TIMI Score for STEMI Calculator
Calculate 30-day mortality risk in ST-elevation myocardial infarction using the validated TIMI STEMI score based on clinical and hemodynamic parameters.
Enter age, vital signs, Killip class, weight, and clinical features. The calculator applies the validated TIMI Risk Score formula for STEMI to estimate 30-day mortality.
TIMI Score for STEMI Calculator
Calculate 30-day mortality risk in ST-elevation myocardial infarction using the validated TIMI STEMI score based on clinical and hemodynamic parameters.
About the TIMI Score for STEMI
The TIMI Risk Score for ST-Elevation Myocardial Infarction (STEMI) is a validated clinical prognostic tool that estimates the probability of 30-day all-cause mortality following an acute STEMI. Developed by Morrow and colleagues and published in 2000 using data from the InTIME II trial involving more than 14,000 patients, the score has been validated across multiple independent STEMI populations worldwide and remains a cornerstone of risk stratification in the acute cardiac care setting.
The TIMI STEMI score incorporates nine clinical variables that are readily available at the time of hospital presentation. Age carries the most weight: patients aged 65–74 receive 2 points, while those aged 75 or older receive 3 points, reflecting the dramatically higher mortality in elderly STEMI patients. Systolic blood pressure below 100 mmHg contributes 3 points, capturing hemodynamic compromise as a powerful mortality predictor. Heart rate above 100 beats per minute adds 2 points. Killip class II through IV (indicating any degree of heart failure or cardiogenic shock) adds 2 points. Weight below 67 kilograms adds 1 point. Anterior ST elevation or the presence of left bundle branch block on ECG contributes 1 point. A history of diabetes mellitus, hypertension, or prior angina contributes 1 point. Finally, time to treatment longer than 4 hours contributes 1 point. The maximum possible score is 14.
Observed 30-day mortality rates from the InTIME II data increase steeply with score: approximately 0.8% at score 0, 1.6% at score 1, 2.2% at score 2, 4.4% at score 3, 7.3% at score 4, 12.4% at score 5, 16.1% at score 6, 23.4% at score 7, 26.8% at score 8, and approximately 35.9% at scores of 9 or higher. This steep gradient makes the score valuable for identifying very low-risk patients who may be candidates for less intensive pathways and very high-risk patients who require the highest level of care.
Clinically, the score guides a wide range of management decisions. Low-risk patients (score 0–3) generally have good outcomes with standard STEMI protocols. Moderate-risk patients (score 4–6) benefit from close monitoring and consideration of advanced therapies. High-risk and very-high-risk patients (score 7 and above) may require intensive care unit admission, mechanical circulatory support, and aggressive pharmacological therapy. The score also helps with family counseling and shared decision-making about treatment options and expected prognosis.
The TIMI STEMI score should be used alongside—not instead of—clinical assessment. Some variables such as precise weight measurement may not be available under emergency conditions, and the score may be less reliable in certain populations. Always integrate the score with imaging findings, electrocardiographic evolution, biomarker trends, and the treating team's clinical judgment. This tool is intended for educational and clinical decision support only.
TIMI STEMI score examples
These examples show how patient characteristics map to TIMI scores and estimated 30-day mortality rates.
| Patient Profile | TIMI Score | 30-Day Mortality |
|---|---|---|
| Age 45, SBP 140 mmHg, HR 75 bpm, Killip I, weight 70 kg, no DM/HTN, no anterior STE, presentation at 2 h | Score 0 | ~0.8% — Very low risk; standard STEMI protocol with routine follow-up. |
| Age 70, SBP 105 mmHg, HR 90 bpm, Killip II, weight 75 kg, yes DM, no anterior STE, presentation at 5 h | Score 6 | ~16.1% — Moderate-to-high risk; intensive monitoring and consider advanced therapies. |
| Age 78, SBP 85 mmHg, HR 120 bpm, Killip IV, weight 60 kg, yes DM, anterior STE + LBBB, presentation at 8 h | Score 14 | ~35.9% — Very high risk; ICU admission, mechanical support consideration, specialized care. |
How to use the TIMI STEMI calculator
- Record the patient's age, systolic blood pressure, and heart rate from the initial assessment.
- Determine the Killip class based on the presence and severity of heart failure signs at presentation.
- Enter the patient's weight (in kg) and note whether the presenting ECG shows anterior ST elevation or left bundle branch block.
- Indicate whether the patient has a history of diabetes mellitus, hypertension, or prior angina, and record the time from symptom onset to anticipated treatment.
- Click Calculate TIMI STEMI Score to view the total score (0–14), the estimated 30-day mortality percentage, and the risk category for treatment guidance.
TIMI STEMI calculator FAQ
What does the TIMI STEMI score predict?
The TIMI STEMI score estimates the probability of all-cause mortality at 30 days following an acute ST-elevation myocardial infarction. It was derived from InTIME II trial data and validated in multiple independent STEMI cohorts representing diverse patient populations and treatment strategies.
Why does weight below 67 kg increase the score?
Low body weight was identified as an independent predictor of mortality in the original analysis, likely reflecting lower physiological reserve, greater susceptibility to hemodynamic compromise, and higher relative drug doses. It is not a marker of malnutrition per se but a statistical predictor of worse outcomes in STEMI patients.
What is the Killip classification?
The Killip classification describes the degree of heart failure at presentation. Class I means no clinical signs of heart failure. Class II indicates mild failure with an S3 gallop or crackles in the lung bases. Class III indicates frank pulmonary edema. Class IV indicates cardiogenic shock with hypotension and evidence of peripheral hypoperfusion. Classes II through IV each add 2 points to the TIMI STEMI score.
Is the TIMI STEMI score applicable to all STEMI patients?
The score was derived from a thrombolytic-era trial and has been validated in both thrombolytic and primary PCI populations. It remains predictive across different treatment strategies. However, it was not designed for patients with prior CABG, those with rare presentations, or specific high-complexity subgroups, so use clinical judgment in atypical cases.
How does the TIMI STEMI score differ from the GRACE score for STEMI?
The GRACE score provides continuous risk estimates using a more complex algorithm and is well validated across the full spectrum of ACS including both STEMI and NSTEMI. The TIMI STEMI score is simpler and faster to calculate, making it practical under time pressure. Both tools provide complementary information and can be used together for comprehensive risk assessment.
What is the time-to-treatment threshold used in this score?
Treatment delay of more than 4 hours from symptom onset to reperfusion adds 1 point to the TIMI STEMI score. This reflects the well-established time-is-myocardium principle; every minute of delay increases myocardial damage and mortality risk. Rapid door-to-balloon or door-to-needle times remain critical quality metrics in STEMI care.