Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
Rapidmyocarditismyopericarditiscardiac MRIendomyocardial biopsycardiogenic shockventricular arrhythmiaimmune-checkpoint inhibitorreturn to exercise
Myocarditis
Essential points for quick revision.
2 min synopsisUK scopeSources checked 27 Aug 2026Clinical review pending
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Escalate
Suspected myocarditis with shock, rapidly worsening heart failure, cardiac arrest, sustained ventricular arrhythmia, syncope, high-grade AV block or severe new ventricular dysfunction needs monitored admission and immediate discussion with a tertiary myocarditis and advanced-heart-failure service. Stabilisation, coronary exclusion and mechanical-support planning must not wait for a complete diagnostic work-up.
Synopsis
Recognise suspected myocardial inflammation, exclude coronary and other urgent mimics, select CMR or endomyocardial biopsy appropriately, stabilise haemodynamic and electrical complications, and plan cause-specific treatment, activity restriction and follow-up.
Myocarditis may look like acute coronary syndrome, decompensated heart failure, an arrhythmia or an unexplained conduction disorder; a recent viral illness is neither required nor diagnostic.
Use ECG, continuous rhythm observation when risk is significant, serial troponin, inflammatory markers, natriuretic peptide and transthoracic echo to establish injury and severity, not to assign a viral cause.
Do not label a troponin-positive chest-pain presentation as myocarditis until acute coronary occlusion has been assessed according to the patient's age, risk, ECG, instability and clinical probability.
Key red flags
Infarct-like presentation
Acute chest pain, ST-T change and troponin elevation may be indistinguishable from acute coronary syndrome at first contact. Pleuritic pain or a recent infection can support the history but cannot safely exclude coronary occlusion.
Investigation priorities
01
Immediate observations, ECG and rhythm monitoringFirst step
Identify ischaemia, ventricular arrhythmia, AV block and haemodynamic instability and establish whether a monitored setting is required.
Management branches
First contactRecognise risk and exclude coronary disease
Chest pain, troponin elevation, new ventricular dysfunction, arrhythmia or conduction disease with suspected myocardial inflammation.
Perform ABCDE assessment, 12-lead ECG, serial observations and troponin, targeted bloods and urgent TTE; use telemetry when syncope, conduction disease, ventricular arrhythmia or significant dysfunction is present.
Activate the acute coronary syndrome pathway when coronary occlusion remains plausible. Select invasive or CT coronary assessment from the patient's risk and stability rather than from the presence of a viral history.
RecoveryProtect the ventricle and plan return to activity
The patient is haemodynamically stable and acute injury is resolving.
Key medicines
Disease-modifying HFrEF treatment after myocarditisThere is no myocarditis-specific class dose. Once shock has resolved and the patient is haemodynamically stable, select and titrate each indicated medicine using NICE NG106, the current product SmPC and the dedicated HFrEF chapter.
Immunosuppression for defined immune-mediated myocarditisNo single empirical adult regimen is safe. The tertiary team should use the subtype-specific 2025 ESC protocol, pathology and infection assessment, patient weight and organ function to prescribe and document the exact regimen.
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.