Interpretation of this ECG and what has happened explain
Reading File
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Finding Sources
Finding Sources
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ECG Interpretation — ID 3592 | 14-04-2026 | 08:13:16
Technical parameters: 25 mm/s paper speed | 10 mm/mV | HR ≈ 83 bpm | AC filter 50 Hz
Key Findings by Lead
Rhythm: Regular sinus rhythm at ~83 bpm. P waves visible before each QRS.
Inferior leads (II, III, aVF):
- Pathological Q waves present in leads II, III, and aVF
- ST segment elevation in leads II, III, aVF — most prominent in III and aVF
- T-wave changes consistent with ischemic pattern
Lateral/high leads (I, aVL):
- Reciprocal ST depression in aVL — this is a critical corroborating finding
- ST depression in lead I also likely present
Precordial leads (V1–V6):
- V1–V3 may show reciprocal ST depression (posterior wall involvement possible)
- No dominant anterior ST elevation to suggest anterior STEMI
Diagnosis: Acute Inferior STEMI (ST-Elevation Myocardial Infarction)
What Has Happened — Pathophysiology
The culprit vessel is almost certainly the Right Coronary Artery (RCA), which supplies:
- The inferior wall of the left ventricle
- The posterior wall (in right-dominant circulation, ~85% of people)
- The SA node (in ~60%) and AV node (in ~90%)
Sequence of events:
- Atherosclerotic plaque rupture in the RCA → platelet aggregation → thrombus formation → complete or near-complete occlusion
- Ischemia of the inferior myocardium begins within minutes → ionic pump failure → ST elevation on ECG
- Pathological Q waves indicate completed or evolving infarction — some myocardial necrosis has already occurred (this is not hyperacute — Q waves suggest the infarct has been evolving for at least 1–2 hours, possibly longer)
- Reciprocal changes in aVL are a hallmark of inferior STEMI and increase diagnostic confidence significantly
Evolution Stage
The presence of Q waves alongside ST elevation suggests this ECG was captured in the established/evolving phase of the MI — not the very earliest hyperacute phase. The infarct has been developing for likely >1–2 hours.
Red Flags to Watch For
| Complication | Why at Risk |
|---|---|
| AV block (1st, 2nd Mobitz I / 3rd degree) | RCA supplies AV node; inferior MI is the most common cause of complete heart block |
| Bradycardia / sinus node dysfunction | RCA supplies SA node |
| Right ventricular infarction | RCA supplies the RV in right-dominant systems — check V4R; hypotension + clear lungs = classic RV MI triad |
| Papillary muscle ischemia | Can cause acute mitral regurgitation |
Immediate Management (STEMI Protocol)
- Activate Cath Lab — door-to-balloon time target < 90 minutes
- Dual antiplatelet therapy: Aspirin 300 mg + Ticagrelor 180 mg (or Clopidogrel)
- Anticoagulation: Heparin (UFH or LMWH per protocol)
- Oxygen if SpO₂ < 90%
- Avoid nitrates if RV infarction suspected (can cause severe hypotension)
- Primary PCI is gold standard; thrombolytics if PCI not available within 120 min
- Right-sided ECG (V4R) to rule out RV involvement — critical before giving nitrates
⚠️ This ECG pattern requires emergency intervention. If this is a real patient, activate the STEMI protocol immediately.
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