Madsen et al developed a risk calculation in 1983 to determine the probability of an adverse cardiac event occurring for a patient with a recent myocardial infarct. At that time patients with myocardial infarcts were hospitalized for relatively long periods. It was felt that patients at low risk for an adverse cardiac event could be discharged earlier. Patients may be evaluated from day 5 to 30 after the infarct, with the endpoint being the probability of an adverse cardiac event in the next 2 weeks.
Parameters studied using a Cox regression model:
(1) age
(2) history of previous myocardial infarction
(3) heart failure
(4) ventricular fibrillation
(5) asystole
(6) supraventricular tachycardia
(7) premature ventricular beats
(8) nodal rhythm
(9) extension of the myocardial infarct
|
Parameter |
Finding |
Points |
|---|---|---|
|
age in years |
|
(age) |
|
history of previous myocardial infarction |
present |
1 |
|
|
absent |
0 |
|
heart failure |
present |
1 |
|
|
absent |
0 |
|
ventricular fibrillation |
present |
1 |
|
|
absent |
0 |
|
asystole, with or without ventricular fibrillation |
present |
1 |
|
|
absent |
0 |
|
supraventricular tachycardia |
present |
1 |
|
|
absent |
0 |
|
premature ventricular beats |
present |
1 |
|
|
absent |
0 |
|
nodal rhythm |
present |
1 |
|
|
absent |
0 |
|
extension of myocardial infarct |
present |
1 |
|
|
absent |
0 |
score for cardiac arrest endpoint =
= (0.010 * (points for age)) + (2.2 * (points for heart failure)) + (points for supraventricular tachycardia) + (0.9 * (points for premature ventricular beats)) + (points for extension of MI) - 0.6
score for death endpoint =
= (0.082 * (points for age)) + (2.3 * (points for heart failure)) + (2.7 * (points for ventricular fibrillation)) + (3.4 * (points for asystole)) - 4.9
score for cardiogenic shock endpoint =
= (0.028 * (points for age)) + (0.22 * (points for previous MI)) + (3.3 * (points for heart failure)) + (1.2 * (points for ventricular fibrillation)) + (1.2 * (points for asystole)) + (0.8 * (points for nodal rhythm)) - 1.7
X =
= ((hazard for cardiac arrest on starting date) * EXP(score for cardiac arrest)) + ((hazard for death on starting date) * EXP(score for death)) + ((hazard for cardiogenic on starting date) * EXP(score for cardiogenic shock))
risk of an adverse cardiac event within 14 days =
= 1 - EXP((-1) * (X))
|
day |
hazard for cardiac arrest |
hazard for death |
hazard for cardiogenic shock |
|---|---|---|---|
|
5 |
0.00687 |
0.00142 |
0.001 |
|
6 |
0.00656 |
0.00133 |
0.00089 |
|
7 |
0.00595 |
0.0012 |
0.00075 |
|
8 |
0.00518 |
0.0011 |
0.00062 |
|
9 |
0.00433 |
0.00089 |
0.00059 |
|
10 |
0.00439 |
0.0008 |
0.00053 |
|
11 |
0.00423 |
0.00075 |
0.00052 |
|
12 |
0.0041 |
0.00084 |
0.00043 |
|
13 |
0.00338 |
0.00092 |
0.00044 |
|
14 |
0.00331 |
0.00095 |
0.00041 |
|
15 |
0.00325 |
0.00092 |
0.0004 |
|
16 |
0.00284 |
0.00085 |
0.00033 |
|
17 |
0.00216 |
0.00074 |
0.0003 |
|
18 |
0.00187 |
0.00074 |
0.00033 |
|
19 |
0.00141 |
0.00057 |
0.0003 |
|
20 |
0.00136 |
0.00057 |
0.0003 |
|
21 |
0.00136 |
0.00057 |
0.00026 |
|
22 |
0.00136 |
0.00052 |
0.00026 |
|
23 |
0.00136 |
0.00054 |
0.00021 |
|
24 |
0.00107 |
0.00054 |
0.00021 |
|
25 |
0.001 |
0.00057 |
0.00021 |
|
26 |
0.00134 |
0.00066 |
0.00021 |
|
27 |
0.00151 |
0.00072 |
0.00021 |
|
28 |
0.00154 |
0.0007 |
0.00021 |
|
29 |
0.00141 |
0.00056 |
0.00021 |
|
30 |
0.00154 |
0.00059 |
0.00021 |
(data from Figure 1, page 12)
Interpretation:
• If the risk of an adverse cardiac event was less than 2%, then the authors felt the patient could be discharged.
Limitation:
• The score was formulated in 1983, before many advances in the diagnosis and management of myocardial infarction. However, the risk estimate may be useful in areas where the newest techniques are not available.
Specialty: Cardiology
ICD-10: ,
