AKT · Cardiovascular/Failure & myocardium

Myocarditis

Inflammation of the myocardium — usually viral (Coxsackie, parvovirus, SARS-CoV-2)

Overview

Inflammation of the heart muscle, most often post-viral, but also drug/toxin-related, autoimmune or due to immune-checkpoint inhibitors. Presents with chest pain, heart failure or arrhythmia after a viral prodrome, often with a raised troponin and normal coronaries — a key ACS mimic. Can cause fulminant heart failure and is a leading cause of sudden death and dilated cardiomyopathy in the young.

Recognise

Recent viral prodrome (fever, myalgia, coryza) then chest pain, breathlessness, palpitations or syncope
Raised troponin and inflammatory markers with non-specific/ST-T changes and UNOBSTRUCTED coronary arteries
May progress to heart failure, ventricular arrhythmia or dilated cardiomyopathy

Red flags

Fulminant myocarditis (cardiogenic shock, ventricular arrhythmia, high-grade block) → ICU/mechanical support
Immune-checkpoint-inhibitor myocarditis → stop the drug, high-dose steroids — high mortality

Differentials & how to tell them apart

Acute coronary syndromeobstructive coronary disease on angiography; myocarditis has normal coronaries

Pericarditispleuritic positional pain, diffuse saddle ST elevation, pericardial rub (often overlaps as myopericarditis)

Takotsubo cardiomyopathyapical ballooning after stress, normal coronaries

Investigations

Troponin (raised) and inflammatory markers; ECG; echo (regional/global dysfunction); cardiac MRI (myocardial oedema/late gadolinium — the key non-invasive test); coronary angiography to exclude ACS; viral/autoimmune work-up; endomyocardial biopsy if fulminant/unexplained.

Management

Supportive HF therapy + treat the cause; avoid exercise during recovery

1Raised troponin + viral prodrome + unobstructed coronaries → suspect myocarditis; confirm with cardiac MRI and exclude ACS by angiography.Gate: Fulminant disease (shock, ventricular arrhythmia, high-grade block) → ICU and mechanical circulatory support; checkpoint-inhibitor myocarditis → stop the drug + high-dose steroids.
2Supportive heart-failure and arrhythmia therapy, treat/remove the cause, and advise exercise restriction during recovery; immunosuppression for specific autoimmune forms.

Supportive heart-failure therapy — treat heart failure/arrhythmia per standard guidance; rest and avoid strenuous exercise during recovery

Treat the cause — stop the offending drug; immunosuppression for autoimmune/checkpoint-inhibitor or biopsy-proven giant-cell myocarditis

Mechanical support/transplant — for fulminant disease

Key points

Young patient, viral prodrome, chest pain with raised troponin but NORMAL coronaries = myocarditis (cardiac MRI confirms) — a key ACS mimic. Rest during recovery; fulminant disease needs ICU support.

Monitor & prognosis

Serial troponin/echo, arrhythmia surveillance, recovery of LV function on MRI.

Often recovers fully; fulminant or giant-cell forms have high mortality; can lead to DCM.

Source: ESC; cross-ref acute_care