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cardio.stemi.posterior.v1PRODUCTION
cardio.stemi.posterior.v1

Isolated posterior wall STEMI (LCx / PDA culprit)

cardiologyacuteadult
Hard-required inputs
0 / 8
Care setting:

Encounter flow

10/12 authored

Canonical 12-phase frame with authored status for this dossier.

Current phase

Frame

Detailed

Isolated posterior STEMI = LCx or posterior descending artery culprit; characteristically MISSED because standard 12-lead shows ST↓ rather than ST↑ — historical under-treatment per Khan 2013 PMID 23877546; route to cardio.stemi.core.v1 for the reperfusion arc

Inputs
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Advance rule
Set
Advance when

posterior STEMI suspected/confirmed

Patient inputs (8)

Older patients more likely to present atypically; under-recognition rate higher (Khan PMID 23877546)

Contrast nephropathy + DOAC dosing if AF post-MI

Anterior ST↓ V1-V3 ≥0.5 mm + tall R waves V1-V2 with R/S ratio >1 in V2 (mirror image); inferior leads may have subtle changes if RCA-PDA territory

Posterior leads V7-V9 ST↑ ≥0.5 mm CONFIRMS isolated true posterior STEMI; AHA 2025 Class I if any V1-V3 ST↓ raises suspicion

Confirms infarct; required given ECG-only diagnosis often subtle and easily missed

Posterior wall motion abnormality (often missed on standard parasternal views; need apical 2-chamber + apical long-axis); LV function

Hypotension uncommon in isolated posterior STEMI but indicates large LCx infarct or concurrent inferior involvement

LCx vs RCA-PDA culprit confirmation; LCx lesions historically under-treated due to ECG silence — vigilant suspicion required

* = hard-required. Engine cannot meaningfully run until these are filled.

Severity triggers (4)

4 need judgement
  • informationallife_threateningposterior_stemi_with_severe_mitral_regurgitation
    New harsh apical/axillary holosystolic murmur post-posterior-MI + acute pulmonary edema → posteromedial papillary muscle ischemia/rupture
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationallife_threateningposterior_stemi_with_cardiogenic_shock
    Posterior STEMI + SBP <90 + lactate ≥2 — large LCx territory or concurrent inferior involvement
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalsevereposterior_stemi_under_recognition_risk
    Patient presents with ischemic chest pain + only V1-V3 ST↓ on standard 12-lead — high under-recognition risk; posterior leads NOT obtained → potential mis-classification as NSTEMI / unstable angina
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalsevereposterior_stemi_with_concurrent_inferior_extension
    Posterior STEMI extends to inferior territory → inferolateral / inferoposterior MI; complication profile expands to include AV block + RV extension
    Trigger could not be auto-evaluated — needs clinician judgement.

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RISK_STRATIFICATIONoptionalDrives risk stratification
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Recommended regimen

Posterior STEMI complication phenotype — same regimen as parent cardio.stemi.core.v1; specialization centered on RECOGNITION + MR vigilance
axis: posterior_stemi_complication_phenotype
Selected axis "Posterior STEMI complication phenotype — same regimen as parent cardio.stemi.core.v1; specialization centered on RECOGNITION + MR vigilance" by default fallback (first axis)
  • aspirin
    first line
    antiplatelet_cox1
    162-325 mg chewed • PO • load + 81 mg daily
    triggers: stemi_post_rosc
    ACC/AHA 2025 ACS Class I; same as parent
    rxcui 243670
  • ticagrelor
    first line
    p2y12_inhibitor
    180 mg load → 90 mg BID • PO • BID × 12 mo default DAPT
    triggers: stemi_pci_planned
    PLATO PMID 19717846; same as parent
    rxcui 1116632
  • unfractionated heparin
    first line
    anticoagulant_indirect_at_iii
    70-100 U/kg IV bolus then per ACT • IV • titrated
    triggers: pci_planned
    AHA 2025 Class I PCI anticoagulant; same as parent
    rxcui 5224
  • atorvastatin
    first line
    statin_high_intensity
    80 mg PO daily • PO • daily
    triggers: stemi_confirmed
    PROVE-IT PMID 15007110; LDL goal <55 per AHA 2018 lipid (now <55 mg/dL secondary prevention)
    rxcui 83367

outpatient playbook — drug actions (1)

  1. 1. continue secondary-prevention bundle
    rxcui 243670
    ASA 81 + ticagrelor 90 BID × 12 mo + atorvastatin 80 + BB if EF<40 • PO • as scheduled
    trigger: post-posterior-MI
    AHA 2025

Auto-drafted A&P note

outpatient

Subjective

- Possible entry pathways: V1-V3 ST↓ ≥0.5 mm + tall R waves V1-V2 (mirror image of posterior); CONFIRM with V7-V9 ST↑ ≥0.5 mm; V7-V9 posterior leads ST↑ ≥0.5 mm = isolated true posterior STEMI; Ischemic chest pain + only V1-V3 ST↓ — high suspicion for posterior STEMI; obtain V7-V9 immediately.

Objective

- No vitals, labs, or imaging entered for this encounter.

Assessment

**Isolated posterior wall STEMI (LCx / PDA culprit)** (cardio.stemi.posterior.v1).
Scope: Isolated posterior STEMI = LCx or posterior descending artery culprit; characteristically MISSED because standard 12-lead shows ST↓ rather than ST↑ — historical under-treatment per Khan 2013 PMID 23877546; route to cardio.stemi.core.v1 for the reperfusion arc

No severity triggers fired against current inputs.

Plan

Regimen axis: **Posterior STEMI complication phenotype — same regimen as parent cardio.stemi.core.v1; specialization centered on RECOGNITION + MR vigilance**.
1. aspirin 162-325 mg chewed PO load + 81 mg daily (antiplatelet_cox1, first line) — ACC/AHA 2025 ACS Class I; same as parent
2. ticagrelor 180 mg load → 90 mg BID PO BID × 12 mo default DAPT (p2y12_inhibitor, first line) — PLATO PMID 19717846; same as parent
3. unfractionated heparin 70-100 U/kg IV bolus then per ACT IV titrated (anticoagulant_indirect_at_iii, first line) — AHA 2025 Class I PCI anticoagulant; same as parent
4. atorvastatin 80 mg PO daily PO daily (statin_high_intensity, first line) — PROVE-IT PMID 15007110; LDL goal <55 per AHA 2018 lipid (now <55 mg/dL secondary prevention)

Setting playbook (outpatient) — Long-term cardiology surveillance: secondary prevention bundle maintenance; MR follow-up if posteromedial papillary involvement; cardiac rehab completion
5. continue secondary-prevention bundle ASA 81 + ticagrelor 90 BID × 12 mo + atorvastatin 80 + BB if EF<40 PO as scheduled — post-posterior-MI (AHA 2025)

Non-pharmacologic actions:
- Cardiac rehab maintenance phase
- MR surveillance if present

AVOID / contraindication checks:
- Dapt_avoid_active_bleeding (AHA 2025)
- High_intensity_statin_avoid_active_liver_disease (label)
- Beta_blocker_avoid_acute_hf_or_cs (AHA 2025)

Monitoring

Regimen monitoring:
- serial echo for posterior wall motion recovery
- serial echo for mr severity (posteromedial papillary involvement)
- standard secondary prevention timeline

Setting (outpatient) monitoring:
- Quarterly + annual EF + lipid + MR severity

Follow-up plan: Cardiology follow-up; echo at 40 d for LVEF reassessment + ICD eligibility (lower than anterior); cardiac rehab
- Close-out criterion: cardiac rehab booked + EF re-assessed

Monitoring phase: Telemetry; daily exam for new MR murmur; echo at 24-72h for posterior wall motion + MR assessment; standard secondary-prevention timeline

Disposition

Current setting: outpatient — Long-term cardiology surveillance: secondary prevention bundle maintenance; MR follow-up if posteromedial papillary involvement; cardiac rehab completion

Disposition criteria:
- Long-term continuation; cross-link to cardio.hf.core.v1 if HFrEF persists; cross-link to cardio.valvular_disease.v1 if MR moderate-severe

Escalation triggers (move to higher acuity):
- Worsening MR → mitral repair eval
- EF declining despite GDMT → advanced HF eval
- Recurrent angina → cath re-eval

Earlier-Return Triggers

Return-precaution thresholds (watch for):
- [LIFE_THREATENING] New harsh apical/axillary holosystolic murmur post-posterior-MI + acute pulmonary edema → posteromedial papillary muscle ischemia/rupture
- [LIFE_THREATENING] Posterior STEMI + SBP <90 + lactate ≥2 — large LCx territory or concurrent inferior involvement
- [SEVERE] Patient presents with ischemic chest pain + only V1-V3 ST↓ on standard 12-lead — high under-recognition risk; posterior leads NOT obtained → potential mis-classification as NSTEMI / unstable angina

Citations

- 2025 ACC/AHA ACS Guideline + ESC 2023 ACS + Boden 1991 + Khan 2013 [PMID:37622670](https://pubmed.ncbi.nlm.nih.gov/37622670/)
- Cited evidence (PMID 35718438) [PMID:35718438](https://pubmed.ncbi.nlm.nih.gov/35718438/)
- Cited evidence (PMID 38587234) [PMID:38587234](https://pubmed.ncbi.nlm.nih.gov/38587234/)
- Cited evidence (PMID 31475795) [PMID:31475795](https://pubmed.ncbi.nlm.nih.gov/31475795/)
- Cited evidence (PMID 1750584) [PMID:1750584](https://pubmed.ncbi.nlm.nih.gov/1750584/)

Last reconciled with current guidelines: 2026-05-14.
References