How many free questions can I ask
There's no limit on how many questions you can ask me! Feel free to ask as many as you'd like - I'm here to help with anything across any topic. What would you like to know?
C6BAC6E7-7D3E-4F81-B196-BD44A7DD54E3.png
Is this ok?
This is a well-made cardiology reference chart on the Right Coronary Artery (RCA). The content is accurate and well-organized. Here's a quick review:
What's correct and well-done:
- RCA anatomy and course description is accurate (right AV groove, PDA, PLB)
- SA nodal artery (~60% from RCA, ~40% from LCx) and AV nodal artery (~80-90% from RCA) percentages are standard
- Occlusion site breakdown (proximal/mid/distal) with corresponding ECG changes is solid
- The explanation of why RCA occlusion causes ST elevation in II, III, aVF is correct
- V4R as the most sensitive lead for RV infarction - correct
- The vector concept diagrams (sections 6) are a nice touch for understanding net QRS axis
- Lead placement table (section 8) is accurate
Minor points to note:
- The note that "III > II in RCA inferior MI" is a useful high-yield clue and is correctly stated
- V1 elevation being variable in RV infarction (section 5 explanation) is nuanced and accurate
- The qualifier "correlate clinically" in the footer is appropriate given the approximations used
Overall: This is a high-quality, high-yield study chart - accurate, well-structured, and appropriate for medical students, residents, or anyone reviewing cardiology/ECG interpretation. Nothing stands out as incorrect.
Is everything correct in that
Reading File
analyse_media
Finding Sources
Finding Sources
Finding Sources
Reading File
Reading File
Finding Sources
Good findings. Now I have enough textbook data to do a thorough fact-check. Let me compile the analysis:
Detailed Fact-Check of the RCA Chart
Overall the chart is excellent and mostly accurate. Here are the specific points that need attention:
SA Nodal Artery Supply - MINOR DISCREPANCY
The chart states: RCA ~60%, LCx ~40%
Textbooks vary on this:
- Frameworks for Internal Medicine states: RCA 65%, LCx 25%, both 10%
- Rosen's Emergency Medicine states: RCA 55%, LCx 45%
The chart's "~60%/~40%" is a reasonable middle-ground approximation, but it is worth knowing different sources cite different figures. The chart is not wrong - it just represents one set of commonly cited numbers.
AV Nodal Artery Supply - MINOR DISCREPANCY
The chart states: RCA ~80-90%, LCx ~10-20%
Textbooks:
- Frameworks for Internal Medicine: RCA 80%, LCx 10%, both 10%
- Rosen's Emergency Medicine: RCA 90% (right dominant), LCx 10% (left dominant)
The "~80-90%" range is acceptable and covers the spread across sources. No real issue here.
Section 4, Proximal RCA ECG Row: "III > II" - NEEDS CLARIFICATION
The chart consistently states III > II for ALL three occlusion types (proximal, mid, and distal). This is the classic teaching for RCA occlusion specifically.
However, this rule actually helps differentiate RCA vs. LCx occlusion:
- RCA inferior MI: III > II (because the injury vector points right and inferior)
- LCx inferior MI: II > III (injury vector points more leftward)
The chart lists III > II for all RCA occlusion levels, which is correct for RCA. But it applies it identically to all three subtypes without noting that the degree of III > II may differ depending on how much rightward vector exists (strongest in proximal RCA due to RV involvement). This is a minor oversimplification but not wrong per se.
Section 4, Mid RCA - ST Depression Row
The chart says for Mid RCA: reciprocal ST depression in V1-V3 is "common if posterior wall involved."
This is correct - posterior MI causes ST depression in V1-V3 (the reciprocal of posterior elevation seen in V7-V9). No issue here.
Section 5 - "RV forms most of the anterior (sternocostal) surface"
This is anatomically correct. The RV indeed forms the sternocostal (anterior) surface of the heart. The LV forms the left lateral and inferoposterior surface.
Section 8 - Lead Placement Table
| Lead | Chart States | Standard |
|---|---|---|
| V1 | 4th ICS, Right sternal border | Correct |
| V2 | 4th ICS, Left sternal border | Correct |
| V3 | Midway between V2 & V4 | Correct |
| V4 | 5th ICS, Left midclavicular line | Correct |
| V3R | Midway between V1 & V4R (Right side) | Correct |
| V4R | 5th ICS, Right midclavicular line | Correct |
| V7 | 5th ICS, Left posterior axillary line | Correct |
| V8 | 5th ICS, Left midscapular line | Correct |
| V9 | 5th ICS, Left paraspinal line | Correct |
All lead placements are correct.
One Actual Error to Flag
The chart's Section 4, Mid RCA row under "ECG - ST Depression (Reciprocal)" lists:
"No reciprocal changes in V2-V6 usually"
But in the same cell, it says "V1-V3 (common if posterior wall involved)." These two statements slightly contradict each other within the same box - V1-V3 depression IS a reciprocal change in that range. The phrasing is confusing but not factually wrong if you read carefully (V1-V3 depression is from the posterior wall, not from the inferior wall per se). It would be clearer to separate these two mechanisms.
Summary
| Category | Verdict |
|---|---|
| SA nodal artery % | Acceptable approximation (sources vary 55-65%) |
| AV nodal artery % | Correct |
| Lead placements | All correct |
| V4R for RV infarction | Correct |
| III > II in RCA MI | Correct |
| RV anterior surface anatomy | Correct |
| Dominance % (85/8-10/5-7) | Correct |
| One confusing cell in Section 4 mid-RCA | Minor phrasing issue |
Bottom line: The chart is accurate. The SA nodal artery percentage is the one point where different authoritative sources give slightly different numbers (55% to 65%), so the chart's ~60% is not wrong but sits in a contested range depending on which study you reference. Everything else checks out against major emergency medicine and cardiology textbooks.
Mi treatment Australia guidelines
Reading File
Searching the Web
Australia MI myocardial infarction treatment guidelines 2024 National Heart Foundation
Reading Web Page
https://www.heartfoundation.org.au/for-professionals/acs-gui…
Finding Sources
Reading Web Page
https://www.csanz.edu.au/Common/Uploaded%20files/Smart%20Sui…
Finding Sources
I now have the 2025 Australian guidelines from the source PDF. Here is a comprehensive summary:
MI Treatment - Australian Guidelines (NHFA/CSANZ 2025)
The current authority is the National Heart Foundation of Australia & Cardiac Society of Australia and New Zealand (NHFA/CSANZ) Comprehensive Australian Clinical Guideline for Diagnosing and Managing Acute Coronary Syndromes 2025 - this replaced the 2016 guidelines.
Terminology Change (2025 Update)
The 2025 guideline introduces new terminology:
- ACOMI = Acute Coronary Occlusion Myocardial Infarction (replaces "STEMI" as the primary term - includes STEMI + STEMI-equivalents like posterior MI, RV MI, De Winter T-waves, LBBB with modified Sgarbossa criteria)
- NSTEMI terminology retained for non-occlusive MI
STEMI / ACOMI - Reperfusion
Primary PCI (preferred)
| Target | Time |
|---|---|
| PCI-capable centre (patient arrives directly) | Within 60 min of arrival |
| Transfer from non-PCI centre | Within 90 min of first hospital arrival |
| Overall preferred window | PCI within 120 min of first medical contact |
| Symptom onset to presentation | Up to 12 hours (beyond 12h if ongoing ischaemia/haemodynamic compromise) |
- Radial access preferred over femoral (unless contraindicated)
- Pre-hospital cath lab activation recommended to bypass ED
Fibrinolysis (if PCI not available within 120 min)
- Give within 30 minutes of first medical contact
- Pre-hospital administration should be considered
- Tenecteplase is the agent used in Australia
- Age >70 years: use half-dose tenecteplase (pharmaco-invasive strategy)
- After fibrinolysis: transfer to PCI centre for rescue PCI if no reperfusion, or routine angiography within 3-24 hours
NSTEMI / NSTEACS - Risk Stratification
| Risk Level | Criteria | Timing for Angiography |
|---|---|---|
| Very High | Cardiogenic shock, life-threatening arrhythmia, mechanical complication, recurrent intermittent STE, ST depression >1mm in >6 leads | Immediate (within 2h) |
| High | Confirmed NSTEMI, dynamic ECG changes, GRACE score >140 | Early invasive (<24h) |
| Intermediate | GRACE 109-140, elevated troponin | Within 72h |
| Low | GRACE <109, no recurrence | Conservative / non-invasive |
Antiplatelet Therapy (Acute Phase)
- Aspirin 300 mg loading dose immediately, then 100 mg daily long-term
- P2Y12 inhibitor (dual antiplatelet therapy - DAPT):
- Ticagrelor 180 mg load, then 90 mg BD - preferred for STEMI and high-risk NSTEMI
- Prasugrel 60 mg load, then 10 mg daily - alternative (avoid if prior stroke/TIA, age >75, weight <60 kg)
- Clopidogrel 600 mg load - if ticagrelor/prasugrel contraindicated or unavailable
- DAPT duration: 12 months post-PCI standard; may shorten (3-6 months) if high bleeding risk
Anticoagulant Therapy (Acute Phase)
| Setting | Preferred Agent |
|---|---|
| Primary PCI | Unfractionated heparin (UFH) IV bolus (with or without GPIIb/IIIa inhibitor); or bivalirudin |
| Fibrinolysis | Enoxaparin (preferred over UFH) for duration of hospital stay |
| NSTEACS (medical management) | Fondaparinux (preferred) or enoxaparin |
- Stop anticoagulation after PCI in uncomplicated cases
- If patient is already on warfarin/DOAC: specialist individualisation required
Other Acute Treatments
- Oxygen: Only if SpO2 <93% (not routine)
- Nitrates: For ongoing pain/hypertension (avoid if RV infarction, hypotension, or recent PDE5 inhibitor use)
- Morphine: Use cautiously - may delay absorption of oral antiplatelets
- Beta-blockers: Start early if no contraindication (heart failure, bradycardia, cardiogenic shock)
- ACE inhibitor/ARB: Start within 24h, especially if EF reduced or anterior MI
- High-intensity statin: Start immediately (atorvastatin 40-80 mg or rosuvastatin 20-40 mg)
Secondary Prevention (Post-discharge)
- DAPT for 12 months (can extend with ticagrelor 60 mg BD for up to 3 years in high-risk patients - PEGASUS trial basis)
- Statin indefinitely
- ACE inhibitor/ARB indefinitely if EF <40%
- Beta-blocker - at least 1 year if EF reduced
- Eplerenone/spironolactone if EF <35% on ACE-i + beta-blocker
- Cardiac rehabilitation strongly recommended
- Lifestyle: smoking cessation, diet, exercise, BP and diabetes control
Special Populations Noted in 2025 Guidelines
- First Nations peoples: Specific considerations for access and culturally appropriate care
- Women: Tend to present later and are under-treated - guideline explicitly addresses sex disparities
- SCAD (spontaneous coronary artery dissection): Conservative management preferred; avoid fibrinolysis; PCI only if ongoing ischaemia
- MINOCA (MI with non-obstructive coronary arteries): Separate workup pathway (cardiac MRI, provocative testing)
The full guideline PDF is available directly from the Heart Foundation ACS Guideline page. The 2025 version is a major update from 2016 - the key changes are the new ACOMI terminology, updated reperfusion time targets, and specific guidance for SCAD and MINOCA.
This is a shared conversation. Sign in to Orris to start your own chat.