The most serious type of ischemic injury is acute myocardial infarction (AMI). Transient and fully reversible myocardial ischemia is called angina pectoris . Clinical manifestations:
Classical tests in the diagnosis of MI[edit | edit source]
| Test enzyme |
Standard |
The beginning of the rise |
Maximum |
Standardization |
Multipler at maximum
|
| Aspartate aminotransferase (AST) |
< 0,67 μkat/l |
4–8 h |
16–48 h |
3–6 days |
Up to 25
|
| Creatine kinase (CK) |
men < 3,2 μkat/l
|
3–6 h |
16–36 h |
3–5 days |
Up to 25
|
| women < 2,4 μkat/l
|
| CK-MB isoenzyme |
< 0,4 μkat/l, < 6 % of total CK activity |
|
|
|
|
| Lactate dehydrogenase(LD) |
< 8 μkat/l |
6–12 h |
24–60 h |
7–15 days |
Up to 8
|
| LD isoenzymes |
|
|
|
|
|
New tests in the diagnosis of MI[edit | edit source]
Myoglobin, CK MB mass and Troponin, their serum levels during myocardial ischemia
- Myoglobin
- cytoplasmic protein, source of O2 in the anaerobic phase of contraction
- in the blood 0.5-2 h after MI (sensitivity 4-5 h)
- small molecule (Mr = 17,100), rapidly lost from the blood through the glomeruli
- standard
- CK-MB mass isoenzyme (antigen determination)
- concentration is given in mass units (µg/l) !!
- degraded molecules also react to the antigen (higher sensitivity)
- standard: < 5 µg/l
| Test enzyme |
The beginning of the rise |
Maximum |
Standardization |
Multiplier at maximum
|
| Myoglobin |
0,5–2 h |
6–12 h |
0,5–1 d |
Up to 20
|
| Troponin T |
3,5–10 h |
12–18 h (3–4 d) |
7–20 d |
Up to 300
|
Recommended procedure for biochemical examination in suspected AMI[edit | edit source]
- First recruitment on admission - STATIM
- Basic parameters for broader differential diagnosis: Na, K, Cl, urea, creatinine, Ca, uric acid, cholesterol, TAG, total bilirubin, ALT, AST, ALP, GMT, LD, CRP
- Cardiac markers:
- CK, CK-MB
- Myoglobin – difficulties lasting 2-12 hours, normal renal function
- Troponin T:
- a) within 8 hours to exclude AMI
- b) after 12 hours to diagnose microinfarcts
- Further recruitment
- 2. Recruitment in 6 ± 2 hours (CK, CK-MB, troponin T, Myoglobin)
- 3. Recruitment in 12 ± 2 hours (CK, CK-MB if the diagnosis or extent of involvement is not clear)
- 4. Recruitment in 24 ± 2 hours - exceptionally
- normal in healthy, excludes AMI between 6 and 10 hour
- if the concentration rises to less than 40 µg/l within 1 h, MI can be ruled out
- excluding skeletal muscle damage, MI
- < 0.05 µg/l - MI can be excluded, repeat in 10-12 h
- 0.05-0.1 µg/l - it is recommended to repeat testing in 1 hour
- 0.1-3 µg/l - myocardial damage
- > 3 µg/l - massive myocardial damage
- <0.1 µg/l - MI can be excluded
- 0.6-1.5 µg/l - according to the WHO this is evidence of MI
Confirmation of myocardial reperfusion
| Analyze
|
Myocardial reperfusin
|
| Successful
|
Unsuccessful
|
| C1–C0 (µg/l) |
Tmax–T0(h) |
Tmax–T0(h)
|
| Myoglobin |
> 150 |
< 3 |
> 12
|
| CK MBmass |
> 10 |
< 8–12 |
> 12
|
| Troponin T |
> 0,2 |
< 14 |
> 14
|
| Troponin I |
> 100 |
< 14 |
> 14
|
- Hormones synthesized in atrial and ventricular cardiomyocytes
- Maintain electrolyte and volume homeostasis
- ANP, BNP - produced by cardiomyocytes
- CNP - produced by vascular endothelial cells and renal epithelium
