Free TIMI Score for STEMI Calculator
Select the patient's age and check all applicable criteria to calculate the TIMI Score and 30-day mortality risk.
Age • History • Vital Signs • ECG • Treatment
The TIMI (Thrombolysis In Myocardial Infarction) risk score for STEMI is a validated bedside tool used to stratify patients with ST‑segment elevation myocardial infarction according to their 30‑day mortality risk. Originally developed by Morrow and colleagues in 2000, this cardiac risk assessment tool relies on eight clinical parameters, with the Killip class serving as a particularly strong predictor of fatal outcomes. This free online TIMI STEMI risk calculator enables clinicians to quickly obtain a mortality risk estimate without needing to memorize point values.
Development and Clinical Use of the TIMI STEMI Score
The TIMI risk score for STEMI was derived from clinical trial data and has since been validated in numerous independent populations. Its ease of use and robust prognostic performance have made it a standard component of acute myocardial infarction management. The score is intended for patients with confirmed STEMI (not for unstable angina or NSTEMI) and provides a probability of death within 30 days, helping clinicians decide on the intensity of monitoring and treatment.
Components of the TIMI STEMI Risk Score
The score consists of eight criteria, each weighted based on logistic regression analysis. The following list describes each component:
- Age: ≥65 years receives 2 points; ≥75 years receives 3 points. Age is a non‑modifiable risk factor.
- Diabetes, angina, or hypertension: Any of these conditions contributes 1 point, as they are well‑known risk factors for coronary artery disease.
- Heart rate >100 bpm: A resting tachycardia (2 points) often signals cardiac decompensation.
- Killip class II–IV: Clinical signs of heart failure (rales, S3 gallop, elevated jugular venous pressure, pulmonary edema, or cardiogenic shock) earn 2 points.
- Systolic blood pressure <100 mmHg: Hypotension (3 points) reflects poor hemodynamic status.
- Anterior ST‑segment elevation or LBBB: This ECG finding (1 point) indicates anterior involvement; for LBBB, the Sgarbossa criteria may be used to confirm ST‑elevation equivalence.
- Time to treatment >4 hours: Delayed reperfusion (1 point) increases mortality risk.
- Body weight <150 lb (≈67 kg): Lower weight (1 point) has been associated with higher fatality.
The total score ranges from 0 to 14, with higher values corresponding to a greater risk of 30‑day mortality.
Killip Classification – A Key Component
Among the criteria, the Killip class deserves special attention because it is the strongest single predictor. This physical‑examination‑based classification (first described in 1967) remains valid today.
| Killip class | Clinical findings | 30‑day mortality |
|---|---|---|
| I | No signs of heart failure | 2–3 % |
| II | Rales, S3 gallop, elevated JVP | 5–12 % |
| III | Acute pulmonary edema | 10–20 % |
| IV | Cardiogenic shock (hypotension, oliguria, diaphoresis, cyanosis) | 10–20 % |
In the TIMI score, classes II, III, and IV contribute 2 points to the total.
Using the Online TIMI STEMI Risk Calculator
The calculator offers a streamlined workflow: select the patient’s age range from a drop‑down menu, then toggle the presence of each risk factor. Built‑in tooltips provide guidance on each criterion, including a dedicated Killip class selector. The total score and the associated 30‑day mortality estimate are displayed as soon as all fields are completed. This tool is designed for use in emergency departments, chest pain units, and cath labs to support rapid risk stratification.
Important Caveats
While the TIMI score for STEMI is a valuable aid, it should always be used in conjunction with clinical judgment. The calculator cannot replace a comprehensive physician assessment. Moreover, the score is validated only for STEMI patients in the acute setting; it is not appropriate for long‑term risk prediction in stable individuals. For cardiovascular risk assessment over longer horizons, tools such as the Framingham or ASCVD risk score may be more suitable.
FAQ
1. How is the TIMI STEMI risk score calculated?
The TIMI STEMI risk score is calculated by summing points assigned to eight criteria: age (2 or 3 points), diabetes/angina/hypertension (1 point), heart rate >100 bpm (2 points), Killip class II–IV (2 points), systolic BP <100 mmHg (3 points), anterior ST elevation or LBBB (1 point), time to treatment >4 hours (1 point), and weight <150 lb (1 point). The total score ranges from 0 to 14, with higher scores reflecting greater 30‑day mortality risk.
2. What is the Killip class and why does it matter in the TIMI STEMI score?
The Killip class is a physical‑examination‑based grading of heart failure severity in acute myocardial infarction (I = no failure, II = rales/ S3 gallop, III = pulmonary edema, IV = cardiogenic shock). In the TIMI STEMI score, classes II–IV contribute 2 points because they are strong independent predictors of early mortality.
3. Can the TIMI STEMI score be used for patients with unstable angina or non‑STEMI?
No. The TIMI STEMI score was specifically developed for patients with ST‑elevation myocardial infarction. For unstable angina or non‑STEMI, a separate TIMI risk score (the UA/NSTEMI TIMI score) should be applied.
4. Is the online TIMI STEMI risk calculator free to use?
Yes, this calculator is available online at no cost. It provides rapid risk stratification for healthcare professionals and does not require registration or payment.
How to Use
- Select the patient's age group from the dropdown and check all clinical criteria that apply: medical history (diabetes, hypertension, angina), vital signs (heart rate >100 bpm, systolic BP <100 mmHg), Killip class II-IV, ECG findings (anterior ST elevation or LBBB), time to treatment >4 hours, and weight <67 kg.
- The tool automatically calculates the total TIMI score (range 0-14) and displays the corresponding 30-day all-cause mortality risk based on the validated Morrow et al. risk stratification model.
- Review the risk category and mortality percentage to guide clinical decisions - low-risk patients (score 0-3) may be managed with standard care, while high-risk patients (score 7+) may require intensive monitoring and aggressive intervention.