ecg interpretation the basics and beyond.9.8.2016c.ymcdn.com/sites/ · pdf file8/19/2016 1 12...

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12 Lead ECG Interpretation: The Basics and Beyond

Cindy Weston, DNP, RN, CCRN, CNS-CC, FNP-BC

Assistant Professor

Texas A&M Health Science Center

Objectives

• Review the basics of 12 lead electrocardiogram

• Review when to order an ECG

• Identify the 12 most common rhythms and their treatment

• Identify and initiate treatment for acute myocardial infarction

Disclosures

• No Conflicts

“I struggled with everything cardiac in nursing school.”

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My Tips

• Understand Anatomy

• Take a Systematic Approach

• Ask yourself “Is this clinically significant?”

• Know common arrhythmias

• Know what to do about them

Conduction System

Willem Einthoven

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Action Potential

Intrinsic Rates

SA Node _______ beats/min

AV Node _______ beats/min

Bundle of HIS ____ beats/min

Purkinje Fibers ____ beats/min

60-100

40-60

20-40

20-40

Basic Rhythm

Depolarization

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Waves & Intervals

• P wave– Atrial depolarization (right then left)

– Usually upright (positive)

• PR interval– 0.12-0.20 seconds

– Measures start of atrial depolarization to start of ventricular depolarization

Waves & intervals

• QRS wave/interval– Q not always present, R first positive, S negative

after R

– Ventricular depolarization

– < 0.10-0.12

• T wave– Ventricular repolarization

– Usually upright

– May vary based on perfusion, electrolytes, meds

Waves and Intervals

• QT interval– < 0.40 seconds

– Corrected QTc (0.34-0.43)

– Men <0.47; women < 0.48

– > 0.50 DANGER!!!

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Waves and Intervals

• U wave– Repolarization of Purkinje fibers

– Electrolyte imbalance: hypokalemia, hypercalcemia, digoxin toxicity, use of some antiarrhythmics, congenital long QTc

ST segment

ECG Graph paperhorizontalSm box 0.04 secLg box 0.20 secverticalLg box 0.5mVSm box 0.1mV

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My Systematic Approach

• Rate

• Regularity

• Waves: p,q,r,s,t,u

• Intervals: PR, QRS, QTc

• ST segments

• R wave progression

• Axis: lead I & AVF

RATE

• # QRS 6 second strip x 10

• Memorize: 300, 150, 100, 75, 60, 50 rule

• 1500 / #small boxes between R-R waves

Regularity

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PQRST(U) waves

Intervals: PR, QRS, QTc

ST Segments

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12 LEAD ECG

12 snapshots of the electrical conduction in the heart

12 Views

• Limb leads give 6 views– I,II,III (Bipolar)

– AVR, AVL, AVF (unipolar, augmented vector)

• Precordial leads give 6 views– V1, V2, V3, V4, V5, V6

InferiorInferior

Late

raL

ate

ral

Einthoven’s Triangle

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Precordial chest leads “v” leads

12 Lead ECG

• 3 limb leads (I, II, III)

• 3 Augmented Vector leads (AVR, AVL, AVF)

• 6 Precordial leads (V1-V6)

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R wave progression

AXIS

Direction of electrical vector during ventricular depolarization

AXIS- NORMAL

Left- Wedding RingLead I

Right- Aggie RingLead AVF

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AXIS- LEFT Deviation

Left- Wedding RingLead I

Right- NO Aggie RingLead AVF

AXIS- RIGHT Deviation

Left- NO Wedding RingLead I

Right- Aggie RingLead AVF

AXIS- Extreme Right “no man’s land”

Left- NO Wedding RingLead I

Right- NO Aggie RingLead AVF

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Hypertrophy: LVH

• Left Axis Deviation

• R wave in AVL exceeds 13 mm

• R wave in V5 or V6 PLUS S wave in V1 or V2 exceeds 35 mm

• “eye ball test” QRS touch…

RVH

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RVH

BBB: Left

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BBB: Right

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BREAK TIME!!!

12 Common Issues

• Acute Coronary Syndrome

• STEMI

• NSTEMI/Unstable angina

Contiguous Leads

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STEMI

Brown, H. (2014). Synopsis and review of the American College of Cardiology Foundation/American Heart Association 2013 ST-elevation myocardial infarction guideline. AACN Advanced Critical Care, 25(2), 142-150.

Contiguous leads

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Contiguous Leads

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STEMI

Brown, H. (2014). Synopsis and review of the American College of Cardiology Foundation/American Heart Association 2013 ST-elevation myocardial infarction guideline. AACN Advanced Critical Care, 25(2), 142-150.

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STEMI

Brown, H. (2014). Synopsis and review of the American College of Cardiology Foundation/American Heart Association 2013 ST-elevation myocardial infarction guideline. AACN Advanced Critical Care, 25(2), 142-150.

STEMI

Brown, H. (2014). Synopsis and review of the American College of Cardiology Foundation/American Heart Association 2013 ST-elevation myocardial infarction guideline. AACN Advanced Critical Care, 25(2), 142-150.

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ST depression

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T-wave inversion

Q-waves

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NPs treating suspected Acute Coronary Syndrome

• Give ASA 325 mg x1

• STEMI– If outpatient EMS transport to ED with

notification

– If inpatient- prepare for reperfusion (STEMI protocol)

• ST depression/T-wave inversion/CP– Serial cardiac enzymes

– Serial ECGs

12 Abnormal Rhythms

• Premature Beats

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When to order a 12 lead

• Chest pain (duh!)

• Possibly indigestion, jaw pain, arm pain, anxiety, sense of doom….

• Palpitations

• Transient loss of consciousness

• New diagnosis HTN

• DX: HTN, Diabetes, Smoking, Hyperlipidemia

Routine $8.00 Diagnostic with interpretation $16

What about Routine Screen?

IPPE: Initial Preventative Physical Examination (no deductible or Co-payment!)

• G0403: Electrocardiogram, routine ECG with 12 leads; performed as a screening for the initial preventive physical examination with interpretation and report

• G0404: Electrocardiogram, routine ECG with 12 leads; tracing only, without interpretation and report, performed as a screening for the initial preventive physical examination

• G0405: Electrocardiogram, routine ECG with 12 leads; interpretation and report only, performed as a screening for the initial preventive physical examination

https://www.cms.gov/Outreach-and-Education/Medicare-Learning-Network-MLN/MLNProducts/downloads/MPS_QRI_IPPE001a.pdf

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12 Abnormal Rhythms

• Atrial Fibrillation

Atrial Fibrillation

Treatment Guidelines

• Antiarrhythmic– Rate Control

– Rhythm Control

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Anti-arrhythmics

Top 12 Abnormal RhythmsAtrial Flutter

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12 Abnormal RhythmsSupraventricular Tachycardia

SVT

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Treatment

• Vagal

• Adenosine

• Calcium channel blockers

• Digoxin

• Beta blockers

• Cardioversion

12 Abnormal RhythmsWPW

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12 Abnormal RhythmsSinus Tachycardia

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12 Abnormal RhythmsSinus Bradycardia

Junctional Rhythm

12 Abnormal Rhythms1 degree AV Block

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12 Abnormal Rhythms2nd Degree AV Block Type 1

12 Abnormal Rhythms2nd Degree AV Block Type 2

12 Abnormal RhythmsComplete Heart Block

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QUESTIONS?

cweston@tamhsc.edu

References

• Ecgpedia.org

• Thaler, M. (2015). The only EKG book you’ll ever need. 8th Ed. Lippincott Williams & Wilkins.

• Garcia, T. (2015). 12 Lead ECG: The art of interpretation. Burlington, MA: Jones & Bartlett Learning.

• Green, J. & Chiaramida, A. (2015). 12-Lead EKG Confidence: A step by step guide. New York: Springer Publishing Co.