Myocardial Infarction

Question 1

Acute Myocardial Infarction is considered what

Answer 1

Acute coronary syndrome

Question 2

NSTEMI

Answer 2

Non-ST segment elevation
-May have normal ST segments, ischemia, ST depression
-elevated cardiac enzymes (trop)
-Need to draw serial trop levels

Question 3

STEMI

Answer 3

ST-Segment elevation

Question 4

Type 1 MI

Answer 4

Spontaneous MI caused by ischemia due to primary coronary event (plaque rupture, erosion, or fissuring, coronary dissection)

Question 5

Type 2 MI

Answer 5

Ischemia due to increased oxygen demand (htn) or decreased supply (coronary artery spasm or embolism, arrhythmia, hotn)

Question 6

Type 3 MI

Answer 6

Related to sudden unexpected cardiac death

Question 7

Type 4a MI

Answer 7

Associated with percutaneous coronary intervention

Question 8

Type 4b MI

Answer 8

Associated with documented stent thrombosis

Question 9

Type 5 MI

Answer 9

Associated with coronary artery bypass grafting

Question 10

Infarct Location

Answer 10

Affects predominantly the LV but damage can extend into the RV or the atria

Question 11

RV Infarct

Answer 11

-Usually results from obstruction of the RCA or dominant left circumflex artery;
-High RV filling pressure
-Often follows severe TR
-Reduced CO

Question 12

Inferoposterior infarct

Answer 12

-causes some degree of RV dysfunction
-Can cause hemodynamic instability

Question 13

Anterior Infarcts

Answer 13

-tend to be larger and result in a worse prognosis than inferoposterior infarcts
-Usually due to LCA obstruction especially in the anterior descending artery

Question 14

Infarct extent

Answer 14

-May be transmural or nontransmural

Question 15

Transmural infarct extent

Answer 15

-involve the whole thickness of myocardium from epicardium to endocardium
-characterized by abnormal Q waves on ECG

Question 16

Symptoms of MI

Answer 16

-Deep, substernal, visceral pain, aching or pressure
-Radiates to jaw, left arm, right arm, shoulder
-usually more severe and long standing than angina
-accompanied by dyspnea, N/V
-diaphoretic, syncope, 4th heart sound

Question 17

Diagnostic workup

Answer 17

-Cardiac markers: troponin-3 consecutive marker increase and calculate ck-mb (not highly reliable), Pro-BNP
-BMP, CBC, INR,
-CXR
-EKG
-Immediate coronary angio (unless fibrinolytics are given) for those with STEMI or complications (CP, Hotn, elevated cardiac markers, unstable arrhythmia)

Question 18

Broad Tx of MI

Answer 18

-Chewable aspirin 325mg
-Oxygen
-nitrates
-Triage to appropriate medical center
-Beta blockers
-Heparin or another anticoagulation
-Consider plavix load 300-600mg once (or prasugrel 60 mg po once or ticagrelor 180 mg PO once) if PCI is indicated
-Plavix 75 mg once/day if patients are at high risk or intolerant of aspirin
-GP IIb/IIIa inhibitors if PCI is indicated or if patients are high risk (abciximab, tirofiban, and eptifibatide)
-Maybe morphine for pain (cautiously as data suggest some P2Y12 receptor inhibitor’s could lead to worse patient outcomes)

Question 19

Inferior Limb Leads

Answer 19

II, aVF, III
-Inferior aspect of the LV

Question 20

Acute MI on EKG

Answer 20

-ST Elevation in > OR equal to 1mm in limb leads
-ST Elevation > or equal to 2 mm in pericardial leads
-2 contiguous leads
-New or presumed LBBB
-Elevated cardiac enzymes (Trop)
-Acute occlusion of coronary artery

Question 21

Lateral limb leads

Answer 21

-aVL, I and aVR, V5 and V6
-Lateral aspect of the LV
-LCx

Question 22

Anterolateral wall limb leads/Apical

Answer 22

-V5, V6
-Distal LAD, LCx or RCA

Question 23

Anterior Wall

Answer 23

-V3, V4
-LAD

Question 24

Septal limb leads

Answer 24

-V1 and V2
-Proximal LAD