Download STEMI Mimics

ONTARIO
BASE HOSPITAL GROUP
Chapter 12
for 12 Lead Training
-STEMI MimicsOntario Base Hospital Group
Education Subcommittee
2008
TIME IS
MUSCLE
STEMI Mimics
AUTHOR
REVIEWERS/CONTRIBUTORS
Greg Soto, BEd, BA, ACP
Neil Freckleton, AEMCA, ACP
Hamilton Base Hospital
Niagara Base Hospital
Jim Scott, AEMCA, PCP
Sault Area Hospital
Ed Ouston, AEMCA, ACP
Ottawa Base Hospital
Laura McCleary, AEMCA, ACP
SOCPC
Tim Dodd, AEMCA, ACP
Hamilton Base Hospital
2008 Ontario Base Hospital Group
Dr. Rick Verbeek, Medical Director
SOCPC
OBHG Education Subcommittee
STEMI Mimics: Say what?
K Mimics
in 12 Lead ECG interpretation
refer to physical or electrical factors that
can make interpretation difficult.
K Also referred to as imitators, mimickers
and maskers
K These factors can either hide or mimic
ECG patterns consist with an ACS
OBHG Education Subcommittee
Mimics – The List
a.
b.
c.
d.
e.
f.
g.
Bundle Branch Blocks
Left Ventricular Hypertrophy (LVH)
Electrolyte disturbances
Digitalis effects
Pericarditis
Benign Early Repolarization
Pacemaker rhythms
OBHG Education Subcommittee
ONTARIO
BASE HOSPITAL GROUP
a. Understanding Bundle
Branch Blocks
a. Objectives
K Describe
the properties of the
intraventricular conduction system
K Describe the clinical and reperfusion
relevance for BBB identification
K Using turn signal method, determine the
presence and location of bundle branch
block
K Describe the hemodynamic and conduction
system problems associated with a bundle
branch block
OBHG Education Subcommittee
Bundle Branch A&P
K Block
of left or right
bundle branch
K Fascicle of the
conduction system
K “Functional syncytium”
K Bundle branch blocks
= ventricles out of
sync
OBHG Education Subcommittee
Pathophysiology of BBB
K Caused
by ischemia acutely
K Can be a result of congenital defects
K Can be secondary to hypertension or
degenerative heart disease
K Some people live with a BBB and the
limitations
OBHG Education Subcommittee
Bundle Branch Block (BBB)
K New
z
or presumably new
Candidate for acute reperfusion
therapy
K How
do we know it is a new
onset?
K May mask or mimic acute ECG
changes
K How do we triage and treat?
OBHG Education Subcommittee
What happens in a BBB?
K Unaffected
bundle branch depolarizes
normally
K Diseased bundle branch does not deliver
the impulse to the ventricle
K Wave of depolarization is spread from the
unaffected side, cell to cell, to the other
ventricle
K It takes longer to depolarize in this fashion,
so the QRS is widened as a result
OBHG Education Subcommittee
BBB Identification
KSupraventricular
rhythm in
origin
KWide
QRS (120ms or more)
OBHG Education Subcommittee
Diagnosing BBB
K Use
VI
K Circle the J point
K Find the terminal
deflection
K Shade in an
arrowhead pointing
up or down
K Apply “turn signal”
criteria
OBHG Education Subcommittee
Real-world step by step
From ECG interpretation or initial
12 lead look you will likely find
wide looking QRS with notching
2. This should clue you into look for
QRS duration in 12 Lead info
section at top of printout
3. Determine LBBB or RBBB in a
wide complex SVT by using VI
1.
OBHG Education Subcommittee
Example: LBBB
OBHG Education Subcommittee
Example: LBBB
OBHG Education Subcommittee
Example: RBBB
OBHG Education Subcommittee
Example: RBBB
OBHG Education Subcommittee
Practice Cases
Bundle Branch Blocks
OBHG Education Subcommittee
Left BBB
OBHG Education Subcommittee
Right BBB
OBHG Education Subcommittee
Incomplete Left BBB
OBHG Education Subcommittee
Left BBB
OBHG Education Subcommittee
Right BBB
OBHG Education Subcommittee
Right BBB
OBHG Education Subcommittee
Left BBB
OBHG Education Subcommittee
Right BBB
OBHG Education Subcommittee
Left BBB
OBHG Education Subcommittee
Right BBB
OBHG Education Subcommittee
Left BBB
OBHG Education Subcommittee
Left BBB
OBHG Education Subcommittee
Clinical Significance of BBB
KBBB
caused by AMI
z 60%-70%
association with pump
failure
z 40%-60% mortality without
reperfusion
OBHG Education Subcommittee
Clinical Significance of BBB
KCan
mimic ACS
KCan
hide evidence of
ACS
OBHG Education Subcommittee
Bundle Branch Block
K May Produce
z ST elevation
z ST depression
z Tall T waves
z Inverted T waves
z Wide Q waves
K May Hide
z ST elevation
z ST depression
z Tall T waves
z Inverted T waves
z Wide Q waves
OBHG Education Subcommittee
The Solution
Lives Saved (per 1 ,0 0 0 )
Fibrinolytic Therapy Trialists’ (FIT) Collaborative Group, 1994
OBHG Education Subcommittee
The Problem
K Critical
to reperfuse patients with
new or presumably new BBB
produced by ACS
K ACS
harder to identify on ECG when
BBB present (how do you know it is
new?)
OBHG Education Subcommittee
Clinical Significance of BBB
KCan
mimic ACS
KCan
hide evidence of
ACS
KUsually
not to be trusted!
OBHG Education Subcommittee
The Solution
New or presumably new BBB is an
indication for thrombolytic therapy
z Base
your triage decision on the
patient presentation. i.e.: on
suspicion of AMI
z CTAS
with hospital notification - not
necessarily a Cardiac or STEMI
Alert
OBHG Education Subcommittee
ONTARIO
BASE HOSPITAL GROUP
b. Left Ventricular
Hypertrophy (LVH)
b. Objectives
KIdentify
evidence of left ventricular
hypertrophy and strain
KDescribe the clinical implications
of ventricular enlargement
OBHG Education Subcommittee
Left Ventricular Hypertrophy
K LVH-increased
pressure or volume
K Found in mitral and aortic stenosis,
cardiomyopathy, hypertension, IHD
K Experts disagree on ECG accuracy
K Nonetheless, the criteria are proven
K Definitive Dx: echocardiography
OBHG Education Subcommittee
LVH Voltage Criteria – Rule of 35’s
K If
they add up to more than 35 mm,
and the patient is over 35 years old,
then voltage criteria for LVH is met
K Measure deepest S wave in either V1
or V2; add to tallest R wave in V5 or
V6
K Look for aVL pattern
K Then look for “strain”
OBHG Education Subcommittee
LVH Voltage Criteria
17
26
OBHG Education Subcommittee
LVH Voltage Criteria
KR
wave in aVL is >11 mm
OBHG Education Subcommittee
Strain Pattern
Ka
pattern of asymmetrical ST depression & Twave inversion most commonly seen in V5 &
V6 (sometimes in I, aVL, V4)
K Increases sensitivity of voltage criteria for LVH
OBHG Education Subcommittee
Why high amplitude QRS in LVH?
K voltage
of QRS complex is
proportional to amount of muscle
being depolarized
K higher voltage suggests overgrowth of
muscle in that chamber
K LV larger muscle mass = larger
pattern in QRS
OBHG Education Subcommittee
LVH w/strain – rule of 35
OBHG Education Subcommittee
LVH w/strain – rule of 35
OBHG Education Subcommittee
None
OBHG Education Subcommittee
LVH w/strain/aVL > 11mm
OBHG Education Subcommittee
None
OBHG Education Subcommittee
LVH – aVL > 11mm
OBHG Education Subcommittee
ONTARIO
BASE HOSPITAL GROUP
c. Electrolyte Disturbances
Page, 12-Lead ECG for Acute and Critical Care Providers
© 2006 by Pearson Education, Inc. Upper Saddle River, NJ
c. Objectives
K List
the causes and clinical implications of
various electrolyte abnormalities
K Describe ECG changes in hyperkalemia &
hypokalemia
OBHG Education Subcommittee
Effects of Potassium
K Potassium
(K+)
Prevents shortened action potential
z Allows for organized fast heart rates
z Protects from excitability
z Slows heart in vagal responses
z
OBHG Education Subcommittee
Hyperkalemia
K
K
1.
2.
3.
Hyperkalemia is a potentially lifethreatening metabolic problem
Caused by:
inability of the kidneys to excrete
potassium
impairment of the mechanisms that move
potassium from the circulation into the
cells
or a combination of these factors.
OBHG Education Subcommittee
Hyperkalemia
K Symptoms
are fairly nonspecific, and
generally include malaise, palpitations and
muscle weakness
K SOB may indicate metabolic acidosis
K Potentially life-threatening problem
K Lethal injection: Along with pancuronium
(NMB) and thiopental, potassium chloride
is used in 37 states of the US to execute
prisoners.
OBHG Education Subcommittee
Hyperkalemia
K Serum
levels above normal range
K Most common cause is renal failure
K Sinus node can quit at 7.5 mEq/L
K VF or asystole at 10–12 mEq/L
OBHG Education Subcommittee
Hyperkalemia – ECG
K Tall
T waves with a
narrow base
K QRS widens
K Broad S waves in V
leads
OBHG Education Subcommittee
Hyperkalemia – ECG
K ST
segment
disappears
K “T
wave grows,
P wave goes”
K Sine
waves in
severe cases
OBHG Education Subcommittee
Hypokalemia
K Serum
level below 3.5–5.0 mEq/L
K Caused by vomiting, diarrhea,
diuretics, gastric suctioning
K Hypomagnesemia
K Muscle weakness, polyuria
K Digitalis can take advantage and
cause Torsades de pointes
OBHG Education Subcommittee
Hypokalemia
K ECG
Changes
ST segment depression
z T waves flatten or join U waves
z U waves get larger than Ts
z QT interval appears to lengthen
z PR interval increases
z
OBHG Education Subcommittee
Hypokalemia
K Potassium
KU
normal
waves overtake T
OBHG Education Subcommittee
ONTARIO
BASE HOSPITAL GROUP
d. Digitalis Effects
d. Objectives
KRecognize
the signs and
symptoms of digitalis toxicity
KDescribe the ECG criteria for
digitalis effect
OBHG Education Subcommittee
Digitalis Toxicity
K also
known as digoxin and digitoxin (trade
name = Lanoxin)
K strengthens contraction of the heart muscle
K slows the heart rate (via PNS stimulation)
K helps eliminate fluid from body tissues
K used to treat congestive heart failure and is
also used to treat arrhythmias such as
Atrial Fib.
K derived from the foxglove plant
OBHG Education Subcommittee
Digitalis Toxicity
K Potential
for serious
adverse effects
K Narrow window between
therapeutic & toxic effect
S&S of toxicity:
K Headache, nausea,
vomiting, diarrhea
K Altered colour perception:
halo vision
K Generalized malaise,
delirium
OBHG Education Subcommittee
12 Lead & Digitalis Effect
K
K
K
K
K
60% of those on “Dig” have it
ST segment depression
Scooped out appearance
Best seen in inferior/lateral leads
Not pathologic but result of dig toxicity
OBHG Education Subcommittee
Digitalis effect
OBHG Education Subcommittee
ONTARIO
BASE HOSPITAL GROUP
e. Pericarditis
e. Pericarditis
K Describe
the pathology and pattern of
signs and symptoms
K Demonstrate the assessment steps to
recognized pericarditis
K Describe ECG evidence of pericarditis
pacemaker rhythms early
repolarization
OBHG Education Subcommittee
Pericarditis
K Inflammation
of the
pericardium
K Occurs in younger
patients without
history of CAD
K You should pick
this up from
assessment more
than 12 Lead ECG
interpretation
OBHG Education Subcommittee
Normal Pericardium
OBHG Education Subcommittee
Causes of Pericarditis
K Infection:
viral, bacterial, fungal,
parasitic
K Ideopathic
K Neoplastic
K Immune disorder
K Traumatic
K Iatrogenic: CPR, radiation injury,
instrumentation, drugs
OBHG Education Subcommittee
Pericarditis
K Signs
and Symptoms
Chest pain, dyspnea, tachycardia, fever,
weakness, chills
z Chest pain sharp, radiating to back,
neck, jaw
z Made worse by lying flat, twisting
z Made better by leaning forward
z
OBHG Education Subcommittee
Pericarditis
K Often
pleuritic pain, worse on
inhalation
K Pain can last for hours or days
K Pericardial friction rub
z
Heard over left lower sternal border
OBHG Education Subcommittee
Pericarditis ECG Criteria
K ST
segment
elevation
K Concave in all
leads
K T wave elevation
K PR depression
OBHG Education Subcommittee
Pericarditis
OBHG Education Subcommittee
Pericarditis: Diagnosis
Physical Criteria:
(CP, relieving
criteria,
pleuritic)
z No response to
NTG
z Pericardial rub
z ECG changes that
do not localize
z
OBHG Education Subcommittee
ONTARIO
BASE HOSPITAL GROUP
f. Other STEMI mimics
Ventricular Rhythms
Paced
OBHG Education Subcommittee
Early Repolarization
K Occurs
in young,
healthy people
K African American
males
K Notched J point
K Concave elevation
K Leads II, III, aVF,
V4–V6
K Lateral leads
OBHG Education Subcommittee
Benign Early Repolarization
• Look for notch at J-point
– ST segment and J-point create
a “fish hook” appearance
OBHG Education Subcommittee
Benign Early Repolarization
OBHG Education Subcommittee
ONTARIO
BASE HOSPITAL GROUP
PRACTICE ECGs
AFib w/ PVCs and RBBB
OBHG Education Subcommittee
A Fib w/ RBBB
OBHG Education Subcommittee
Hyperkalemia
OBHG Education Subcommittee
NSR – No STEMI
OBHG Education Subcommittee
NSR – Extensive Anterior AMI
OBHG Education Subcommittee
NSR w/ LVH w/strain
OBHG Education Subcommittee
NSR – old Septal MI
OBHG Education Subcommittee
S Brad – Lateral STEMI w/RCs
OBHG Education Subcommittee
NSR w/LBBB
OBHG Education Subcommittee
BER
OBHG Education Subcommittee
NSR – Inferior STEMI 15 lead
OBHG Education Subcommittee
SVT w/RBBB
OBHG Education Subcommittee
1st° Block w/PVCs – RBBB
OBHG Education Subcommittee
NSR – Inferior STEMI w/RCs
= 15 lead
OBHG Education Subcommittee
LVH – rule of 35
OBHG Education Subcommittee
NSR, digitalis effect, prolonged QT
OBHG Education Subcommittee
2nd° Type I - LBBB
OBHG Education Subcommittee
LBBB
OBHG Education Subcommittee
A Fib – RBBB
OBHG Education Subcommittee
Pericarditis
OBHG Education Subcommittee
NSR – old Inferior MI
OBHG Education Subcommittee
3rd° block – broad Ischemia
OBHG Education Subcommittee
S Brad – Anteroseptal & Inferior STEMI
OBHG Education Subcommittee
ONTARIO
BASE HOSPITAL GROUP
QUESTIONS?
ONTARIO
BASE HOSPITAL GROUP
Well Done!
Education Subcommittee
START
QUIT