Ch. 9: Infarction Flashcards
1
Q
what is an infarction?
A
- complete occlusion of coronary artery
- necrosis
- no depolarization
- no contraction
- heart gets blood supply from coronary arteries
- blockage= myocardium has no blood supply
- PRIMARILY LEFT VENTRICLE
2
Q
how are infarctions diagnosed?
A
- history and physical exams
- cardiac enzymes
- EKG
3
Q
how will an EKG possibly show an infarction?
A
- which coronary artery is blocked
- reveal conduction blocks caused by infarction
- reveal reduced blood supply to heart
4
Q
what is the same as an infarction?
A
- myocardial infarction
- coronary occlusion
- heart attack
5
Q
what is necrotic tissue?
A
- functionally dead
- no depolarization
- may compromise hemodynamics
6
Q
what is the Infarction Triad?
A
- Ischemia (lack of blood flow)
- Injury (to heart tissue)
- Necrosis (dead tissue)
- basis for recognizing and diagnosing MI
7
Q
What is Ischemia?
A
- lack of blood flow
- Pathological
- may cause enigma
8
Q
How do you identify Ischemia?
A
- Inverted T wave in absence of MI
- inverted T wave and symmetrical
- T wave inversion V2-V6
9
Q
Injury
A
- acuteness of infarction
- ST seg elevation
- may be slight
- may be >10mm
10
Q
ST elevation
A
- alone may indicate infarction
- acute
- over time ST elevation returns to baseline
- Ventricular aneurysm may cause persistent ST elevation in most chest leads
11
Q
ST depression
A
- subendocardial infarction
- positive stress test
- digitalis
- angina attack
12
Q
When does ST depression occur?
A
- with ischema
- ventricular strain
- electrolyte abnormality
- subendocardial infarction
- elevated rate
13
Q
J Point (Junctional Point)
A
- end of QRS and beg. of ST set
- elevation is common in young, healthy indivs
- measure ST seg depression 80 sec past J point
14
Q
Subendocardial Infarction
A
- ST depression
- Flat, Horizontal, Downward sloping
- Non Q wave infarction
- small area just beneath endocardial lining
15
Q
Necrosis
A
- Q wave
- significant
- at least 0.04s in duration
- at least 1/3 of QRS amp
- height and depth
16
Q
How to identify infarctions
A
- scan all leads except QVR for:
- Q waves
- ST seg depression or elevation
- inverted T waves
17
Q
Anterior Infarction
A
- positive chest leads record negative
- V1-V4
- Q wave
- anterior descending art
18
Q
Lateral Infarction
A
- positive L arm leads record negative
- Lead 1 and AVL
- Q wave
- occlusion of circumflex art
19
Q
Inferior Infarction
A
- Positive L arm leads record negative
- Leads 2, 3, and AVF
- Q wave
- terminal branch of either R/L CA
20
Q
Posterior Infarction
A
- ST depression
- V1 and V2
- Large/Tall R waves
- may be Q in V6
- R coronary art
21
Q
Coronary arteries
A
- L coronary artery: Circumflex and Anterior Descending
- R coronary artery
22
Q
Left ventricle (lateral)
A
- Q wave
- Lead 1
- AVL
23
Q
Left ventricle (anterior)
A
- Q wave
- V1
- V2
- V3
- V4
24
Q
Antero-septal (septum)
A
- Q waves
- V1
- V2
(negative QRS in V1-V4, V5-V6 norm have insignif Q waves)
25
Q
Antero-lateral
A
- Q waves
- V3
- V4
(negative QRS in V1-V4, V5-V6 norm have insignif Q waves)
25
Q
Antero-lateral
A
- Q waves
- V3
- V4
26
Q
T/F: anterior infarctions are very deadly
A
T: widow maker. immediate treatment improves survival
27
Q
Lateral Infarct
A
- depolarization away from positive leads
- Lateral L ventricle involved
- Q wave
- Lead 1
- AVL
28
Q
Inferior infarction
A
- depolarization away from positive leads
- 2, 3, AVF negative sometimes
- inferior wall of L ventricle involved
- Q wave
- Lead 2
- Lead 3
- AVF
29
Q
Acute Anterior infarction
A
- V1-V4 still negative
- ST elevation
- significant Q waves
- V1
- V2
- w/ possible significant Q waves in V1 and V2
30
Q
Acute posterior infarct
A
- ST depression
- same as posterior infarct, difficult to diagnose on EKG
- Large R wave
- V1
- V2
31
Q
Hemiblock
A
- Leads to MI, hard to identify on EKG
- associated with decreased blood supply
- LBB- 2 divisions
- anterior and posterior
32
Q
Hemiblock (anterior)
A
- LAD
- normal or slightly widened QRS
- Large Q wave in lead 1
- Large S wave in Lead 3
- occluded anterior descending coronary art
- anterior infarction (1/2 develop anterior hemiblock)
33
Q
Posterior hemiblock
A
- RAD
- normal or slightly widened QRS
- Large S wave in Lead 1
- Large Q wave in Lead 3
