How this instrument works
Every one of the seven criteria here is worth exactly one point: age 65 or older; three or more standard risk factors for coronary artery disease; known coronary stenosis of 50 percent or more; aspirin taken within the preceding week; two or more anginal episodes in the last 24 hours; ST-segment deviation of half a millimetre or greater on the presenting ECG; and a cardiac biomarker — troponin or CK-MB — above the local reference range. None outranks another. A younger patient with no cardiac history who checks four of these boxes lands on the same 4 as an older patient with an entirely different combination of four.
Antman and colleagues built the instrument in 2000 from a pooled database of 7,081 patients drawn from the TIMI 11B and ESSENCE trials, then confirmed the pattern across three separate validation cohorts. Each of the seven variables predicted, on its own, the 14-day combined endpoint of death, a new or recurrent heart attack, or severe recurrent ischemia demanding urgent revascularization — and stacked together they sort patients cleanly: about 4.7 percent of those scoring 0 or 1 reach that endpoint within two weeks, against 40.9 percent of those scoring 6 or 7. Emergency physicians and cardiologists use the resulting figure to decide who needs an early invasive strategy — catheterization within a day or two — and who can be watched more conservatively.
Don't mistake this for the STEMI calculator elsewhere on this site, even though both carry the TIMI name. That version scores eight criteria on an uneven scale where age alone can add up to three points, while everything here stays flat at one point apiece across a 0-to-7 range. They aren't one formula recycled for two flavors of heart attack — Antman's team and Morrow's team drew on separate trial populations chasing separate outcome windows, so the two instruments genuinely reward different things.
- Mark Age 65 or older, then whether the patient has three or more standard CAD risk factors — family history, smoking, hypertension, diabetes, or high cholesterol.
- Mark Known CAD (prior stenosis of 50 percent or more) and Aspirin use in the preceding 7 days.
- Mark Severe angina — two or more episodes in the last 24 hours — and ST-segment deviation of 0.5 mm or more on the presenting ECG.
- Mark whether initial cardiac biomarkers sit above the local reference range.
- Read the total (0-7) alongside its associated 14-day risk band.
Worked example — five of seven criteria present
A 68-year-old with three or more coronary risk factors on record, no known coronary stenosis, aspirin taken four days earlier, no severe angina, fresh ST-segment deviation on the presenting ECG, and a troponin above the reference range. Tally it: age65 (1) + riskFactors3 (1) + knownCAD (0) + aspirin7d (1) + severeAngina (0) + stDeviation (1) + biomarkers (1) = 5.
A score of 5 sits in the 5-to-7 band. In the original derivation cohort that band carried a 14-day rate of death, MI, or urgent revascularization above 20 percent — 26.2 percent specifically at a score of 5, climbing to 40.9 percent at 6 or 7. That's the figure an emergency physician weighs against bleeding risk and comorbidities when deciding how fast to move toward catheterization.
Questions
What does a TIMI score of 0 or 1 actually mean?
It sits at the low end of the range this tool covers — about a 4.7 percent chance of death, a new or recurrent heart attack, or the need for urgent revascularization within 14 days, based on the original derivation cohort. Low doesn't mean zero, and a clinician still weighs the rest of the presentation, but it's the group least likely to need an immediate invasive workup on the score alone.
Why does recent aspirin use count against the patient?
Because someone already taking aspirin who still develops unstable angina or NSTEMI has broken through standard antiplatelet protection — that failure is itself a marker of a more aggressive underlying process, not a criticism of the medication. The point is added for having taken aspirin in the prior seven days, regardless of dose or reason.
Is this the same score used for a STEMI patient?
No. This site hosts a separate calculator for ST-elevation MI, and the two aren't interchangeable. This one weighs seven criteria equally over a 0-to-7 scale; the STEMI version gives age its own heavier weighting on top of seven flat one-point items. They were derived from different trial populations with different outcomes, so match the calculator to the presenting diagnosis.
What counts toward the 'three or more CAD risk factors' criterion?
The original study used five standard factors: a family history of coronary disease, current smoking, hypertension, diabetes, and high cholesterol. This item scores a point once three or more of those five are present; two present scores zero, the same as none present.
Does the score tell a clinician what treatment to give?
No — it stratifies risk, not therapy. It was built to inform urgency, chiefly whether an early invasive strategy or conservative management fits better, and it feeds a conversation about anticoagulation and catheterization timing. The actual treatment plan still folds in bleeding risk, comorbidities, and judgment the seven-item sum was never designed to capture.
How was the original score validated?
Antman's group derived it from 1,957 patients in the TIMI 11B trial, then confirmed the same climbing pattern across three further cohorts — a second TIMI 11B arm and two arms of the ESSENCE trial — for a combined 7,081 patients. Event rates rose in a consistent, stepwise fashion with the score in every cohort, which is what earned it broad clinical adoption.
References
- Antman EM, Cohen M, Bernink PJ, et al. — JAMA, 2000 (PubMed)
- American Heart Association — Acute Coronary Syndrome
Read this first: This instrument computes a screening figure from population formulas — it is not a diagnosis, and it cannot see the whole picture a clinician can. Use it to inform a conversation, not to replace one.