlowed or Blocked Conduction


*Animation

• Impulse generated normally• Impulse slowed or blocked as it makes its way

through the conduction system

• Impulse generated normally• Impulse slowed or blocked as it makes its way

through the conduction system





Impulse ConductionImpulse Conduction • Slow or BlockedConduction

• Slow or BlockedConduction

• Reentry• Reentry


ReentryReentryConditions of ReentryConditions of Reentry


ReentryReentry

Substrate + Trigger = ReentrySubstrate + Trigger = Reentry


ReentryReentry

ReentryReentry

Identifying ReentryIdentifying Reentry

• Pace the heart at a rate faster than the known intrinsic tachycardia rate

• Stop the pacing• If the intrinsic rate resumes tachycardic,

then reentry is identified

• Pace the heart at a rate faster than the known intrinsic tachycardia rate

• Stop the pacing• If the intrinsic rate resumes tachycardic,

then reentry is identified


BradyarrhythmiasBradyarrhythmias

Bradyarrhythmia ClassificationsBradyarrhythmia Classifications

Classification Based on DisorderClassification Based on Disorder

Impulse FormationDisorders


BradycardiasBradycardiasImpulse Conduction

DisordersImpulse Conduction

Disorders





• Sinus Arrest• Sinus Arrest

Impulse ConductionDisorders


Sinus ArrestSinus Arrest

*Animation

• Failure of sinus node discharge

• Absence of atrial depolarization

• Periods of asystole

• Failure of sinus node discharge

• Absence of atrial depolarization

• Periods of asystole






• Sinus Bradycardia• Sinus Bradycardia



Sinus BradycardiaSinus Bradycardia

• Sinus Node emits energy very slowly• Sinus Node emits energy very slowly







• Brady/Tachy Syndrome• Brady/Tachy Syndrome



Brady/Tachy SyndromeBrady/Tachy Syndrome

• Intermittent episodes of slow and fast rates from the SA node or atria

• Brady <60 BPM • Tachy >100 BPM

• Intermittent episodes of slow and fast rates from the SA node or atria

• Brady <60 BPM • Tachy >100 BPM










• Exit Block• Exit Block

Exit BlockExit Block

• Transient block of impulses from the SA node• Identified by P-P interval relationship

• Transient block of impulses from the SA node

• Identified by P-P interval relationship











• 1st Degree AV Block• 1st Degree AV Block

First-Degree AV BlockFirst-Degree AV Block

• PR interval > 200 ms • Delayed conduction through the AV Node

- Example shows PR Interval = 320 ms

• PR interval > 200 ms • Delayed conduction through the AV Node

- Example shows PR Interval = 320 ms












• 2nd Degree AV Block• 2nd Degree AV Block

• Progressive prolongation of the PR interval until there is failure to conduct and a ventricular beat is dropped

• Progressive prolongation of the PR interval until there is failure to conduct and a ventricular beat is dropped

Known as Wenckebach BlockKnown as Wenckebach Block

Second-Degree AV Block - Mobitz ISecond-Degree AV Block - Mobitz I

*Animation

Second-Degree AV Block – Mobitz IISecond-Degree AV Block – Mobitz II

• Regularly dropped ventricular beats– Ex: 2:1 block (2 P-waves to 1 QRS complex)– Atrial rate = 75 BPM– Ventricular rate = 42 BPM

• Regularly dropped ventricular beats– Ex: 2:1 block (2 P-waves to 1 QRS complex)– Atrial rate = 75 BPM– Ventricular rate = 42 BPM













• 3rd Degree AV Block• 3rd Degree AV Block

• No impulse conduction from the atria to the ventricles

– Ventricular rate = 37 BPM– Atrial rate = 130 BPM– PR interval = variable

• No impulse conduction from the atria to the ventricles

– Ventricular rate = 37 BPM– Atrial rate = 130 BPM– PR interval = variable

Third-Degree AV BlockThird-Degree AV Block

*Animation













• 3rd Degree AV Block• 3rd Degree AV Block

• Bi/Trifascicular Block• Bi/Trifascicular Block

Bifascicular BlockBifascicular Block

• A complete or incomplete block in at least two conduction system pathways below the AV Node

• Marked by a widened QRS

• A complete or incomplete block in at least two conduction system pathways below the AV Node

• Marked by a widened QRS

Bifascicular BlockBifascicular Block

Right bundle branch block

and left anterior hemiblock

Right bundle branch block

and left anterior hemiblock

Right bundle branch block and

left posterior hemiblock

Right bundle branch block and

left posterior hemiblock

Complete left bundle branch

block

Complete left bundle branch

block

Trifascicular BlockTrifascicular Block

• Complete block in the right bundle branch, and• Complete or incomplete block in both divisions of the

left bundle branch • Identified by EP Study

• Complete block in the right bundle branch, and• Complete or incomplete block in both divisions of the

left bundle branch • Identified by EP Study


SummarySummary





• Sinus Arrest• Sinus Bradycardia• Brady/Tachy Syndrome

• Sinus Arrest • Exit Block• 1st Degree AV Block• 2nd Degree AV Block

-Mobitz I (Wenckebach Block)-Mobitz II

• 3rd Degree AV Block• Bi/Trifascicular Block

• Exit Block• Sinus Bradycardia• Brady/Tachy Syndrome

• 1st Degree AV Block• 2nd Degree AV Block

-Mobitz I (Wenckebach Block)-Mobitz II

• 3rd Degree AV Block• Bi/Trifascicular Block


TachyarrhythmiasTachyarrhythmias

• Paroxysmal– Ectopic focus, sudden onset, abrupt cessation

• Paroxysmal– Ectopic focus, sudden onset, abrupt cessation

• Sustained– Duration of > 30 seconds– Requires intervention to terminate

• Non-Sustained– At least 6 beats or < 30 seconds – Spontaneously terminates

• Recurrent– Occurs periodically– Periods of no tachycardia are longer than

periods of tachycardia

• Sustained– Duration of > 30 seconds– Requires intervention to terminate

• Non-Sustained– At least 6 beats or < 30 seconds – Spontaneously terminates

• Recurrent– Occurs periodically– Periods of no tachycardia are longer than

periods of tachycardia

Terms Describing TachycardiasTerms Describing Tachycardias

• Incessant– Long periods of tachy, short periods of NSR

• Incessant– Long periods of tachy, short periods of NSR

• Monomorphic– Single focus– Complexes are similar with equal intervals

• Polymorphic– Multiple foci– Complexes appear different with varied intervals

• SVT (Supraventricular Tachycardia)– Originating from above the ventricles

• Monomorphic– Single focus– Complexes are similar with equal intervals

• Polymorphic– Multiple foci– Complexes appear different with varied intervals

• SVT (Supraventricular Tachycardia)– Originating from above the ventricles

Terms Describing TachycardiasTerms Describing Tachycardias

Tachyarrhythmia ClassificationsTachyarrhythmia Classifications




TachycardiasTachycardiasImpulse Conduction

DisordersImpulse Conduction

Disorders




• Sinus Tachycardia• Sinus Tachycardia




Sinus TachycardiaSinus Tachycardia

• Origin: Sinus Node• Rate: 100-180 BPM• Mechanism: Abnormal (Hyper) Automaticity



• Sinus Tachycardia• Sinus Tachycardia• Atrial Tachycardia• Atrial Tachycardia





Atrial TachycardiaAtrial Tachycardia

• Origin: Atrium - Ectopic Focus• Rate: >100 BPM• Mechanism: Abnormal Automaticity





• Premature Contractions• Premature Contractions




Premature BeatsPremature Beats

Premature Atrial Contraction (PAC)Premature Atrial Contraction (PAC)

• Origin: Atrium (outside the Sinus Node)

• Mechanism: Abnormal Automaticity

• Characteristics: An abnormal P-wave occurring earlier than expected, followed by compensatory pause

• Origin: Atrium (outside the Sinus Node)


• Characteristics: An abnormal P-wave occurring earlier than expected, followed by compensatory pause

Premature Junctional ContractionPremature Junctional Contraction

• Origin: AV Node Junction


• Characteristics: A normally conducted complex with an absent p-wave, followed by a compensatory pause

• Origin: AV Node Junction


• Characteristics: A normally conducted complex with an absent p-wave, followed by a compensatory pause


Premature Ventricular Contractions (PVCs)Premature Ventricular Contractions (PVCs)

• Origin: Ventricles


• Characteristics: A broad complex occurring earlier than expected, followed by a compensatory pause

• Origin: Ventricles


• Characteristics: A broad complex occurring earlier than expected, followed by a compensatory pause


PVC PatternsPVC Patterns

•Bigeminy- Every other beat

•Trigeminy- Every third beat

•Quadrigeminy- Every fourth beat

•Bigeminy- Every other beat

•Trigeminy- Every third beat

•Quadrigeminy- Every fourth beat

Multifocal PVCMultifocal PVC

• Origin: Varies within the Ventricle


• Characteristics: Each premature beat changes axis; implies a different focus origin for each beat

• Origin: Varies within the Ventricle


• Characteristics: Each premature beat changes axis; implies a different focus origin for each beat







• Accelerated Idio-Junctional Rhythm




Accelerated Idio-Junctional RhythmAccelerated Idio-Junctional Rhythm

• Origin: AV Node or Junctional Tissue


• Characteristics: Occurs when cells depolarize at a rate faster than the Sinus Node

• Origin: AV Node or Junctional Tissue


• Characteristics: Occurs when cells depolarize at a rate faster than the Sinus Node









• Accelerated Idioventricular Rhythm (AIVR)




Accelerated Idioventricular RhythmAccelerated Idioventricular Rhythm

• Origin: Ventricle


• Rate: Ventricular rate >sinus rate, but <VT

• Characteristic: Dominates and takes over the rhythm



• Rate: Ventricular rate >sinus rate, but <VT

• Characteristic: Dominates and takes over the rhythm

Accelerated Idioventricular RhythmAccelerated Idioventricular Rhythm

Sinus Rhythm being taken over by an Idioventricular Rhythm

Sinus Rhythm being taken over by an Idioventricular Rhythm













• Atrial Flutter• Atrial Flutter

Atrial FlutterAtrial Flutter

• Origin: Right & Left Atrium

• Mechanism: Reentry

• Characteristics: Rapid, regular p-waves

• Origin: Right & Left Atrium


• Characteristics: Rapid, regular p-waves

*Animation













• Atrial Flutter• Atrial Flutter• Atrial Fibrillation• Atrial Fibrillation

Atrial Fibrillation (AF)Atrial Fibrillation (AF)

• Origin: Right and/or left atrium

• Mechanism: Multiple wavelets of reentry

• Rate 400 BPM

• Characteristics: Random, chaotic rhythm;atria quiver; associated withirregular ventricular rhythm

• Origin: Right and/or left atrium

• Mechanism: Multiple wavelets of reentry

• Rate 400 BPM

• Characteristics: Random, chaotic rhythm;atria quiver; associated withirregular ventricular rhythm

*Animation

Atrial Fibrillation (AF)Atrial Fibrillation (AF)

AF MechanismAF Mechanism

Why AF begets AFWhy AF begets AF

• Frequent or long AF episodes may cause chronic or permanent AF by:– Producing progressively shorter refractory periods

allowing reentry waves to self-propagate & spread

• Frequent or long AF episodes may cause chronic or permanent AF by:– Producing progressively shorter refractory periods

allowing reentry waves to self-propagate & spread

Multifocal FiringMultifocal Firing

Other AF MechanismsOther AF Mechanisms

• Mechanism: Abnormal Automaticity (multi-sites)

• Characteristics: Many depolarization waves;

activation occurs asynchronously;not in rhythm with sinus node

• Mechanism: Abnormal Automaticity (multi-sites)

• Characteristics: Many depolarization waves;

activation occurs asynchronously;not in rhythm with sinus node

Other AF MechanismsOther AF Mechanisms

Single Focus FiringSingle Focus Firing

• Mechanism: Abnormal Automaticity (single-focus, usually in the PosteriorLeft Atrium)

• Characteristics: Rapid discharge; single ectopic site

• Mechanism: Abnormal Automaticity (single-focus, usually in the PosteriorLeft Atrium)

• Characteristics: Rapid discharge; single ectopic site

Atrial Flutter vs. Atrial FibrillationAtrial Flutter vs. Atrial Fibrillation

Summary of Disease CharacteristicsSummary of Disease Characteristics

Atrial Flutter Atrial Flutter

Underlying MechanismUnderlying Mechanism

PatternPattern

Atrial Rate

Ventricular Rate

Rhythm

Atrial Rate

Ventricular Rate

Rhythm

Atrial FibrillationAtrial Fibrillation

• Multiple wavelet reentry• Multiple/single focus

firing

• Multiple wavelet reentry• Multiple/single focus

firing

• Wavy baseline• Wavy baseline

• 400 BPM

• Varies w/conduction

• Grossly Irregular

• 400 BPM


• Grossly Irregular

• Reentry via macro reentrant circuit

• Reentry via macro reentrant circuit

• Saw tooth baseline• Saw tooth baseline

• 250 to 400 BPM


• Usually regular

• 250 to 400 BPM


• Usually regular













• Atrial Flutter• Atrial Flutter• Atrial Fibrillation• Atrial Fibrillation• AVRT• AVRT

AVRTAVRT

• Extra pathway + AV Node = reentry • 2 Types

– Orthodromic• A to V through node, then enters accessory

pathway to loop• Produces narrow complex SVT

– Antidromic • A to V through accessory pathway, then

enters node to loop• Produces wide-complex SVT

• Extra pathway + AV Node = reentry • 2 Types

– Orthodromic• A to V through node, then enters accessory

pathway to loop• Produces narrow complex SVT

– Antidromic • A to V through accessory pathway, then

enters node to loop• Produces wide-complex SVT

• An SVT caused by the existence of an extrapathway from the atria to the ventricles

• An SVT caused by the existence of an extrapathway from the atria to the ventricles

OrthodromicOrthodromic


• Rate: 180 - 260 BPM, sometimes faster

• Characteristics: Extra electrical pathway to ventricles

Wolf-Parkinson-White (WPW) Syndrome is most common



• Characteristics: Extra electrical pathway to ventricles

Wolf-Parkinson-White (WPW) Syndrome is most common

AVRTAVRT

*Animation

AntidromicAntidromic



• Characteristics: Extra electrical pathway to ventriclesproduces wide complex tachycardia



• Characteristics: Extra electrical pathway to ventriclesproduces wide complex tachycardia

AVRTAVRT

*Animation

Wolff-Parkinson-WhiteWolff-Parkinson-White

• Accessory Pathway = Bundle of Kent • Orthodromic - 90%

- AV node – antegrade conduction; - Extra pathway – retrograde conduction

• Antidromic – 10% - Extra pathway – antegrade conduction- AV node – retrograde conduction

• Accessory Pathway = Bundle of Kent • Orthodromic - 90%

- AV node – antegrade conduction; - Extra pathway – retrograde conduction

• Antidromic – 10% - Extra pathway – antegrade conduction- AV node – retrograde conduction

Wolff-Parkinson-WhiteWolff-Parkinson-White

• Origin: Outside the AV Node


• Rate: 180-260 BPM – can be faster

• Characteristics: Short PR Interval (< 120 ms),wide QRS (> 110 ms), obvious delta wave

• Origin: Outside the AV Node


• Rate: 180-260 BPM – can be faster

• Characteristics: Short PR Interval (< 120 ms),wide QRS (> 110 ms), obvious delta wave













• Atrial Flutter• Atrial Flutter• Atrial Fibrillation• Atrial Fibrillation• AVRT• AVRT• AVNRT• AVNRT

AVNRTAVNRT

• Origin: AV Node


• Rate: 150 - 230 BPM, faster in teenagers

• Characteristics: Normal QRS with absent P-waves;most common SVT in adults

• Origin: AV Node


• Rate: 150 - 230 BPM, faster in teenagers

• Characteristics: Normal QRS with absent P-waves;most common SVT in adults

AVRT vs. AVNRTAVRT vs. AVNRT

AVRT• 180 – 260 BPM• Narrow QRS if orthodromic• Wide QRS if antidromic• Delta wave + in SR• PR < 120 ms• 1:1 Conduction

AVRT• 180 – 260 BPM• Narrow QRS if orthodromic• Wide QRS if antidromic• Delta wave + in SR• PR < 120 ms• 1:1 Conduction

AVNRT• 150 – 230 BPM• Narrow QRS • Short RP interval• No delta waves• Initiating PR long• P-waves buried in QRS• Conduction 1:1, or 2:1

when distal block present

AVNRT• 150 – 230 BPM• Narrow QRS • Short RP interval• No delta waves• Initiating PR long• P-waves buried in QRS• Conduction 1:1, or 2:1

when distal block present













• Atrial Flutter• Atrial Flutter• Atrial Fibrillation• Atrial Fibrillation• AVRT• AVRT• AVNRT• AVNRT• Ventricular Tachycardia• Ventricular Tachycardia

Ventricular ArrhythmiasVentricular Arrhythmias

Classification Based on MorphologyClassification Based on Morphology

• Monomorphic• MonomorphicVentricular Tachycardia (VT)

Ventricular Tachycardia (VT)

• Polymorphic• Polymorphic

• Origin: Ventricles (Single Focus)

• Mechanism: Reentry Initiated by abnormalAutomaticity or Triggered activity

• Characteristics: Rapid, wide, and regular QRS

• Origin: Ventricles (Single Focus)

• Mechanism: Reentry Initiated by abnormalAutomaticity or Triggered activity

• Characteristics: Rapid, wide, and regular QRS

EKG CharacteristicsEKG Characteristics

Monomorphic VTMonomorphic VT

*Animation

• Origin: Ventricles (Wandering Single Focus)

• Mechanism: Reentry with movement in the circuInitiated by Abnormal Automaticity oTriggered activity

• Characteristics: Wide and irregular QRS Complex thachanges in axis

• Origin: Ventricles (Wandering Single Focus)

• Mechanism: Reentry with movement in the circuiInitiated by Abnormal Automaticity oTriggered activity

• Characteristics: Wide and irregular QRS Complex thatchanges in axis

Polymorphic VTPolymorphic VT

*Animation

Torsades de PointesTorsades de Pointes


• Mechanism: Reentry (movement in focus)

• Rate: 200 – 250 BPM

• Characteristics: Associated with Long QT interval; QRS changes axis & morphology with alternating positive/negative complexes


• Mechanism: Reentry (movement in focus)

• Rate: 200 – 250 BPM

• Characteristics: Associated with Long QT interval; QRS changes axis & morphology with alternating positive/negative complexes


• Mechanism: Multiple Wavelets of reentry

• Characteristics: Irregular with no discrete QRS


• Mechanism: Multiple Wavelets of reentry

• Characteristics: Irregular with no discrete QRS

Ventricular Fibrillation (VF)Ventricular Fibrillation (VF)

*Animation


Common CausesCommon Causes

Causes of Rhythm DisordersCauses of Rhythm Disorders

Congenital• Present at birth due to genetics,

environment

Congenital• Present at birth due to genetics,

environment

Heart Disease• Myocardial Infarction, Cardiomyopathy,

High Blood Pressure

Heart Disease• Myocardial Infarction, Cardiomyopathy,

High Blood Pressure

Chemically Induced• Diet Pills, Cold Medicine, Illegal Drugs,

Caffeine, Tobacco, Alcohol

Chemically Induced• Diet Pills, Cold Medicine, Illegal Drugs,

Caffeine, Tobacco, Alcohol

Causes of Rhythm DisordersCauses of Rhythm Disorders

Secondary to other conditions• Hyper-Thyroid• Neurocardiogenic Syncope

- Hypersensitive Carotid Sinus Syndrome (CSS)- Vasovagal Syncope (VS)

Secondary to other conditions• Hyper-Thyroid• Neurocardiogenic Syncope

- Hypersensitive Carotid Sinus Syndrome (CSS)- Vasovagal Syncope (VS)

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