What is the management approach for a pediatric patient presenting with ST elevation?

Management of ST Elevation in Pediatric Patients

In pediatric patients presenting with ST elevation, immediately perform urgent echocardiography to assess for structural heart disease and mechanical complications, while simultaneously considering non-ischemic etiologies (particularly myocarditis and Kawasaki disease) before activating adult STEMI protocols, as true atherosclerotic myocardial infarction is exceedingly rare in children. 1

Initial Diagnostic Approach

The critical first step is distinguishing between the rare true STEMI and the more common pediatric causes of ST elevation:

• Obtain a 12-lead ECG within 10 minutes and compare with any prior ECGs to determine if ST elevation is new or chronic 1
• Perform immediate transthoracic echocardiography to assess ventricular function, wall motion abnormalities, and rule out mechanical complications 1
• Assess clinical context carefully: Look for fever, myalgia, rash (suggesting myocarditis or Kawasaki disease) versus typical anginal chest pain (suggesting true STEMI) 2, 3
• Obtain cardiac troponins immediately, recognizing that elevation in pediatric patients more commonly reflects myocarditis rather than coronary occlusion 3

Common Pediatric Etiologies of ST Elevation

Myocarditis

• 72% of pediatric myocarditis patients have abnormal ECGs at presentation, with 41% showing ST elevation 3
• ST elevation in myocarditis typically presents with fever, viral prodrome, and diffuse rather than territorial ECG changes 3
• Patients with ST elevation at presentation have higher peak troponin levels (18.4 vs 7.7 ng/ml) and require more intensive monitoring 3

Kawasaki Disease with Coronary Thrombosis

• Coronary thrombosis in Kawasaki disease requires different management than adult STEMI due to larger thrombus burden and different pathophysiology 1
• Monitor with echocardiography at least twice weekly while coronaries are rapidly expanding, and weekly for giant aneurysms in the first 45 days 1
• Myocardial infarction in young children may be silent or present with nonspecific symptoms (fussiness, vomiting, shock) rather than chest pain 1

Management Algorithm

If True STEMI Cannot Be Excluded:

Activate emergency protocols immediately if the patient has: 2

• Ongoing ischemic symptoms with dynamic ST elevation
• Hemodynamic instability
• New regional wall motion abnormalities on echocardiography

Primary PCI is preferred over fibrinolysis in this scenario, as it provides definitive diagnosis and avoids bleeding risk in patients who may have thrombocytopenia from other causes 2

For Confirmed Kawasaki Disease with Coronary Thrombosis:

Administer thrombolytic therapy for occlusive or near-occlusive coronary thrombosis: 1

• tPA intravenously plus oral aspirin and intravenous heparin
• Monitor fibrinogen (keep >100 mg/dL) and clotting studies at least daily
• Consider reduced-dose thrombolytic therapy combined with abciximab (0.25 mg/kg bolus over 30 minutes, followed by 0.125 μg·kg⁻¹·min⁻¹ for 12 hours) for large thrombus burden 1

For patients of sufficient size, mechanical restoration of coronary blood flow via cardiac catheterization should be performed by experienced adult interventional cardiologists 1

For Myocarditis:

• Supportive care with continuous cardiac monitoring for at least 24 hours in a telemetry bed 4, 3
• Patients with abnormal ECGs at presentation require longer hospitalization (median 5 vs 2 days) and more ICU time 3
• Serial ECG monitoring at 5-10 minute intervals to assess for dynamic changes 2

Critical Pitfalls to Avoid

• Do not assume all ST elevation in children is benign: 28% of myocarditis patients have completely normal ECGs at presentation, and missing true coronary pathology can be fatal 3
• Do not delay echocardiography: Immediate imaging is essential to differentiate regional wall motion abnormalities (suggesting ischemia) from global dysfunction or pericardial effusion (suggesting myocarditis/pericarditis) 1, 2
• Do not use adult STEMI time targets blindly: The 120-minute door-to-balloon time applies to adult atherosclerotic disease, not pediatric etiologies 1
• Do not miss Kawasaki disease coronary thrombosis: Sudden worsening in ventricular function or ECG changes should heighten suspicion, especially in the first 45 days of illness 1
• Do not administer fibrinolysis without ruling out mechanical complications and considering thrombocytopenia risk 1

Monitoring and Follow-up

• For giant coronary aneurysms in Kawasaki disease: Echocardiography at least twice weekly during rapid expansion phase, then weekly for first 45 days, monthly until third month, then every 3 months until end of first year 1
• For myocarditis: Serial troponins and ECGs, with recognition that ST elevation correlates with higher troponin levels and may guide management intensity 3
• Continuous cardiac monitoring with defibrillator capacity immediately available for all patients with ST elevation 4