Describe the indication and findings of 12-lead ECG.
Indicated for every patient with suspected ACS (best initial test)
ECG changes in STEMI
ECG changes in NSTEMI/unstable angina
Compare with previous ECGs (if available).
Consider serial ECGs if the initial ECG is negative or inconclusive, as ECG findings are dynamic and signs of ischemia can appear or disappear within minute
Which routine lab studies should be obtained?
CBC, BMP, coagulation panel
Anemia may exacerbate myocardial ischemia. Thrombocytopenia and/or coagulopathies may affect management options, e.g., the use of anticoagulants.
Describe the use of Troponin.
Troponin: all patients at arrival (see also “Cardiac biomarkers”)
Conventional assay: 3–6 hours
High-sensitivity troponin (hscTn): 1–3 hours
Interpretation alongside clinical findings
STEMI/NSTEMI: elevation > 99thpercentile PLUS change ≥ 20% on repeat testing
Unstable angina: no detectable elevation
Describe the use, indication and findings of TTE.
TTE is generally not necessary and should not delay reperfusion therapy. However, it may be a helpful study in patients with atypical symptoms or if the diagnosis is unclear.
Infarct-like symptoms but inconclusive ECG findings
Evaluation for complications of myocardial infarction
Wall motion abnormalities
Decreased LV function
Signs of different conditions that cause chest pain