St elevation
Reading File
Finding Sources
Finding Sources
Reading File
Reading File
Loading Image
Here is a detailed analysis of this ECG:
ECG Analysis - Patient: Goutam Ghosh | Date: 05/06/26 | Time: 10:20
Settings: 10 mm/mV, 25 mm/s, AC50Hz, EMG25Hz, DFT0, 0.5Hz-LF, 75Hz
Key Findings
Rhythm: Regular sinus rhythm. Rate approximately 70-80 bpm.
ST Elevation (most prominent findings):
Looking at the leads carefully:
- Leads II, III, and aVF - there is ST elevation visible, suggesting inferior wall involvement (RCA territory most commonly)
- Leads V1-V4 - there appears to be ST elevation in the precordial leads, consistent with anterior wall involvement (LAD territory)
- Reciprocal ST depression - leads I and aVL show reciprocal changes (ST depression), which is the hallmark of inferior STEMI and increases specificity significantly
Q waves: Pathological Q waves may be present in leads II, III, aVF - suggesting infarction is established or evolving.
T waves: Tall peaked T waves (hyperacute T waves) may be visible in some leads, indicating an early/acute phase.
Impression
This ECG pattern is consistent with an Acute STEMI, most likely:
Inferoanterior STEMI OR an Extensive anterior STEMI with inferior extension
- If ST elevation is predominantly in II, III, aVF + V1-V4: consider proximal RCA or dominant circumflex with LAD involvement, OR a wraparound LAD
- Reciprocal depression in I/aVL strongly supports inferior STEMI
Note: The ECG is photographed at an angle with the sheet rotated, making precise millimeter measurements difficult. A digitally acquired ECG reading would allow more precise measurements.
STEMI Diagnostic Criteria (per Washington Manual of Medical Therapeutics)
| Lead Group | Threshold (Men >40 yrs) |
|---|---|
| V2-V3 | ≥ 2 mm at J point |
| All other leads | > 1 mm at J point (in 2 contiguous leads) |
| Inferior leads (II, III, aVF) | > 1 mm |
| Right-sided leads (V3R/V4R) | ≥ 0.5 mm |
Culprit Artery Localization
| ST Elevation Pattern | Likely Culprit |
|---|---|
| II, III, aVF | RCA (right coronary artery) |
| I, aVL, V5-V6 | LCX (left circumflex) |
| V1-V4 | LAD (left anterior descending) |
| II, III, aVF + V1-V3 | Proximal RCA or wraparound LAD |
Immediate Management (STEMI Protocol)
- Activate Cath Lab / Door-to-balloon time goal < 90 minutes
- Aspirin 325 mg loading dose (chewed)
- P2Y12 inhibitor - Ticagrelor 180 mg OR Clopidogrel 600 mg
- Anticoagulation - Heparin UFH 60 U/kg IV bolus (max 4000 U)
- IV access, oxygen if SpO2 <90%, cardiac monitoring
- 12-lead ECG right-sided leads (V3R-V4R) to rule out RV infarction - critical in inferior STEMI because RV involvement changes management (avoid nitrates, use fluid boluses)
- Posterior leads (V7-V9) if V1-V3 shows ST depression (rule out posterior MI)
- Nitroglycerin - use with caution; contraindicated if RV infarction or systolic BP <90 mmHg
Important Caveat
This is a photographic interpretation of a physical ECG strip. The image is rotated and not perfectly flat, which limits precision. Clinical correlation with the patient's symptoms (chest pain, diaphoresis, dyspnea), vitals, troponin levels, and a formal digital ECG reading by the treating physician is mandatory before final diagnosis and management decisions.
If this patient is symptomatic - this is a time-critical emergency. Activate STEMI protocol immediately.
- Harrison's Principles of Internal Medicine 22E, p. 1916; Washington Manual of Medical Therapeutics, p. 148
Create a comparison chart: RCA vs LAD vs LCX infarction presentations
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Reading File
Reading File
Reading File
Reading File
Excellent data. Now I have comprehensive textbook-sourced evidence to build the comparison chart.
RCA vs LAD vs LCX Infarction - Comparison Chart
1. Anatomy & Territory
| Feature | RCA (Right Coronary Artery) | LAD (Left Anterior Descending) | LCX (Left Circumflex) |
|---|---|---|---|
| Wall supplied | Inferior wall, RV free wall, posterior wall (if dominant) | Anterior wall, interventricular septum, apex | Lateral wall, posterior wall (if dominant) |
| Branches | Acute marginal, PDA (usually), SA node artery (55%) | Septal perforators, diagonal branches | Obtuse marginal branches |
| Dominance | Right dominant in ~85% (gives PDA) | - | Left dominant in ~15% (gives PDA) |
| SA/AV node supply | SA node (55%), AV node (90%) | - | SA node (45%), AV node (10%) |
2. ECG Localization
| ECG Finding | RCA | LAD | LCX |
|---|---|---|---|
| ST elevation | II, III, aVF (inferior) | V1-V4 (anterior) | I, aVL, V5-V6 (lateral) |
| Reciprocal ST depression | I, aVL (often prominent) | II, III, aVF | V1-V3 (subtle or absent) |
| Key distinguishing sign | ST III > ST II | aVR elevation >1 mm (proximal); Wellens sign (reperfusion) | Isoelectric/elevated ST in lead I with inferior STE |
| Sensitivity/Specificity | STE III > II: Sens 90%, Spec 71% | RBBB + Q + STE >2.5mm V2: Spec 100% | ST elevation I, aVL, V2-V3 without RCA pattern: Sens 83%, Spec 96% |
| Posterior extension | V7-V9 elevation; V1-V3 reciprocal depression + tall R in V1-V2 | Rare | Common (circumflex often supplies posterior wall) |
| "Electrically silent" risk | Low (classic pattern) | Low | HIGH - LCX territory is often ECG-silent; can present as NSTEMI despite total occlusion |
3. Proximal vs Distal Occlusion (LAD - most clinically important to distinguish)
| Level | ECG Clue | Territory at Risk |
|---|---|---|
| Proximal LAD (before S1 + D1) | STE V1-V4 + STE I/aVL + ST depression II/III/aVF >1 mm; or RBBB with Q wave | Anterior + septal + lateral - massive infarct |
| Mid LAD (after S1, before D1) | STE V1-V4, no aVL changes | Anterior + septal |
| Distal LAD | STE V3-V5 only; sometimes ST elevation II/III/aVF | Apical only |
| Diagonal branch | STE I, aVL, V2-V3 with ST depression II/III/aVF | Lateral |
4. RCA - Proximal vs Distal (critical distinction)
| Level | ECG Clue | Risk |
|---|---|---|
| Proximal RCA | STE II/III/aVF + STE V1 or V4R | RV infarction in ~30% - high-risk |
| Mid/Distal RCA | STE III > II; no V1 involvement | Standard inferior MI |
RV Infarction triad: Hypotension + JVD + clear lungs (Kussmaul sign). Avoid nitrates - preload dependent! Give IV fluids instead.
5. Clinical Presentations
| Feature | RCA | LAD | LCX |
|---|---|---|---|
| Chest pain character | Typical substernal pressure | Typical substernal pressure | Typical OR atypical |
| Hemodynamic instability | Moderate-high (RV involvement, bradyarrhythmias) | Highest (large LV territory) | Low-moderate |
| Bradycardia/Heart block | Common - SA/AV node ischemia → sinus brady, 1st/2nd/3rd degree AVB | Rare (His-Purkinje BBB pattern instead) | Rare |
| Cardiogenic shock risk | Moderate (RV shock possible) | Highest (LV anterior wall) | Lower |
| Mechanical complications | Papillary muscle (posterior) → MR; Free wall rupture | VSD (septal) most common; Free wall rupture; Anterior aneurysm | Papillary muscle (posterior) → MR |
| Arrhythmias | Sinus brady, AVB (vagal), AF | VF, VT, LBBB, RBBB | Less common |
| Mortality | Moderate | Highest (especially proximal) | Moderate; often underdiagnosed |
6. "Which artery is it?" - Quick Decision Flowchart
Inferior STE (II, III, aVF)?
│
├─ ST III > ST II?
│ ├─ YES + STE in V1 or V4R → PROXIMAL RCA (RV infarction - check right leads)
│ └─ YES, no V1/V4R changes → RCA (mid/distal)
│
└─ ST I isoelectric/elevated + lateral STE (V5, V6)?
└─ YES → LCX (circumflex inferior MI)
Anterior STE (V1-V4)?
├─ STE in I + aVL + STE V1-V4 + STD II/III/aVF → PROXIMAL LAD
├─ STE V1-V4 only → MID LAD
└─ STE V3-V5 alone → DISTAL LAD
Lateral STE only (I, aVL, V5-V6)?
└─ LCX (diagonal or obtuse marginal)
aVR elevation + diffuse ST depression everywhere?
└─ LEFT MAIN or Proximal LAD - highest risk, IABP/emergent CABG
7. Management Nuances by Artery
| RCA | LAD | LCX | |
|---|---|---|---|
| Reperfusion | Primary PCI | Primary PCI | Primary PCI (don't miss it - ECG often silent) |
| Nitrates | CONTRAINDICATED if RV infarct | Use cautiously | Can use |
| Fluids | Bolus if RV infarction + hypotension | Cautious (LV failure risk) | Standard |
| Pacing | Transcutaneous pacing on standby (high AVB risk) | Rarely needed acutely | Rarely needed |
| Specific concern | RV shock, high-degree AVB | Cardiogenic shock, VT/VF, VSD | ECG-silent occlusion → missed diagnosis |
Sources: Tintinalli's Emergency Medicine (Table 49-5, ECG Culprit Artery with sensitivity/specificity data); Rosen's Emergency Medicine (Table 64.4, Regional ST Changes); Harrison's Principles of Internal Medicine 22E; Washington Manual of Medical Therapeutics (STEMI criteria)
Generate a quick reference PDF guide for coronary artery territory identification
Reading File
Running Command
Your credits are exhausted. Your daily credits reset tomorrow, or you can purchase a top-up for more.
This is a shared conversation. Sign in to Orris to start your own chat.