Cardiac Markers

Cardiac markers
Marker	Initial Elevation	Peak Elevation	Return to Baseline
Myoglobin	1-4 h	6-7 h	18-24 h
CK-MB	4-12 h	10-24 h	48-72 h
Cardiac Trop I	3-12 h	10-24 h	3-10 d
Cardiac Trop T	3-12 h	12-48 h	5-14 d

The troponin I is the most sensitive cardiac marker, detectable in serum 3-6 hours after an MI, and its level remains elevated for 14 days.

Anterior Wall MI

Anterior wall infarction results from occlusion of the proximal LAD artery. ST-segment elevation is expected in leads V1 through V4 on the 12-lead ECG, as shown in. If the left main coronary artery is occluded, the ECG manifestations will involve almost all of the precordial leads V1through V6 and leads I and aVL (see above). These specific groups of ECG changes that help to locate the part of the heart that is infarcting are called indicative changes. A large anterior wall MI may be associated with left ventricular pump failure, cardiogenic shock, or death.

LATERAL WALL INFARCT

Left lateral wall infarction occurs as a result of occlusion of the circumflex coronary artery. On a 12-lead ECG, new Q waves and ST-segment T-wave changes are seen in leads I, aVL, V5, and V6.  In reality, very few patients present with only lateral wall ECG changes. Often times some anterior wall leads (V3 and V4) may show evidence of injury or infarction. 

ANSWERS #1-20

1.  A - Nipride

2.  A - PVR
3.  A - Pulmonary Edema
4.  A - RAP
5.  C - Pulmonary HTN
6.  C - Vasoconstriction
7.  A - Increased HR, contractility, conductivity
8.  D - Vasodilation, bronchodilation
9.  B - Dilation of the renal and mesenteric arteries
10. D - Phenylephrine
11. C - Dobutamine
12. A - Isoproternol
13. B - Dopamine at 2 mcg
14. B - V3
15. D - Phenylephrine
16. C - Start large bore IVs, get lab samples and fluid bolus
17. C - Pericardial tamponade
18. D - Perform synchronized cardioversion
19. C - Atrial fib
20. C -Bleeding at the groin site


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CLINICAL TRIAD OF RIGHT VENTRICULAR INFARCT (RVI)

1.  Hypotension

2.  Jugular Vein Distension

3.  Dry Lung Sounds

Inferior Wall MI R/T Right Ventricular Infarct

CLINICAL PEARL: 


If your patient is admitted with an Inferior wall MI always obtain a right sided EKG. 45% of patients that present with Inferior Wall MI will also develop Right Ventricular Infarct (RVI). See image below for placement of electrodes for right sided EKG.


This is important because the treatment is different for RVI.