Morphology & chamber abnormalities

Pulmonary embolism (S1Q3T3 pattern)

ECG criteria

Sinus tachycardia, S in I, Q in III, inverted T in III; right heart strain.

Related: morphology & chamber abnormalities

Acute pericarditis
Diffuse concave ST elevation with PR depression; no reciprocal changes.
Left ventricular hypertrophy
Voltage criteria (Sokolow-Lyon ≥35 mm), often with strain pattern in lateral leads.
Right ventricular hypertrophy
Right axis deviation, dominant R in V1, deep S in V6, often RV strain.