Patients presenting to the Emergency Department with acute chest pain can be stratified into risk groups for acute myocardial infarction based on their clinical and electrocardiographic (ECG) findings. This can help determine the level of medical care appropriate for the patient. The criteria are a result of the Multicenter Chest Pain Study.
Criteria for risk categories:
(1) high risk
(1a) suspected MI on ECG, OR
(1b) suspected ischemia on ECG, with 2 or more risk factors
(2) moderate risk
(2a) suspected ischemia on ECG, with 0-1 risk factor OR
(2b) MI and ischemia not suspected on ECG, but 2 or more risk factors
(3) low risk
(3a) MI and ischemia not suspected on ECG, but 1 risk factor
(4) very low risk
(4a) MI and ischemia not suspected on ECG, and no risk factors
Myocardial infarction suspected:
(1) ECG shows (a) ST-segment elevation of 1 mm or more, or (b) pathologic Q waves, in 2 or more leads
(2) these findings were not known to be old
Ischemia suspected :
(1) ECG shows (a) ST-segment depression of 1 mm or more, OR (b) T wave inversion, in 2 or more leads
(2) these findings were not known to be old
Risk factors:
(1) systolic blood pressure < 110 mm Hg
(2) rales heard above the bases bilaterally on physical examination
(3) known unstable ischemic heart disease: one or more of the following
(3a) worsening of previously stable angina
(3b) new onset of postinfarction angina
(3c) angina after coronary revascularlization procedure
(3d) pain that is the same as that associated with a prior myocardial infarction
|
Risk Group
|
Risk of Major Ischemic Event in Time Period
|
|
|
<= 12 hours
|
12-24 hours
|
0-72 hours
|
|
high
|
7.6-12.1%
|
3.4-4.0%
|
16.1-21.5%
|
|
moderate
|
1.1-2.8%
|
1.9-2.2%
|
7.8-8.1%
|
|
low
|
0.5-0.7%
|
0.9-1.2%
|
3.6-3.9%
|
|
very low
|
0.1-0.2%
|
0.2%
|
0.6-0.8%
|
after Table 4, page 1502, combining derivation and validation set data
