introduction to ekgs and ekg emergencies · 2021. 6. 3. · slide 30 2nd-degree type ii (mobitz ii)...
TRANSCRIPT
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Introduction to EKGs and
EKG EmergenciesJason Lucas, PhD, PA-C
Cardiology Critical Care ServiceCo-Director, Advanced Cardiovascular Fellowship
Atlanta, GA
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• The basic EKG format
• Calculation of intervals
• Placement of the leads
• Correlation of the leads with heart regions
• Method of interpretation of the ECG
• Emergency rhythms
What you will learn:
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Normal Coronary Anatomy
http://www.radiologyassistant.nl/data/bin/w430/a5097978474479_coronary-anatomy-RAO1.png
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Conduction of the Heart
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The EKG Paper
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• One small block is 0.04 seconds.
• Five small blocks = one big block.
• One big block = 0.20 seconds.
• 25 small blocks = 1 second.
• Five big blocks = 1 second.
• 1500 small blocks = 1 minute.
• 300 big blocks = 1 minute.
Counting Blocks
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Measurement of the Boxes
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Counting Blocks
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Lead Placement
Indiana.edu
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Lead Placement
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The Rhythm
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The PathSinoatrial node
AV node
Bundle of His
Bundle Branches
Purkinje fibers
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Cycle Initiation/Conduction:
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Cycle Initiation/Conduction:
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Repolarization of the ventricles generates a
current in the body and produces the T-wave on
the surface electrogram
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ECG Interpretation
What is your approach to reading an ECG?
•Rate
•Rhythm
•Intervals
•P wave
•QRS complex
•ST segment – T wave
•Axis
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Example Rhythm Strip
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Infarction Wave Abnormality EKG Segments Occlusion
Anterior ST Elevation V1, V2, V3, V4 Left Anterior Descending Artery
Inferior ST Elevation II, III, AVF Right Coronary Artery
Lateral ST Elevation I, AVL, V5, V6 Left Circumflex Artery
Posterior ST Depression, Tall R Wave V1, V2 RCA and/or LCX
Subendo Diffuse or Localized Changes,Non Q-Wave
Specific Regions
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Regions of the heart
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Putting it together
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Rate 60-100 bpm
P-P Regularity Regular
R-R Regularity Regular
P wave Present
P:QRS Ratio 1:1, associated
PR Interval Normal
QRS Width Normal
Normal Sinus Rhythm
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What is considered an EKG
Emergency?
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Cardioversion or Defibrillation
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Rate Varies, ventricular response can be fast or slow
P-P Regularity Chaotic atrial activity
R-R Regularity Irregularly irregular
P wave No discernable p-waves
P:QRS Ratio None
PR Interval None
QRS Width Normal, but can develop aberrant (wide) complexes
Atrial Fibrillation w/wo RVR
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Atrial RateVentricular Rate
Atrial Rate commonly 250-350 bpmVentricular Rate will vary with conduction
P-P Regularity Regular
R-R Regularity Usually regular, but may be variable
P wave “Saw-tooth” p-wave morphology
P:QRS Ratio Varies, can be 1:1, 2:1, 3:1, 4:1, etc.
PR Interval Varies
QRS Width Normal
Atrial Flutter
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Rate 20-40 bpm
P-P Regularity None
R-R Regularity Regular
P wave None
P:QRS Ratio None
PR Interval None
QRS Width Wide complex (≥ 0.12 s).
Ventricular Rhythms
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2nd-Degree Type II (Mobitz II)
https://www.google.com/search?q=third+degree+heart+block&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi_zJ_OzsnOAhWEXB4KHbaIC3UQ_AUICCgB&biw=976&bih=591#tbm=isch&q=second+degree+heart+block+type+II&imgrc=T3lPjYu9CEGCCM%3A
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2nd-degree type II (Mobitz II)
Second-degree type II (Mobitz II)
History •Always pathologic•Blockage occurs in the His bundle or the bundle branches
Symptoms •Asymptomatic, dyspnea, presyncope, syncope
EKG •Occasional loss of AV conduction for 1 beat
Treatment •Pharmacologic Therapy •Temporary Pacer (Internal/External) •Permanent Pacemaker (PPM) implantation•Biventricular pacemaker •Implantable cardioverter-defibrillator (ICD)
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Third degree heart block
(complete heart block)
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Third degree heart block
(complete heart block) Third Degree Heart Block
History •Always pathologic•Blockage occurs in the His bundle or the bundle branches •Cardiac function maintained by ventricular pacemaker or junctionalescape rhythm
Symptoms •Heart failure, presyncope, syncope
Physical Exam •Cannon a waves •BP fluctuations •Changes in 1st heard sound
EKG •No electrical communication between atria/ventricles•No P wave and QRS relationship
Treatment •Pharmacologic Therapy•Temporary Pacer (Internal/External) •Permanent Pacemaker (PPM) implantation•Biventricular pacemaker •Implantable cardioverter-defibrillator (ICD)
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Managment: Second degree II/3rd
degree AV block
• Unstable patients: – Immediate pharmacologic therapy:
• Atropine: 0.5 mg IV q 3-5 min, total dose 3 mg • Dopamine: 3 mcg/kg/min titrated to 20 mck/kg/min if needed • Dobutamine: 5 mcg/kg/min titrated to 40 mcg/kg/min if needed
– Temporary pacing (transcutaneous or transvenous) to increase HR and CO
• Hemodynamically Stable Patients: – First exclude reversible causes of AV block (ischemia,
hyperkamiea, AV nodal blocking drugs, hypothyroidism)– Consider permanent treatments:
• Permanent Pacemaker (PPM) implantation• Biventricular pacemaker • Implantable cardioverter-defibrillator (ICD)
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Temporary Pacer (External/Internal)
• Transcutaneous pacing (external pacing) – Indication:
• Bradycardia
– Technique: • Pads placed in the
anterior/posterior position and attached to defribillator/monitor
• Electrical capture: Pulse present with an EKG that shows wide QRS complex with a broad, tall T wave
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Temporary Pacer (External/Internal)
• Transvenous cardiac pacing (endocardial pacing) – Indications:
• Symptomatic bradycardiaunresponsive to drug therapy (atropine, epinephrine, dopamine) or transcutaneous pacing
– Technique: • Temporary solution: can be used as
bridge therapy to permanent pacing
• Pacing electrode threaded into the right atrium or right ventricle (or both)
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Pacemaker induced rhythm
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CRT-D
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Rate 200-250 bpm
P-P Regularity None
R-R Regularity Irregular
P wave None
P:QRS Ratio None
PR Interval None
QRS Width Variable with wide complexes
Polymorphic VT (Torsades)
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Rate Indeterminate
P-P Regularity None
R-R Regularity Chaotic Rhythm
P wave None
P:QRS Ratio None
PR Interval None
QRS Width None
Ventricular Fibrillation
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• Beyerbach, Daniel. Pacemakers and Implantable Cardioverter-Defibrillators: Practice Essentials, Overview, Evolution of the ICD. Clevland Clinic. 2016. http://my.clevelandclinic.org/services/heart/disorders/arrhythmia/heart-block
• Budzikowski, Adam. Third-Degree Atrioventricular Block Treatment & Management: Approach Considerations, Initial Management Considerations, Atropine and Transcutaneous/TransvenousPacing. June 2016. Medscape. http://emedicine.medscape.com/article/162245-overview
• Cazeau, Serve. Effects of Multisite Biventricular Pacing in Patients with Heart Failure and Intraventricular Conduction Delay. December 2015. http://emedicine.medscape.com/article/162007-treatment#d10
• Fang. Should Patients with Heart Block Receive Biventricular Pacing? 2015. Circulation. http://circep.ahajournals.org/content/8/3/722.full
• Sovari, Ali. Transvenous Cardiac Pacing: Background, Indications, Contraindications. February 2016. http://emedicine.medscape.com/article/80659-overview#a5
• Yalagadda, Chakri. Permanent Pacemaker Insertion: Background, Indications, Contraindications. Medscape. May 2014. http://emedicine.medscape.com/article/1839735-overview#a5