Upload
others
View
23
Download
0
Embed Size (px)
Citation preview
9/13/2015
1
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.”
9/13/2015
2
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
9/13/2015
3
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
9/13/2015
4
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!!!
9/13/2015
5
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 paper
horizontalSm box 0.04 secLg box 0.20 secverticalLg box 0.5mVSm box 0.1mV
9/13/2015
6
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
9/13/2015
7
PQRST(U) waves
Intervals: PR, QRS, QTc
ST Segments
9/13/2015
8
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
Einthoven’s Triangle
9/13/2015
9
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)
9/13/2015
10
R wave progression
AXIS
Direction of electrical vector during ventricular depolarization
AXIS‐ NORMAL
Left- Wedding RingLead I
Right- Aggie RingLead AVF
9/13/2015
11
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
9/13/2015
12
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…
9/13/2015
13
RVH
RVH
BBB: Left
9/13/2015
14
BBB: Right
9/13/2015
15
9/13/2015
16
12 Common Issues
• Acute Coronary Syndrome
• STEMI
• NSTEMI/Unstable angina
Contiguous Leads
9/13/2015
17
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
9/13/2015
18
9/13/2015
19
Contiguous Leads
9/13/2015
20
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.
9/13/2015
21
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.
9/13/2015
22
ST depression
9/13/2015
23
9/13/2015
24
T‐wave inversion
Q‐waves
9/13/2015
25
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
9/13/2015
26
12 Abnormal Rhythms
• Atrial Fibrillation
Atrial Fibrillation
9/13/2015
27
Treatment Guidelines• Antiarrhythmic
• Rate Control
• Rhythm Control
Anti‐arrhythmics
Top 12 Abnormal RhythmsAtrial Flutter
9/13/2015
28
12 Abnormal RhythmsSupraventricular Tachycardia
SVT
9/13/2015
29
Treatment
• Vagal• Adenosine• Calcium channel blockers
• Digoxin• Beta blockers• Cardioversion
12 Abnormal RhythmsWPW
9/13/2015
30
12 Abnormal Rhythms
9/13/2015
31
12 Abnormal Rhythms
12 Abnormal Rhythms
9/13/2015
32
12 Abnormal Rhythms
12 Abnormal Rhythms
12 Abnormal RhythmsComplete Heart Block