Figure 3.

Proposed 1-hour algorithm. This is a new 1-hour algorithm for the evaluation of patients with suspected acute coronary syndrome (modified from [4]). With the aid of highly sensitive cardiac troponin (hs-cTn) assays, patients admitted to the emergency room with a suspected non-ST-elevation myocardial infarction (NSTEMI) can be evaluated within 1 hour of arrival.

The time points 0 hr and 1 hr are in relation to the first blood drawing upon admission.

“Rule out”: an NSTEMI can be ruled out if the hs-cTn levels are very low on admission, or if the baseline levels of hs-cTn are low and do not rise to the requisite extent within 1 hour.

“Rule in”: an NSTEMI is highly likely if the hs-cTn levels are already markedly high on admission or if they rise to the requisite extent within one hour.

Note: the cutoff levels given here are assay-specific. Further algorithms for other hs-cTn assays, with different cutoff levels, are currently being developed.

hs-cTnT: highly sensitive cardiac troponin T; hs-cTnI: highly sensitive cardiac troponin I