What is the difference in treatment between concave and convex ST elevation?

ST Elevation Morphology: Treatment Implications

The morphology of ST elevation (concave vs. convex) does NOT determine treatment decisions in suspected acute coronary syndrome—both patterns require immediate evaluation for reperfusion therapy if STEMI criteria are met. 1

Primary Treatment Principle

The decision to pursue reperfusion therapy is based on ST elevation magnitude and distribution, not morphology. Treatment is indicated when ST elevation meets diagnostic thresholds: ≥2.5 mm in men <40 years, ≥2 mm in men ≥40 years, or ≥1.5 mm in women in leads V2-V3, and/or ≥1 mm in other leads (in ≥2 contiguous leads). 1

Critical Diagnostic Distinction

Convex ST Elevation

• Strongly suggests acute LAD occlusion and typically indicates larger infarct size with worse left ventricular function at discharge (median LVEF 41%). 2
• Associated with higher peak creatine kinase levels (median 5322 mU/mL) compared to concave morphology. 2
• Requires immediate reperfusion therapy (primary PCI or fibrinolysis if PCI unavailable). 1

Concave ST Elevation

• Cannot be used to exclude STEMI—43% of proven LAD occlusions present with concave morphology. 3
• Concave morphology is associated with shorter symptom duration and better preserved left ventricular function (median LVEF 58%) when MI is present. 3, 2
• However, concave ST elevation is also the classic pattern of pericarditis (typically widespread, not confined to vascular territory, with PR depression in II/V5/V6 and PR elevation in aVR). 4
• When STEMI criteria are met with concave morphology, treat as STEMI with immediate reperfusion. 1

Algorithmic Approach

Step 1: Measure ST elevation magnitude

• If diagnostic thresholds are met in appropriate distribution → proceed to reperfusion regardless of morphology. 1

Step 2: If concave morphology with borderline ST elevation

• Check for pericarditis features: widespread distribution, PR changes, pleuritic chest pain. 4
• Assess for terminal QRS distortion (absence of S-wave in V2-V3 or J-wave ≥50% of R-wave amplitude)—presence strongly favors acute MI over benign patterns. 3, 5
• Consider advanced ECG criteria: The 4-variable formula (0.052×QTc-B - 0.151×QRSV2 - 0.268×RV4 + 1.062×STE60V3) with cutoff ≥18.2 has 88.8% sensitivity and 94.7% specificity for LAD occlusion. 5

Step 3: When diagnosis remains uncertain

• Urgent coronary angiography is necessary to differentiate entities with certainty—do not delay based on morphology alone. 1
• Serial ECGs and cardiac biomarkers (high-sensitivity troponin) are essential but should not delay angiography in high-risk presentations. 1

Common Pitfalls

• Major error: Dismissing concave ST elevation as "early repolarization" or pericarditis without meeting diagnostic criteria—19-24% of LAD occlusions have both concave morphology AND borderline ST elevation. 3
• Concave morphology with shorter symptom duration may represent hyperacute phase before evolution to convex pattern. 3
• In patients with ongoing chest pain and dynamic ECG changes, morphology should never delay reperfusion therapy. 1
• Takotsubo syndrome can mimic STEMI with ST elevation (usually concave, centered on V2-V5), but angiography is required for definitive diagnosis. 1

Treatment Execution

Once STEMI is diagnosed (regardless of morphology):

• Primary PCI is the preferred reperfusion strategy when available within 120 minutes of first medical contact. 1
• Immediate dual antiplatelet therapy (aspirin 150-300 mg + P2Y12 inhibitor), anticoagulation, and transfer to catheterization laboratory. 1
• If PCI unavailable within appropriate timeframe, fibrinolytic therapy followed by routine early angiography (ideally 2-24 hours) for high-risk patients. 1

The morphology provides prognostic information but does not alter the fundamental treatment approach: immediate reperfusion for all STEMI patients. 1, 2