📄 Definition
Myocarditis is inflammation of the myocardium (heart muscle), typically due to infection, autoimmunity, or toxins. It can cause cardiac dysfunction, arrhythmias, and occasionally sudden cardiac death, especially in young adults.
🧫 Causes – Mnemonic: VIRUS-MYOCARD
Viral – Coxsackie B (most common), adenovirus, HIV, influenza, COVID-19
Immune-mediated – SLE, sarcoidosis, autoimmune myocarditis
Rheumatic fever
Uraemia (severe renal disease)
Sepsis or systemic infection
Medications – clozapine, checkpoint inhibitors
Young adults (most affected group)
Other infections – bacterial (e.g. Lyme), fungal, protozoa (e.g. Trypanosoma cruzi – Chagas disease)
Chemotherapy/toxins – e.g. alcohol, cocaine, anthracyclines
Allergic or hypersensitivity reactions
Radiation therapy
Drug-induced (e.g. antibiotics, antiepileptics)
📋 Clinical Features – Mnemonic: CHEST PAIN
Chest pain (pleuritic or angina-like)
Heart failure symptoms (e.g. SOB, orthopnoea, oedema)
Elevated troponin without coronary artery disease
Syncope or palpitations (arrhythmia-related)
Tachycardia (disproportionate to fever)
Pericardial rub (if concurrent pericarditis)
Acute coronary syndrome mimic
Infectious prodrome (fever, myalgia, fatigue)
Non-specific ECG changes (ST elevation, T-wave inversion)
🔬 Investigations – Tiered Approach
🥇 First-Line
ECG – non-specific ST-T changes, arrhythmias
Troponin – often elevated (due to myocardial injury)
CRP/ESR – raised
FBC, U&Es, LFTs – systemic involvement
CXR – pulmonary oedema if HF present
Echo – global hypokinesia, reduced EF
🥈 Second-Line
Cardiac MRI – gold standard for diagnosis (oedema, fibrosis)
Viral serology – may guide cause
Autoimmune screen – ANA, ENA, etc.
COVID-19 PCR or serology
🥉 Tertiary
Endomyocardial biopsy – rarely done unless unclear diagnosis or severe cases
Management – Mnemonic: HEART REST
Heart failure treatment – ACEi, beta-blocker, diuretics (if LV dysfunction)
Exercise restriction – at least 6 months
Arrhythmia monitoring – Holter or telemetry
Remove offending agents – e.g. drugs/toxins
Treat infection or inflammation (antivirals rarely used)
Refer to cardiology – all suspected myocarditis
Echo follow-up
Steroids – only in autoimmune cases
Transplant – for fulminant myocarditis if unresponsive
⚠️ Complications – Mnemonic: SUDDEN
Sudden cardiac death (especially in young athletes)
Unresponsive heart failure
Dilated cardiomyopathy (chronic cases)
Dysrhythmias – VT/VF
Embolism – mural thrombus
Need for transplantation in severe cases
Last updated in line with NICE Clinical Knowledge Summary – Myocarditis
Published: September 2021 • Last updated: April 2023
- PARA-aligned, reviewed February 2026
PASSMAP ensures all content is NICE-aligned and reviewed for Physician Associate Registration Assessment (PARA) success.
Educational platform. Not medical advice.