FCPS Paediatrics TOACS · ECG of Myocarditis

✅ Candidate's answer:
• ECG findings in myocarditis:
  - Low voltage QRS: Reduced amplitude of QRS complexes in multiple leads (due to myocardial edema or infiltrative process).
  - Diffuse non-specific ST-T changes: ST segment elevation (usually concave, may mimic pericarditis) or depression, T wave flattening or inversion.
  - Sinus tachycardia: Most common rhythm (due to fever, heart failure, or sympathetic activation).
  - Conduction abnormalities: PR prolongation, AV block (first-degree to third-degree).
  - Arrhythmias: Premature ventricular contractions (PVCs), ventricular tachycardia (VT), atrial arrhythmias.
  - Low voltage: May be absent in some cases.
  - Pathological Q waves: May appear if there is myocardial necrosis (pseudo-infarct pattern).
• Differentiation from pericarditis: Pericarditis has diffuse ST elevation (concave) + PR depression, no low voltage, no arrhythmias (usually). Myocarditis has low voltage, diffuse ST changes, and arrhythmias.

✅ Candidate's answer:
• Causes of myocarditis:
  1️⃣ Viral (most common): Coxsackievirus B (most common), adenovirus, parvovirus B19, influenza, EBV, CMV, HIV, COVID-19 (SARS-CoV-2), enterovirus.
  2️⃣ Post-infectious/immune-mediated: MIS-C (multisystem inflammatory syndrome in children), post-viral (post-streptococcal, post-COVID).
  3️⃣ Bacterial: Diphtheria, Lyme disease (Borrelia), Mycoplasma, Chlamydia, Rickettsia, syphilis.
  4️⃣ Autoimmune: Systemic lupus erythematosus (SLE), juvenile idiopathic arthritis (JIA), sarcoidosis, vasculitis.
  5️⃣ Drug-induced: Anthracyclines (doxorubicin), cyclophosphamide, clozapine, lithium, cocaine, amphetamines.
  6️⃣ Toxic: Alcohol, heavy metals.
  7️⃣ Giant cell myocarditis: Rare, severe, aggressive, requires immunosuppression.
  8️⃣ Eosinophilic myocarditis: Associated with eosinophilia (drugs, parasites, hypereosinophilic syndrome).
  9️⃣ Idiopathic: No identifiable cause (40-50%).

✅ Candidate's answer:
• Diagnostic workup:
  1️⃣ ECG: Low voltage, ST-T changes, arrhythmias.
  2️⃣ Cardiac biomarkers:
    - Troponin I/T: Elevated in myocardial injury (most sensitive).
    - CK-MB: May be elevated.
    - BNP/NT-proBNP: Elevated in heart failure.
  3️⃣ Echocardiogram: Shows LV dysfunction (global or regional wall motion abnormalities), LV dilation, pericardial effusion. May be normal in mild cases.
  4️⃣ Chest X-ray: Cardiomegaly, pulmonary congestion.
  5️⃣ Cardiac MRI (gold standard non-invasive): Uses Lake Louise criteria (2 of 3 required):
    - T2-weighted imaging (myocardial edema).
    - Early gadolinium enhancement (hyperemia/inflammation).
    - Late gadolinium enhancement (LGE) – subepicardial or midwall pattern (viral myocarditis) vs subendocardial (MI).
  6️⃣ Endomyocardial biopsy: Gold standard but invasive. Indicated in:
    - Giant cell myocarditis (immunosuppression needed).
    - Eosinophilic myocarditis.
    - Suspected vasculitis or infiltrative disease.
    - Fulminant myocarditis not responding to therapy.
  7️⃣ Viral serology/PCR: May identify causative virus (blood, throat swab, stool).

✅ Candidate's answer:
• Role of troponin:
  - Troponin I/T is a sensitive marker of myocardial injury and is elevated in most cases of myocarditis.
  - It is used to differentiate myocarditis from pericarditis (troponin is usually normal in isolated pericarditis) and to assess the severity of myocardial injury.
  - Is it always elevated? No. In mild cases or early in the disease, troponin may be normal. A normal troponin does not exclude myocarditis.
  - Monitoring: Serial troponin levels can be used to track the course of the disease (trending down suggests recovery).
  - Prognostic value: Higher troponin levels are associated with more severe myocardial injury but do not predict long-term outcomes.

✅ Candidate's answer:
• Lake Louise criteria (2009, updated 2018):
  - Two of the following three are required for the diagnosis of myocarditis:
    1️⃣ T2-weighted imaging: Focal or diffuse myocardial edema (T2 signal intensity ratio >2.0 or myocardial edema >1 standard deviation).
    2️⃣ Early gadolinium enhancement (EGE): Hyperemia and inflammation (signal intensity ratio >4.0 in the first 1-2 minutes after contrast).
    3️⃣ Late gadolinium enhancement (LGE): Myocardial necrosis or fibrosis (≥1 SD above normal).
• Pattern of LGE in myocarditis:
  - Subepicardial or midwall (most common in viral myocarditis) – unlike myocardial infarction (subendocardial/transmural).
  - Patchy, non-ischemic distribution – not following a coronary artery territory.
  - LGE may persist after recovery, indicating fibrosis.
• Role of MRI: Non-invasive diagnosis, assessment of LV function, fibrosis detection, and monitoring.

✅ Candidate's answer:
• Echocardiographic findings in myocarditis:
  - LV dysfunction: Reduced LVEF (can be mild to severe).
  - Regional wall motion abnormalities: Hypokinesis, akinesis, or dyskinesis (often patchy).
  - LV dilation: If severe or chronic.
  - Pericardial effusion: Common (myopericarditis).
  - RV dysfunction: May also be present.
  - Valvular abnormalities: Mitral regurgitation (secondary to LV dilation).
• Differentiation from dilated cardiomyopathy (DCM):
  - Myocarditis: Acute onset, often with fever/viral illness, troponin elevation, patchy wall motion abnormalities, LGE on MRI.
  - DCM: Chronic, progressive, symmetric LV dilation, globally reduced EF, no LGE (or different pattern), no troponin elevation in chronic phase.

✅ Candidate's answer:
• Management of acute myocarditis is primarily supportive:
  1️⃣ Admit to ICU if hemodynamically compromised.
  2️⃣ Heart failure therapy:
    - Diuretics: Furosemide for pulmonary congestion.
    - Inotropes: Milrinone (phosphodiesterase inhibitor) – preferred in myocarditis (no increase in myocardial oxygen demand). Dobutamine or dopamine may be used if milrinone is unavailable.
    - Avoid digoxin – arrhythmogenic.
  3️⃣ Mechanical circulatory support:
    - ECMO (veno-arterial) for fulminant myocarditis (refractory cardiogenic shock, cardiac arrest).
    - VAD (ventricular assist device) as bridge to recovery or transplant.
  4️⃣ IVIG: 2 g/kg over 2 days – may have benefit in some cases (controversial).
  5️⃣ Corticosteroids: For giant cell myocarditis, eosinophilic myocarditis, or autoimmune myocarditis (not for routine viral myocarditis).
  6️⃣ Avoid NSAIDs (may worsen myocardial injury).
  7️⃣ Anticoagulation: If LV thrombus is present.

✅ Candidate's answer:
• ECMO indications in myocarditis:
  - Fulminant myocarditis with refractory cardiogenic shock (despite inotropes).
  - Cardiac arrest (post-resuscitation).
  - Life-threatening arrhythmias refractory to medical therapy.
  - Bridge to recovery – most patients with fulminant myocarditis recover within 1-2 weeks with ECMO support.
• Prognosis:
  - Good: 60-80% survival to discharge with ECMO in children.
  - Recovery: Many patients recover LV function within weeks to months.
  - Transplant: If no recovery and LV dysfunction persists.

✅ Candidate's answer:
• IVIG (intravenous immunoglobulin): Used in some cases of acute myocarditis.
  - Mechanism: Modulates immune response, anti-inflammatory, neutralizes viral particles.
  - Dose: 2 g/kg IV over 2 days (divided doses).
  - Is it always indicated? No. The evidence for IVIG in myocarditis is controversial.
  - When to consider:
    - Fulminant myocarditis – may reduce inflammation.
    - MIS-C – part of the treatment protocol (with corticosteroids).
    - Idiopathic or post-viral myocarditis – some experts use it, but not universal.
  - Side effects: Headache, aseptic meningitis, thrombosis, renal failure.

✅ Candidate's answer:
• Endomyocardial biopsy (EMB) is the gold standard for diagnosing myocarditis (Dallas criteria).
  - Indications:
    1️⃣ Fulminant myocarditis with refractory heart failure – to rule out giant cell myocarditis or eosinophilic myocarditis.
    2️⃣ Giant cell myocarditis – requires immunosuppression (corticosteroids ± azathioprine).
    3️⃣ Eosinophilic myocarditis – treat with corticosteroids.
    4️⃣ Suspected vasculitis or infiltrative disease (sarcoidosis, hemochromatosis).
    5️⃣ Uncertain diagnosis – when non-invasive tests are inconclusive.
  - Limitations: Low sensitivity (patchy inflammation) – false-negative results are common.
  - Risks: Perforation, arrhythmias, bleeding.

✅ Candidate's answer:
• Giant cell myocarditis (GCM): A rare, aggressive form of myocarditis characterized by multinucleated giant cells, eosinophils, and lymphocytes on biopsy.
• Features:
  - Young adults (most common), but can occur in children.
  - Rapid progression to heart failure, arrhythmias, and death.
  - Poor prognosis without treatment.
• Treatment:
  - Immunosuppression: Corticosteroids (prednisone) + azathioprine or cyclosporine.
  - Mechanical support: Often requires VAD or transplant.
• Differentiation from lymphocytic myocarditis:
  - Lymphocytic: Most common, usually viral, milder, often recovers with supportive care.
  - Giant cell: Severe, requires immunosuppression, poor prognosis without treatment.

✅ Candidate's answer:
• MIS-C (Multisystem Inflammatory Syndrome in Children): A post-infectious complication of COVID-19, often presenting with myocarditis, shock, and multi-organ involvement.
• Management of MIS-C myocarditis:
  1️⃣ IVIG: 2 g/kg (first-line).
  2️⃣ Corticosteroids: Methylprednisolone 1-2 mg/kg/day (or pulse dose for severe cases).
  3️⃣ Inotropes: Milrinone (preferred), dobutamine, or epinephrine for shock.
  4️⃣ Anti-inflammatory agents: Anakinra (IL-1 inhibitor) for refractory cases.
  5️⃣ Anticoagulation: Aspirin (antiplatelet) and sometimes therapeutic anticoagulation (warfarin/LMWH) if coronary aneurysms are present.
  6️⃣ ECMO: For refractory cardiogenic shock.
  7️⃣ Monitoring: Echocardiogram for LV function and coronary artery aneurysms.

✅ Candidate's answer:
• Prognosis is variable:
  - Mild myocarditis: Most children recover fully with supportive care (LV function returns to normal).
  - Fulminant myocarditis: Can be fatal without ECMO; with ECMO, 60-80% survive, and many recover LV function.
  - Giant cell myocarditis: Poor prognosis; often requires transplant.
  - Long-term complications:
    - Dilated cardiomyopathy (if LV dysfunction persists).
    - Arrhythmias (ventricular tachycardia, heart block).
    - Heart failure – may require transplant.
  - Follow-up: Regular echocardiograms, ECGs, and cardiology visits. Avoid competitive sports for 3-6 months after recovery.

✅ Candidate's structured answer:
• “Your child has a condition called myocarditis – inflammation of the heart muscle. This is usually caused by a viral infection, and it can make the heart pump less effectively.”
• “The ECG shows some changes – low voltage and non-specific ST changes – which are typical of myocarditis. We will also do blood tests (troponin) and an echocardiogram (heart ultrasound) to assess the function of the heart.”
• “The good news is that most children with myocarditis recover with supportive care. We will monitor your child closely in the hospital, give medications to support the heart, and if needed, we have treatments like ECMO to support the heart while it recovers.”
• “It will take some time for the heart to heal – usually weeks to months. Your child will need to avoid strenuous activities for a while and will have regular cardiology follow-up.”
• “We are here to support you and your child every step of the way.”