TIMI Risk Score Calculator for STEMI (30-day mortality, Morrow 2000)

Understanding the TIMI risk score for STEMI — concept and principle

The TIMI risk score for ST-elevation myocardial infarction (STEMI) estimates 30-day mortality from eight simple features available at the bedside. It was developed by Morrow and colleagues (2000) in patients treated with fibrinolytic therapy and is used to rank risk quickly.

Points from the history: with the default inputs the result is 4 → 7.3% (30-day mortality).

How it is calculated

TIMI STEMI score (0–14):

Age 65–74: 2; 75 or older: 3
Diabetes, hypertension or angina: 1
Systolic BP under 100 mmHg: 3
Heart rate over 100: 2
Killip class II–IV: 2
Weight under 67 kg: 1
Anterior ST elevation or left bundle branch block: 1
Time to treatment over 4 hours: 1

30-day mortality by score: 0 0.8%, 1 1.6%, 2 2.2%, 3 4.4%, 4 7.3%, 5 12%, 6 16%, 7 23%, 8 27%, 9 or more 36%.

The principle

The score was derived from the InTIME II trial. Age, low blood pressure, fast heart rate and heart failure signs (Killip class) reflect how much heart muscle is affected and how well the circulation copes; anterior infarcts involve more muscle; low weight and delayed treatment add risk. Points were weighted by each factor's strength.

Worked example

Default inputs: age 65–74, diabetes/hypertension/angina yes, anterior ST elevation yes; all other items no.

Age 65–74 = 2.
History of diabetes, hypertension or angina = 1.
Anterior ST elevation = 1.
Total 4 → 30-day mortality in the study 7.3%.

How to read the result

Higher scores identify patients who need closer monitoring and intensive care. Most patients today have primary angioplasty, so absolute rates may be lower than in the original data, but the ranking of risk still holds. The score never delays reperfusion.

Common mistakes

Counting age 65 in the 75+ band or vice versa.
Forgetting the weight item.
Using the STEMI score for NSTEMI, which has its own TIMI score.

Keep in mind: This is a classification aid for clinicians, not a diagnosis. Chest pain needs emergency care; call your local emergency number.

Frequently asked questions

What is Killip class?

A bedside grading of heart failure in heart attack: I none, II crackles or third heart sound, III pulmonary oedema, IV cardiogenic shock.

Is a score of 4 high?

It corresponds to intermediate risk, with 7.3% 30-day mortality in the study.

Is there a better score?

GRACE is widely used for all acute coronary syndromes; TIMI is simpler.

Sources: Morrow DA, Antman EM, Charlesworth A, et al., "TIMI risk score for ST-elevation myocardial infarction: a convenient, bedside, clinical score for risk assessment at presentation", Circulation 2000;102(17):2031–2037

Checked 9 Nov 2026. Morrow DA, Antman EM, Charlesworth A, et al., “TIMI risk score for ST-elevation myocardial infarction: a convenient, bedside, clinical score for risk assessment at presentation”, Circulation 2000;102(17):2031–2037 — points and 30-day mortality as given in the MSD Manual Professional calculator “TIMI Score for ST Elevation Acute Myocardial Infarction”.

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