Prevalence
Clinical
features
Differential
diagnosis
Investigations
Therapy
Prevention
Prognosis
|  | | | Investigations |
Less helpful alternatives include
-
serial creatine kinase (CK)
b
c
, aspartate transaminase
(AST)
a
, lactate dehydrogenase
(LDH)
a
taken over 24 hours
a
Why?
-
96% of MI can be diagnose at 24 hours using CK-MB, LDH, CK and ECG changes
(95% CI: 95% to 98%)
a
Elevated creatine kinase levels diagnose myocardial infarction
| Patient |
Target Disorder and
Reference Standard |
Diagnostic Test |
LR+
(95% CI)
|
Post-test Probability |
|
suspected myocardial infarction
c
(pre-test probability: 64%)
|
myocardial infarction
(ECG changes)
|
highest CK 280 IU/ or more
|
54
(7.7 to
380)
|
99% |
|
|
|
CK 80 to 279 IU/l
|
4.5
(2.7 to
7.3)
|
89% |
|
|
|
CK 40 to 79 IU/l
|
0.30
(0.16 to
0.56)
|
35% |
|
|
|
CK < 40 IU/l
|
0.013
(0.0032 to
0.051)
|
2.0% |
Elevated AST levels taken 12 hours or more after symptom onset help diagnose myocardial infarction
| Patient |
Target Disorder and
Reference Standard |
Diagnostic Test |
LR+
(95% CI)
|
Post-test Probability |
central or left-sided chest pain
a
(pre-test probability: 41%)
|
myocardial infarction
(ECG, cardiac enzymes, stress tests)
|
AST taken more than 12 hours after chest pain onset:100 IU/l or more
|
30
|
89% |
|
|
|
80 IU/l
|
2.3
|
39% |
|
|
|
60 IU/l
|
5.6
|
60% |
|
|
|
50 IU/l
|
0.40
|
10% |
|
|
|
40 IU/l
|
0.59
|
14% |
|
|
|
30 IU/l
|
0.32
|
8% |
|
|
|
< 30 IU/l
|
0.078
|
2% |
-
CK
a
b
,
AST
a
or LDH
a
taken within 12 hours of symptom onset cannot safely exclude a myocardial infarction.
Cardiac enzymes taken in the emergency department cannot diagnose or exclude a myocardial infarction
| Patient |
Target Disorder and
Reference Standard |
Diagnostic Test |
LR+
(95% CI)
|
Post-test Probability |
LR-
(95% CI)
|
Post-test Probability |
central or left-sided chest pain
a
(pre-test probability: 17%)
|
myocardial infarction
(ECG, cardiac enzymes)
|
CK > 180
|
1.8
(1.3 to
2.5)
|
27% |
0.77
(0.65 to
0.91)
|
14% |
|
|
|
AST > 60
|
6.1
(3.5 to
10)
|
56% |
0.43
(0.29 to
0.64)
|
8% |
|
|
|
AST > 47
|
3.4
(2.3 to
5.1)
|
41% |
0.44
(0.29 to
0.68)
|
8% |
|
|
|
LDH > 200
|
2.0
(- to
-)
|
29% |
0.59
(- to
-)
|
11% |
|
|
|
CK or AST abnormal
|
1.7
(1.3 to
2.2)
|
26% |
0.65
(0.51 to
0.82)
|
12% |
CK levels alone taken at 24 hours cannot safely diagnose or exclude myocardial infarction
| Patient |
Target Disorder and
Reference Standard |
Diagnostic Test |
LR+
(95% CI)
|
Post-test Probability |
LR-
(95% CI)
|
Post-test Probability |
|
central or left-sided chest pain
b
(pre-test probability: 18%)
|
myocardial infarction
(CK-MB at 24 hours)
|
elevated creatine kinase
|
6.0
(3.7 to
9.8)
|
57% |
0.62
(0.50 to
0.76)
|
12% |
|
internal medicine