Deadly ECG patterns — recognition and immediate action

Five patterns (examples):

1. de Winter T waves — upsloping J-point ST depression with tall symmetrical anterior T waves; action: treat as proximal LAD OMI → activate cath lab.^[1]
2. Wellens (pain-free) — biphasic or deep inverted T in V2–V3, preserved R waves; action: urgent angiography; never stress test.^[2]
3. Sgarbossa-positive LBBB/paced — concordant STE ≥1 mm, concordant STD V1–V3, or excessively discordant STE (Smith ST/S ≥0.25); action: reperfusion pathway as OMI.^{[3] [4]}
4. Brugada type-1 — coved STE ≥2 mm V1–V2/V3 into negative T; action: treat fever/precipitants, avoid Na-channel blockers, urgent cardiology/ICD pathway if symptomatic. ^[5]
5. Na-channel toxicity (e.g. TCA) — wide QRS + terminal R in aVR; action: NaHCO3 1–2 mmol/kg IV bolus, target pH ~7.45–7.55. ^[6] (Accept also: posterior MI, hyperacute T, torsades/long QT, hyperK sine wave, WPW AF.)

Hyperkalaemia ladder:

1. Stabilise membrane — IV calcium gluconate (or chloride via central/reliable access) if ECG changes/wide QRS/sine wave.
2. Shift — insulin–glucose; nebulised salbutamol; consider bicarbonate if acidotic.
3. Remove — urgent dialysis (especially ESRD); resins adjunctive only, not sole therapy in emergency.