Basic Dysrhythmias

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Basic Dysrhythmias

• Chemeketa Paramedic Program
• -Basic Anatomy of the Heart
• -Electrical Conduction of the Heart
• -A System of Defining 3-Lead EKGs

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What is an

• EKG?
• ECG?
• EEG?
• EGG?
• Isnt School Great?

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Heart A P

• Location
• Pieces, Parts
• Important Vessels
• Electrolyte Role
• Pulling apart waveforms

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Valves Vessels
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Review of Important Vessels
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A System of Checks Balances

• Respond by
• Stimulating sympathetic
• Adrenergic response
• Alpha, Beta Dopaminergic
• Norepi Epi release
• Inhibiting Parasympathetic
• Acetylcholine
• Cholinergic Response
• Medulla
• Regulatory organ

• Baroreceptors (Pressoreceptors)
• Found
• Internal carotid arteries
• Aortic Arch
• Chemoreceptors
• Found in same places
• Monitors pH, O2 CO2

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Electrical Conduction System

• Sympathetic-Thoracic/Lumbar Nerve
• Norepinephrine
• HR, Contractility
• Parasympathetic-Vagus Nerve
• Acetylcholine
• HR (Valsalva)
• Chronotropic-HR
• Inotropic-Contraction

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Electrolytes Conduction

• Excitable cells of the Heart
• Self-depolarizing cells (Automaticity)
• Electrolytes of the Heart (Na / K/ Ca)

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Electrolytes Conduction

• Membrane Potential (MP)
• Slight difference between charge inside out
• Threshold
• MP becomes high enough to depolarize
• Action Potential
• Ability of cells at a given time
• Difference (mV) between inside out

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The Cardiac Cycle
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Membrane Potential
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Sodium-Potassium

• MP Rises
• Na Channels Open
• Rapid Influx (Fast Channels)
• Cell Attains Charge
• K Channels Open
• Outflow
• The Pump
• ATP Transports
• 3 Na out 2 K in
• Restores Resting cellular conditions

• Calcium
• Slow Channels
• Selective Permeability
• The Wave
• One cell contraction
• Spreads

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Electrical Conduction System

• Na in K out Depolarization
• K in Na out Repolarization
• Imbalances in K or Na
• Effects Automaticity Conduction
• Hypo hyperkalemia affects irritability
• Ca - Depolarization and Contraction
• Affects Contractility
• Hypo Hypercalcemia effects contractile force

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I know what youre thinkingWho gives a _at_ !!!

• You are caring for a patient with a rapid heart
  rate. You follow protocols and administer 20mg
  of Diltiazem.
• Youre patient responds by becoming
• Less responsive
• Bradycardic
• B/P drops to 72/40
• Weak Pulse at wrist
• Not responding to fluid, time or positioning.
• What now???
• Calcium Gluconate 10
• 500 1000 mg slow IV Push

_at_ Dang
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Phases

• Phase 0 Rapid Depolarization
• Reached max potential -90mV
• Fast Na Channels Open
• Cell now positive 25mV
• Phase 1 Early Rapid Repolarization
• Fast Na Channels Close
• K still being lost
• MP approaching 0mV
• Phase 2 Prolonged Slow Repolarization
• Plateau Phase
• Muscle finishing contraction
• Beginning to relax
• MP staying close to 0mV

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Phases

• Phase 3 End of Rapid Repolarization
• K returns to inside
• Cell returns to -90mV
• Almost ready
• Phase 4
• Na - K Pump turns on
• Sends Na out
• Brings K in
• Ready to do it all over again now ?

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Refractory PeriodsExcuse me!!! I hate to
interrupt again, but, who cares???

• Absolute Refractory Period
• Polarity of cell prohibits depolarization
• Relative Refractory Period
• Cell is returning to ready state for
  depolarization
• Impulse now is BAD!!!
• R on T Phenomenon
• Causes VT VF
• Treated with defibrillation
• Can be caused by
• Frequent FLBs
• EMT-P not pushing the sync button

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The Electrocardiograph (ECG, EKG)

• Electrical Activity
• Not Heart Action
• Records and impulses
• Paper runs at 25mm/s
• Counting Rates
• 300-150-100-75-60-50
• 6 second strip x 10
• 10 Second Strip x 6
• The little number on the monitor ?

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Lead Considerations

• 25,000 mVoltmeter
• Lead Views
• 1 Lateral
• 2 Inferior
• 3 Inferior

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The Components

• SA Node
• Internodal Pathways
• AV Junction
• AV Node
• Bundle of His
• L R Bundle Branch
• Purkinje Network
• Purkinje Fibers

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Ode to a Node

• Have a heart, and have no fear,The SA node is
  over here.Beating at a constant rate,60 100
  is really great.The AV node can make a show,If
  SA node has gone too slow.40 60 is not too
  badIf its all youve got, you will be
  glad.Should the whole thing drop its speed,His
  and bundle branches will take the lead.And that,
  my friend is the whole and part,Of the
  conduction system of your heart.
• Flip and See ECG, Cohn/Gilroy-Doohan

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Sino Atrial Node

• The Natural Pacemaker
• Connects directly to atrial fibers
• Fires 60-100 times per minute
• Wavelike Atrial Depolarization
• The P-Wave

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AV Junction

• Receives impulses from SA Node via the Atrial
  Cells
• An electrical funnel
• Impulses hit at various times
• Causes delay
• PR-I
• Susceptible to blockage
• Path from A to V
• Delivers impulse to the AV Node

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Atrio-Ventricular Node

• Lies between the Atria and Ventricles
• Collects impulses from above
• Stimulates Ventricles
• If unstimulated
• Intrinsic rate 40-60

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Bundle of His / Left and Right Bundle Branches

• Distributes Impulses from the Node
• The Ventricular Messengers

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Purkinje Network/Fibers

• Direct connection with ventricular tissue
• Intrinsic rate 20-40 if unstimulated

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The Six Step Approach

• What is the Rate?
• Is the Rhythm Regular?
• Are there P-Waves?
• Is the P-R Interval Normal?
• Is the QRS Complex Normal?
• Is There a P-Wave for Every QRS?

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Step 1 Rate

• Is the rate between 60-100 (Sinus)
• Between 40-60 (Junctional/Bradycardic)
• Above 100 (Tachycardic)
• Between 20-40 (Ventricular)

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Step 2 Regularity

• At-a-glance Does it look regular?
• Are the P-Waves evenly spaced?
• Are the QRS Complexes evenly spaced?

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Step 3 P-Waves

• Are P-Waves present?
• Are they upright and rounded?
• Are they irregular in any way Notched / Peaked /
  Depressed?
• Are they all the same?

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Step 4 P-R Interval

• Is the P-R Interval between 0.12-0.20?
• Is it too long / too short? (Block)
• Is it the same on every conduction?
• Is it absent?

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Step 5 QRS Complex

• Is it there?
• Is it between 0.04 - 0.12?
• Does it have any abnormalities? (Notched / Rabbit
  Eared / Wide / Bizarre)

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Step 6 P-QRS Married?

• Is there a P-wave for every QRS?
• Are there more P-Waves than QRS?
• Are the P-Waves after or within the QRS?

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Describe What Youve Found!!!

• IN GENERAL (underlying rhythms)!!!
• What are the abnormalities?
• Does it originate in the Sinus Node?
• Does it follow through from the Atria to the
  ventricles? Are there abnormal delays?
• What are the exceptions to the underlying rhythm?
  (Describe those also)

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Normal Sinus Rhythm

• Rate 60 - 100
• Regularity Very
• P-Waves Present and Normal
• P-R I 0.12-0.20 sec
• QRS 0.04-0.12 sec and Normal
• Married 1 P 1 QRS, no extras or shortages

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Sinus Arrhythmia

• Rate 60 - 100
• Regularity Irregular
• P-Waves Present and Normal
• P-R I 0.12-0.20 sec
• QRS 0.04-0.12 sec and Normal
• Married 1 P 1 QRS, no extras or shortages

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Sinus Tachycardia

• Rate Over 100
• Regularity Regular
• P-Waves Present and Normal
• P-R I 0.12-0.20 sec
• QRS 0.04-0.12 sec and Normal
• Married 1 P 1 QRS, no extras or shortages

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Sinus Bradycardia

• Rate Less than 60
• Regularity Regular
• P-Waves Present and Normal
• P-R I 0.12-0.20 sec
• QRS 0.04-0.12 sec and Normal
• Married 1 P 1 QRS, no extras or shortages

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Atrial Fibrillation

• Rate Usually tachy
• Regularity Irregular (Irregularly irregular)
• P-Waves Not Discernible
• P-R I Undeterminable
• QRS 0.04-0.12 sec
• Married Undeterminable

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Atrial Flutter

• Rate Usually tachy
• Regularity Atria Regular
• Ventricles May be Irregular
• P-Waves Sawtooth Pattern 21, 31, 41...
• P-R I 0.12-0.20 sec on conducting beat
• QRS 0.04-0.12 sec
• Married P-waves outnumber QRS
• (Picket fence)

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(Paroxysmal) Supra Ventricular Tach

• Rate 140-220
• Regularity Regular
• P-Waves Usually falls within the QRS-T complex
  ( sometimes not visible)
• P-R I Shorter than 0.12, or absent
• QRS 0.04-0.12 sec and Normal
• Married Undeterminable

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SVT

• WPW
• Usually based on Hx.
• Delta wave on Q
• Shortened PR-I
• No Verapamil Accessory Path use increase

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1st Degree Heart Block

• Rate 60 - 100
• Regularity Very
• P-Waves Present and Normal
• P-R I Longer than 0.20 sec
• QRS 0.04-0.12 sec and Normal
• Married 1 P 1 QRS, no extras or shortages

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2nd Degree Heart Block (Type 1) Wenkebach

• Rate Can be Normal, or usually brady
• Regularity Irregular
• P-Waves Present and Normal
• P-R I Lengthens until beat is dropped
• QRS 0.04-0.12 sec and Normal
• Married P-wave present on conducting beats,
  increased delay causes missed QRS

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2nd Degree Heart Block (Type 2)Mobitz II

• Rate Less than 60
• Regularity Irregular
• P-Waves Present, 21, 31, 41
• P-R I 0.12-0.20 sec on conducting beat
• QRS 0.04-0.12 sec, may begin to widen
• Married P-wave for every QRS and extras
  depending on conduction ratio

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3rd Degree Heart Block (CHB)Complete Heart Block

• Rate Ventricular Rate 40-60
• Regularity Atria-Regular
• Vent-Regular
• P-Waves Present and Normal
• P-R I Atria independent of Ventricles
• QRS Usually greater than 0.12 sec
• Married P-waves completely unrelated to QRS
  Complexes.

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Complete Heart Block
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Junctional Rhythm

• Rate 40-60
• Regularity Regular
• P-Waves Inverted, Retrograde or Absent
• P-R I Shortened or absent
• QRS 0.04-0.12 sec
• Married P-wave for every QRS, sometimes not
  visible

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Junctional
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Junctional Accelerated Rhythm

• Rate 60-100
• Regularity Regular
• P-Waves Inverted, Retrograde or Absent
• P-R I Shortened or absent
• QRS 0.04-0.12 sec
• Married P-wave for every QRS, sometimes not
  visible

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Junctional Tachycardia

• Rate 100-140
• Regularity Regular
• P-Waves Inverted, Retrograde or Absent
• P-R I Shortened or absent
• QRS 0.04-0.12 sec
• Married P-wave for every QRS, sometimes not
  visible

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Ventricular Tachycardia

• Rate 100-220
• Regularity Regular
• P-Waves None
• P-R I None
• QRS Greater than 0.12 sec
• Married NO

Well look at Torsades de Pointes in Lab
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Ventricular Tachycardia
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Ventricular Fibrillation

• Rate No ventricular rate
• Regularity Irregular
• P-Waves No
• P-R I No
• QRS No, unorganized ventricular baseline
• Married No

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Ventricular Fibrillation
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Asystole

• Rate 0
• Regularity N/A
• P-Waves None
• P-R I N/A
• QRS None
• Married No (verify a second lead)

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Asystole
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Agonal / Idioventricular

• Rate 20-40
• Regularity Irregular
• P-Waves None
• P-R I N/A
• QRS Wider than 0.12 sec
• Married NO (a dying heart)

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Idioventricular

• Less regular than this!

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Exceptions / Disruptions

• Premature Ventricular Contractions
• Premature Atrial Contractions
• Bundle Branch Blocks
• Pacer Considerations (Atrial, Ventricular or Both)

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Premature Ventricular Contractions

• Wide, Bizarre QRS Complex
• Always identify the underlying rhythm first
• Can appear in couplets, triplets, short runs of
  V-Tach, bigeminy and trigeminy
• Can be uni-focal or multi-focal
• Caused by random firing within the ventricles
• Not accompanied by a P-wave

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PVCs
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PACs

• P-QRS Complex appearing in an unexpected location
• Caused by a stimulus from within the Atria, but
  not from the SA Node

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PJC
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Bundle Branch Block

• Any rhythm having a BBB will have a widened twin
  peaked R-Wave

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Paced Rhythms

• Patients may have various types of pacemakers
• Atrial
• Ventricular
• Both
• Vertical spike on monitor is an indicator

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Paced Rhythms Various
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Artifact

• 60 Cycle Interference
• Loose Leads/Moving Ambulance

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In Summary

• Really Cool Physiology!!!
• GENERAL RULES to Interpretation
• Applicable to 3 lead monitoring
• Practice, Practice, Practice
• Remember the rules, NOT how it looks coming from
  one patient or one rhythm generator!!!

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Sources In order of preference

• Many of the pictures and info from
• Flip and See ECG, 2nd Edition
• Cohn/Gilroy-Doohan
• A great resource
• Paramedic Paramedic Textbook, Revised 2nd Edition
• Mick J. Sanders, Mosby
• ECGs Made Easy, 2nd Edition
• Barbara Aehlert, RN, Mosby
• Basic Dysrhythmias, Interpretation and
  Management, 3rd Edition
• Robert J. Huszar, Mosby