What does the TIMI STEMI score predict?

The TIMI Risk Score for STEMI predicts 30-day all-cause mortality in patients presenting with ST-elevation myocardial infarction. It was derived from the InTIME II thrombolytic trial and has been validated in multiple independent STEMI cohorts.

How is the TIMI STEMI score different from the TIMI NSTEMI score?

The two scores use completely different criteria and predict different outcomes. The STEMI score predicts 30-day mortality and uses weighted criteria (not all worth 1 point). The NSTEMI/UA score uses 7 equally weighted criteria and predicts 14-day composite cardiovascular events. They should not be used interchangeably.

What is the Killip classification used in this score?

The Killip classification grades heart failure severity in acute MI: Class I = no heart failure signs; Class II = mild failure (bibasilar rales, S3); Class III = pulmonary edema; Class IV = cardiogenic shock. Killip class II or higher contributes points to the TIMI STEMI score.

What counts as an anterior ST elevation or LBBB?

Anterior ST elevation refers to new ST elevation in leads V1-V4. Left bundle branch block (LBBB) can mask ischemic changes and is treated as a STEMI equivalent in this scoring context. Either finding contributes 1 point under the ECG domain.

What is a high-risk infarct location?

For the TIMI STEMI score, high-risk location refers to anterior MI (ST elevation in V1-V4) or ST elevation in the lateral leads suggesting large territory at risk. Inferior MIs without right ventricular involvement are generally considered lower risk.

Is this score applicable after primary PCI?

The original TIMI STEMI score was derived in a thrombolytic therapy trial. It has been studied in PCI populations and retains discriminatory value, but absolute mortality rates may differ from the original trial cohort due to differences in reperfusion strategy, adjunctive therapy, and patient selection. Use clinical judgment alongside the score.

Is this tool a replacement for clinical judgment?

No. The TIMI STEMI score is a decision support aid and must be interpreted alongside the full clinical picture, time-to-treatment, institutional capabilities, patient comorbidities, and current ACC/AHA guidelines. It is not a substitute for experienced clinical judgment or a standalone basis for treatment decisions.

TIMI Score for STEMI

Name: TIMI Score for STEMI
Availability: InStock
Author: Nham Vu

Select the TIMI STEMI criteria to calculate the risk score and estimate 30-day all-cause mortality after ST-elevation myocardial infarction.

TIMI STEMI Criteria

History

Age ≥ 75 years

Patient is 75 years of age or older at time of presentation

Age 65 – 74 years

Patient is between 65 and 74 years of age — select this OR the ≥75 criterion, not both

Diabetes mellitus, hypertension, or angina

Known diagnosis of diabetes, hypertension, or prior angina pectoris

Examination

Systolic BP < 100 mmHg

Presenting systolic blood pressure below 100 mmHg indicating hemodynamic compromise

Heart rate > 100 bpm

Presenting heart rate above 100 beats per minute at initial assessment

Killip class II – IV

Clinical evidence of heart failure: rales, S3 gallop, pulmonary edema, or cardiogenic shock (Killip II, III, or IV)

Weight < 67 kg (147.7 lb)

Presenting body weight below 67 kilograms — lower body mass associated with higher relative risk

ECG & Presentation

Anterior ST elevation or LBBB

ST elevation in leads V1-V4 indicating anterior MI, or new left bundle branch block (STEMI equivalent)

Time to treatment > 4 hours

More than 4 hours from symptom onset to first reperfusion therapy (thrombolysis or PCI)

TIMI STEMI Score

0 / 14

Low Risk

30-day mortality: ~0.8%

Score progress (0-14)

Clinical Interpretation

A score of 0 represents the lowest risk profile. Proceed with standard reperfusion therapy. Serial monitoring and supportive care are appropriate.

Risk Reference Table

Score	Risk Tier	30-Day Mortality
0	Low	0.8%
1	Low	1.6%
2	Low	2.2%
3	Low	4.4%
4	Moderate	7.3%
5	Moderate	12.4%
6	Moderate	16.1%
7	High	23.4%
8	High	26.8%
9	High	35.9%
10+	Very High	≥41%

30-day all-cause mortality rates from the InTIME II trial (Morrow et al., JAMA 2000). Rates reflect thrombolytic-era data; PCI-era mortality may differ.

Medical Disclaimer: This tool is for educational and clinical decision support only. It does not constitute medical advice and must not be used as the sole basis for treatment decisions. Always apply clinical judgment, follow current ACC/AHA guidelines, and involve qualified healthcare professionals in all patient care decisions.

Summary

Select the TIMI STEMI criteria to calculate the risk score and estimate 30-day all-cause mortality after ST-elevation myocardial infarction.

How it works

Review the three criterion groups: History, Examination, and ECG findings.
Check each criterion that applies to the patient at presentation.
Each criterion carries a specific point weight (not all are equal); the tool adds them automatically.
The result panel on the right updates instantly with the total score, risk tier, and estimated 30-day mortality.
Use the reference table to compare the patient's score against published mortality rates.
Click "Reset" to clear all selections for a new patient.

Use cases

Emergency department and cath lab risk stratification for STEMI patients presenting for reperfusion therapy.
Cardiology triage to prioritize higher-risk patients for early escalation or transfer to a PCI-capable center.
Clinical communication tool to discuss estimated 30-day mortality risk with patients and families.
Medical education and exam preparation for USMLE, cardiology boards, and emergency medicine training.
Quality improvement and ACS protocol development in hospitals managing STEMI.
Research and audit to compare observed versus predicted mortality in STEMI cohorts.

Frequently Asked Questions

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Last updated: 2026-05-23 · Reviewed by Nham Vu