Activate or Wait – 010

38-year-old male with left arm pain, shortness of breath, and dizziness. BP 105/60.

We are five minutes from your tertiary centre.

Would you activate your cath lab/STEMI protocol?

ECG interpretation

Inferior STEMI

  • Marked ST elevation and hyperacute T waves (HATW) in leads II, III, aVF and I
  • Reciprocal ST depression in V1-3 and aVR
  • Q waves in leads I, II
  • T waves in V4-6 are broadened also resembling HATW
  • Borderline first degree AV block

Notably, marked ST depression in V2 > V1 is concerning for right ventricular infarction. These patients are preload sensitive and can develop severe hypotension in response to nitrates.


Key finding:

RCA occlusion


  • Left Main Coronary Artery – mild irregularities
  • Left Anterior Descending Coronary Artery – mild irregularities
  • Left Circumflex Coronary Artery – mild irregularities
  • Right Coronary Artery – dominant and occluded mid-vessel
  • Left ventriculogram – mild-moderate systolic dysfunction

Proceeded to PCI to RCA.


  1. Dual antiplatelet therapy – aspirin 100mg + ticagrelor 90mg BD for 12 months. Aspirin 100mg daily for life
  2. Ongoing aggressive cardiovascular risk factor management
  3. Admit CCU
Clinical Pearls
  • ECG features of RV infarction can be subtle and easily missed. Examine closely for ST depression in V2 relative to an isoelectric ST segment in V1. Diagnosis is confirmed by the presence of ST elevation in right-sided leads (V3R-V6R)
  • These patients are preload dependent and can develop severe hypotension in response to nitrates


Further reading

Online resources


EKG Interpretation

MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

MBBS (Hons), BMSci (Hons). Cardiology Registrar at Royal Perth Hospital in Perth, Australia. Graduate of The University of Western Australia in 2016 with Honours and completed Basic Physician Training with the RACP in 2021. Passion lie in cardiac imaging and electrophysiology.

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