A 58-year-old man with hypertension presents to the emergency department with acute onset chest pain radiating to the left arm. His vital signs are stable. The 12-lead ECG shows ST elevation in leads II, III, and aVF with reciprocal ST depression in leads I and aVL. What is the most appropriate immediate next step in management?

Question

Accepted Answer

C. Administer aspirin 325 mg and clopidogrel 600 mg, then arrange primary percutaneous coronary intervention (PCI). ## Clinical Scenario Analysis

This patient presents with **acute ST-elevation myocardial infarction (STEMI)** of the **inferior wall** (ST elevation in II, III, aVF with reciprocal changes in I, aVL).

## Pathophysiology

Inferior STEMI typically results from **right coronary artery (RCA) occlusion** (85% of cases). The ST elevation indicates **acute transmural myocardial necrosis** with ongoing myocardial injury — time-sensitive intervention is critical to salvage viable myocardium.

## Management Algorithm

```mermaid
flowchart TD
  A[STEMI Diagnosis on ECG]:::outcome --> B{Time since symptom onset?}:::decision
  B -->|< 12 hours| C[PCI-capable facility available?]:::decision
  C -->|Yes| D[Dual antiplatelet therapy + Primary PCI within 90 min]:::action
  C -->|No| E[Fibrinolytic therapy + Transfer for rescue PCI]:::action
  B -->|> 12 hours, stable| F[Dual antiplatelet + Coronary angiography within 24 hrs]:::action
  D --> G[Reperfusion & Risk Stratification]:::outcome
```

## Key Point:
**Primary PCI is the gold standard for STEMI management** when performed within 120 minutes of first medical contact (FMC). In this case, the patient is within the therapeutic window and dual antiplatelet therapy (aspirin + P2Y₁₂ inhibitor) must be initiated immediately before PCI.

## High-Yield Facts

| Intervention | Timing | Evidence |
|---|---|---|
| **Dual antiplatelet therapy** | Immediately (pre-PCI) | Reduces stent thrombosis & mortality |
| **Primary PCI** | Within 90 min of FMC (120 min acceptable) | Superior to fibrinolysis; reduces reinfarction |
| **Fibrinolysis** | If PCI unavailable; within 30 min of FMC | Backup strategy; higher reinfarction risk |

## Clinical Pearl:
**Inferior STEMI with RV involvement** (look for ST elevation in V4R) requires careful fluid management — avoid aggressive diuresis as RV infarction is preload-dependent. However, this does not change the acute reperfusion strategy.

## Warning:
~~Troponin and repeat ECG are diagnostic tools, not therapeutic interventions~~ — in acute STEMI, diagnosis is already established by ECG; time must not be wasted on confirmatory testing. The mantra is "time is myocardium."

[cite:Harrison 21e Ch 297]

![ECG Interpretation Basics diagram](https://mmcphlazjonnzmdysowq.supabase.co/storage/v1/object/public/blog-images/explanation/3396.webp)

Answer

A. Administer sublingual nitroglycerin and observe for symptom resolution

Answer

B. Obtain a troponin level and repeat ECG in 30 minutes

Answer

D. Start intravenous heparin and arrange for coronary angiography within 24 hours

Explanation

Clinical Scenario Analysis

Pathophysiology

Management Algorithm

Key Point:

High-Yield Facts

Clinical Pearl:

Warning:

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Intervention	Timing	Evidence
Dual antiplatelet therapy	Immediately (pre-PCI)	Reduces stent thrombosis & mortality
Primary PCI	Within 90 min of FMC (120 min acceptable)	Superior to fibrinolysis; reduces reinfarction
Fibrinolysis	If PCI unavailable; within 30 min of FMC	Backup strategy; higher reinfarction risk