Stemi vs no stemi

1. STEMI or NO STEMI
Presented By:
Marti Dunn
Brian Gerdes
Chris Cox

2. The purpose of this presentation is to review
and improve recognition of
STEMIs in the field.

3. Objectives
• Review anatomy of the heart
• Review rules for interpreting rhythms
• Review recognition of STEMI and NO STEMI
• Review STEMI Imposters

4. Anatomy of the Heart
• Heart is located to the left side of a patient’s
chest
• It is about the size of a human fist
• The heart is made out of cardiac muscle
• Cardiac muscle does not regenerate(when it
dies it does not reproduce itself)

5. • Coronary Arteries are sole suppliers of
arterial blood to the heart
• They deliver 200 to 250 mL of blood to the
myocardium each minute during rest
• The left coronary artery carries about 85%
percent, of the blood supply
• The right coronary artery carries the rest
about 15 %

6. • Left main coronary artery supplies the left
ventricle and part of the right ventricle
• It has two main branches are the left
anterior descending, artery and the
circumflex artery

7. Interpreting a 12 Lead ECG

8. • Remember that each small box is equal to 0.04
seconds
• There should be five small boxes in every big box
• One big box equals 0.20 seconds moving
horizontal along the ECG
• One box vertically equals one mm of elevation
• One big box equals five mm of elevation

10. Rules for Interpreting a Rhythm
• Rate
– Is the heart rate fast or slow?
• 59 and below is bradycardic
• 60 to 100 is normal
• 101-150 is tachycardia
• 150 and above is SVT

11. Bradycardia
Normal
Tachycardia
SVT

12. Rhythm
• Is the rhythm regular or irregular?
Regular
Irregular
Regular

13. QRS
• Is the QRS narrow or wide
Wide QRS
Narrow QRS

14. – P-Wave
• Is there a P-wave with every QRS and are they
right side up?
Without P-Wave
With P-Wave

15. – Is there elevation or no elevation?
Elevation
Elevation
No Elevation

16. • You can determine the underlying rhythm
from a four lead ECG six second strip but
definatively a 12 Lead confirms diagnosis of
underlying rhythm, the presence of a STEMI
and Imposters.
• Just because a 4 lead looks normal DO NOT
assume that the 12 lead is going to look
normal.

17. Myocardial Infarction

18. •A sudden and total blockage or near
blockage of blood flowing through the
affected coronary artery to a area of heart
muscle
•This blockage results in ischemia, injury and
necrosis to the area of the myocardium distal
to the occlusion
•Acute myocardial infarction most often is
associated with atherosclerotic heart disease

19. STEMI (ST Elevation MI)
• The ST segment is the flat, isoelectric section of the
ECG between the end of the S wave (the J point) and
the beginning of the T wave. It represents the interval
between ventricular depolarization and repolarization.

20. The J-point is the point by which the s wave meets
the ST segment. This point is crucial in defining
what is a STEMI and what is NOT A STEMI.

21. Broad, asymmetrically peaked or ‘hyperacute’ T-
waves are seen in the early stages of ST-
elevation MI (STEMI) and often precede the
appearance of ST elevation and Q waves.

22. The Three I’s
Ischemia
Injury
Infarct

23. Ischemia
Lack of oxygen
to the tissue
represented by
ST depression
and/or T Wave
inversion

24. Injury
Lack of oxygen
to the tissue
(ischemia)
represented by
ST elevation

25. Infarct
Death of tissue
may or may
not result in Q
waves

26. • “I See All Leads” is a nemonic to help with the
location on a 12 lead EKG where the injury to the
cardiac muscle is occurring, it is not the only way,
but is the most common way.
• Inferior
– II, III, AvF
• Septal
– V1, V2
• Anterior
– V3, V4
• Lateral
– V5, V6, I and AvL

28. • When determining if a patient is having a
STEMI the provider has to use the ST segment
to determine if an event is occurring
• The ST segment (the isoelectric line that starts
at the J-point and goes to the start of the T-
wave) will be elevated in relation to the
isoelectric line.
• Elevation in this segment determines if a
STEMI is occurring or not
• Not all AMI will show up as an elevation of the
ST segment

31. Normal 12 Lead EKG
•Normal Rate
•Regular Rhythm
•P-Wave with every QRS
•Narrow QRS complex
•No elevation in any leads
NOT A STEMI

32. Normal 12 Lead EKG
•Normal Rate
•Regular Rhythm
•P-Wave with every QRS
•Narrow QRS complex
•No elevation in any lead
NOT A STEMI

33. Is this a STEMI?
•Regular Rate
•Regular Rhythm
•P-wave with every QRS complex
•Narrow QRS complexes
•Elevation in leads II, III, AvF with recipricol changes in V2 and V3

34. THIS IS A STEMI!!

35. Remembering your rules.
Is this a STEMI?
YES ,this is a STEMI!

36. Remembering your rules.
Is this a STEMI?
Yes this is a STEMI!

37. • The numbers at the top left of the print out
can be trusted as accurate and are scientific
• The interpretation in the upper right hand side
of the print out cannot always be trusted
• DO NOT BASE YOUR INTERPRETATION ON
THIS!!

38. STEMI Imposters

39. What are STEMI Imposters?
• STEMI Imposters are conditions that mimic a
STEMI. They cause a 12 Lead to show
elevation but no STEMI is occuring.
• Now take that definition with a grain of salt as
just because they are having AMI symptoms
and showing an imposter does not mean they
are not having a cardiac event of some kind.
• TREAT YOUR PATIENT AND NOT YOUR
MONITOR.

40. Left Ventricular Hypertrophy (LVH)
• LVH is responsible for up to 30% of ST
elevation. It’s defined as an increase in mass
to the left ventricle, often in response to
chronic hypertension. As the heart beats
continuously against a higher diastolic
afterload, cardiac tissue surrounding the left
ventricle grows, stealing space, and thus
volume, from its ventricle.

41. Left Ventricular Hypertrophy (LVH)
• Due to the abnormally thick left ventricular
muscle wall
• The electrical impulses running through the
muscle causing it to contract will have a large
amplitude in the height and depth of the QRS
complexes

42. How do we measure for LVH?
• We need two pieces of information
–The S wave depth in V1 or V2 (Take the
largest negative deflection from the
isoelectric line)
–The R wave height of V5 or V6 (Again take
the largest positive deflection)
• Now count the boxes of each of the two
deflections and add them together. You have
LVH if the result is greater than 35mm

44. • In the normal conduction of the heart, the
electrical impulse initiated in the right atrium
travels through the internodal pathways to the
AV node, down through the bundle of HIS and
eventually down to the right and left bundles
• In this way, the cardiac muscle contracts
sequentially and efficiently
Bundle Branch Blocks

45. • A Bundle Branch Block, however, slows or
stops the conduction through one of the
bundles.
• The block is often caused by death of the
specialized conduction cells that transmit the
electrical impulse, leaving the affected
myocardium primed to contract, but without a
signal.
• This could be caused by cardiac surgery, LVH
or AMI, to name some of the more common
problems

46. • The block that we are most concerned with as
an impostor is the Left Bundle Branch Block
(LBBB)
• Because of its negative deflection and long
electrical impulse around the left side of the
heart, the EKG strip tracing has a STEMI look
to it.

47. How do we determine if we have a LBBB?
First we have to look at the width of the QRS
complex to see if it is wide.
• We can look at the machine values for
the QRS. Which will need to be greater
than .12 sec.
• We can look the 12 lead ECG and see if
the QRS is greater than three small blocks
in V1.

48. • If the QRS width is greater than .12 sec than
we have a Bundle branch.
• Now we look at the lead V1 to determine if it
is a Right Bundle Branch Block (RBBB) or LBBB.
• If the QRS complex has a positive deflection
than it is a RBBB (think of a turn signal in a
car).
• If there is a negative deflection to the QRS
complex than it is a LBBB.

51. Early Repolarization
• Early Repolariation has historically been
thought of as being in good health due to
being found in younger athletic persons.
• Early repolariztion has the characteristics of a
“J wave” or “J point elevation”. This can be
seen on the EKG if there is elevation of less
than 0.1mV at the J point with a notched look
that drops down to the isoelectric line before
the raise of the T wave giving the look of hook.

52. • Due to the history of Early Repolarization
being a young/healthy person finding be
careful in diagnosing this on a EKG of anyone
over the age of 50.

54. Paced Rhythms
• Due to the damage to the heart a patient may have a
pacemaker implanted to effect the electrical impulse
to cause contraction of either the Atrium or the
Ventricles
• Depending on the placement location of the
pacemaker electrode on he heart the strip tracing
may have a normal QRS width with a P wave, or no P
wave and a wide QRS complex.
• With a paced rhythms the pacemaker sets off an
electrical impulse to cause contraction. This impulse
may be seen prior to the P wave or QRS complex
with a “pacer spike”. This spike will be of low voltage
and short duration at the start of the P wave or QRS
complex.

56. Hyperkalemia
• Hyperkalemia is a abnormally high
level of potassium in the blood.
• This condition my be caused by acute
or chronic renal failure, burns, crushing
injuries and severe infections or other
conditions in which large amounts of
potassium are released.

57. • P wave widens and flattens
• PR segment lengthens
• P waves eventually disappear
• Prolonged QRS interval with bizarre QRS
morphology
• High-grade AV block with slow junctional and
ventricular escape rhythms
• Any kind of conduction block (bundle branch
blocks, fascicular blocks)
• Sinus bradycardia or slow AF

58. Early onset of Hyperkalemia

59. Severe Onset of Hyperkalemia!!

60. Treatment for AMI in
Pre -Hospital setting

61. Aspirin
Aspirin decrease inflammation,
Dilates peripheral vessels and decreases
platelet aggregation ,
The use of aspirin , is strongly
recommended for all patients with
acute coronary syndrome

62. Nitroglycerin
Is a vasodilation agent that has beneficial
hemodynamic effects
Dilation arterioles and veins in the periphery (
reducing preload)
Dilation of the coronary arteries (reducing the
work load )

63. Oxygen
Oxygen is odorless
tasteless, colorless gas that is
present in room air at a
concentration of
approximately 21%
Oxygen is an important
emergency drug used to
reverse hypoxemia in doing
so it helps oxidize glucose
to produce adenosine
triphosphate ( aerobic
metabolism)
Oxygen may help reduce
the size of infarcted tissue
during an acute myocardial
infarction

64. Morphine
• Natural opium alkaloid
that has a primary effect of
analgesia
• Secondary pharmacological
effects include depressed
responsive of alpha-
adrenergic receptors (
producing peripheral
vasodilation )
• Morphine decreases
preload and after load it
may decrease myocardial
oxygen demand .

65. Dilaudid
• Analgesic opiate agonist
• Onset IN/IM within 15 min
• Duration 4-5 hrs
• Moderate to severe pain
• Analgesia

66. Conclusion
• STEMI recognition is one of the most
important things we do as Medics
• Remember the five rules for interpreting a 12
lead:
– Rate
– Regular or Irregular
– Wide or Narrow QRS
– P-wave with every QRS
– Elevation or No Elevation

67. • Remember your Imposters and how to detect
them
– Bundle Branch Blocks
– LVH
– Paced Rhythm
– Benign Early Repolarization
– Hyperkalemia
• Remember the treatment for a AMI
– Morphine
– ASA
– Oxygen
– Nitro