Early 12-lead and immediate cath lab activation saves heart muscle. Time = myocardium.
Steps by Cert Level
AEMT: 12-lead ECG as early as possible (goal: contact-to-ECG < 10 min). Identify STEMI: ST elevation > 1mm in 2 contiguous limb leads or > 2mm in precordial leads. Transmit 12-lead to receiving hospital. Aspirin 324mg PO chewed. NTG 0.4mg SL (if SBP > 100, no PDE5 inhibitors in 24–48h).
PARAMEDIC: STEMI alert to receiving cath lab immediately — bypass non-PCI hospital if transport time allows. Heparin per medical control. Morphine 2–4mg IV for pain (controversial — use judiciously). Repeat 12-lead every 5–10 min. Posterior STEMI: ST depression V1–V3 + tall R waves = do right-sided leads.