A 55-year-old woman presents with a 3-hour history of crushing chest pain radiating to the jaw. ECG shows ST depression in V1–V4 with tall R waves in V1–V2. Which of the following best explains this ECG pattern?
- A Anterior STEMI
- B Posterior STEMI (reciprocal changes) ✓
- C Right bundle branch block
- D Left ventricular hypertrophy
Correct answer: B. Posterior STEMI (reciprocal changes)
Explanation
ST depression in V1–V4 with tall, broad R waves and upright T waves in V1–V2 represent reciprocal (mirror image) changes of a posterior STEMI. True posterior MI is confirmed by placing posterior leads (V7–V9) which show ST elevation. Posterior MI often involves the RCA or left circumflex territory. Recognising this pattern is critical because the treatment is urgent reperfusion, not anti-ischaemic therapy alone. RBBB produces an RSR' pattern in V1, not ST changes with tall R waves.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.