Myocardial Infarction Flashcards
1
Q
Anterior MI
A
- Left anterior descending coronary artery
- Majority of the heart supplied by LAD
- STEMI V1-V4
2
Q
Inferior Wall MI
A
- Right coronary artery
- ST segment elevation in II, III, and AVF
- ST segment depression in I, AVL, or both (>1mm)
- Inferior wall supplied by the RCA in LCx
3
Q
Lateral Wall MI
A
- ST elevation in I, AVL, V5, V6
- High lateral wall (I and AVL)
- Low lateral wall (V5, V6)
4
Q
Posterior MI
A
- ST segment depression in the septal and anterior precordial leads (V1 to V4)
- The ratio of the R wave to the S wave in leads V1 to or V2 is >1
- ST elevation in the posterior leads on a posterior ECG (leads V7 to V9)
- Suspicion for a posterior MI must remain high, especially if inferior ST elevation is also present
5
Q
RV MI
A
- Can be seen after a proximal occlusion of the RCA
- ST elevation >1mm in lead V4
- ST elevation >1mm in lead V1 (sens. 70% spec 100%)
- Q waves II, III, aVF and ST elevation rV4
- V4 right is located at the same place as lead V4, but is placed on the right side of the pt. This means it is placed under the right nipple instead of the left. This increases the sensitivity of deteting right ventricle infarcts.
6
Q
Serum Markers of a MI
A
Cardiac Enzymes
- Troponins
- CPK
- CK-MB
7
Q
Troponin as a MI Marker
A
- Can take upwards of 6-12hrs for troponins to show up in the blood stream
- Prolonged elevation for 7-10days before returning to baseline
*trops are less useful in detecting recurrent infarctions during this time
- Rise in serum Trop 1 or T is considered diagnostic for AMI
- Low level elevations in Trop correlate w/ risk for CV complications in UA, CAD and renal failure
8
Q
CK-MB as a MI Marker
A
- A serial rise to above 5 times baseline followed by a fall back to baseline is considered diagnostic for AMI
- Peaks at 12-24hrs, with fall back to baseline in 2-3days
- Useful in detecting recurrent infarction after the initial 24-48hrs by noting a repeat elevation in the level
9
Q
Myoglobin as a MI Marker
A
- Rises within 2-3hrs of symptoms onset
- Peaks within 4-24hrs
- More sensitive than CK and CK-MB but NOT specific for cardiac muscle
- There is a high false-pos. rate due to its presence in all muscle tissue
10
Q
Treatment of Acute Coronary Syndrome Chart
A
11
Q
Treatment of Acute Coronary Syndromes Step-wise Chart
A
12
Q
Beta Blockers as MI treatment
A
- Give PO, can use IV if active CP then use orally unless contraindication exists
*hypotension, significant bradycardia, asthma (relative CI)
Decreases:
- Sympathetic drive; HR and BP
- O2 demand
- Shear stress
- Sudden death
- Recurrent MI
- Risk arrhythmia, reinfarction, rupture, death
13
Q
Nitrates as MI Treatment
A
- Reduce pain/ischemia
- Relieves pain
- Reduce pulmonary congestion in heart failure
- Only use IV w/ frequently recurring CP, for ischemia assoc. w/HTN, or CHF
- Reduce ischemia (not mortality)
- Venodilation: decrease R heart return
- Coronary vasodilation
14
Q
ACE Inhibitors as MI Treatment
A
- Limit adverse LV remodeling
- Heart failure/death decreased
- MI decreased
- Benefit additive aspiring, beta-blockers
- Esp. benefit anterior MI and/or LV dysfunction
- Short acting captopril 6.25mg PO TID to be doubled w/ each subsequent dosing up until 50mg PO TID or Lisinopril 5mg PO q day w/ uptitration to 20-40mg day
15
Q
Statins as a MI Treatment
A
- Reduce reinfarction, death
- More benefit when started early
- Give regardless of LDL
- Ideal LDL goal should be <70 but really as low as possible
- CRESTOR 20, LIPITOR 40-80mg, Zocor 20-40
