Heart Muscle Inflammation (Myocarditis): Diagnostic Tests

Obligatory medical device diagnostics.

  • Electrocardiogram (ECG; recording of the electrical activities of the myocardium) – as a standard diagnostic test [“infarct-like” ECG changes, especially ST-segment depression; T-negativations; conduction disturbances and extrasystoles] Note: ST-segment changes or T-negativations are detectable in less than 50% of patients in the early stages of myocarditis.
  • Echocardiography (echo; cardiac ultrasound)-as a standard diagnostic test or to rule out other causes of new-onset heart failure symptomsNote: Mild courses of myocarditis are associated with unremarkable echocardiography.
  • Magnetic resonance imaging (MRI; computer-assisted cross-sectional imaging (using magnetic fields, i.e., without X-rays)), i.e., cardiac magnetic resonance imaging, native or contrast-enhanced – for differential diagnostic questions to assess morphologic and functional changes (right and left ventricular function) and to detect inflammatory (inflammation-related) changes in myocardial (heart muscle) tissue [method of choice in the diagnosis of myocarditis].
  • X-ray of the thorax (X-ray thorax/chest), in two planes – to determine myocardial size (heart muscle size).

Optional medical device diagnostics – depending on the results of the history, physical examination and mandatory laboratory parameters – for differential diagnostic clarification.

  • 24h ECG/long-term ECG
  • Endomyocardial biopsy (right and/or left heart catheterization with biopsy collection (tissue sampling) from the inner layer of the heart muscle (endomyocardium) for histopathologic, immunohistologic, and molecular biology tissue analysis; see classification below: Dallas criteria).
    • In V. D. for myocarditis with impaired cardiac function or for diagnosis of definite myocarditis [gold standard].
    • Heart failure patients (cardiac insufficiency) with dilated left ventricle (dilated left ventricle) and ventricular arrhythmias or AV block II or III degree (history duration: 2 weeks – 3 months) [Class I indication].

    Procedure (procedure): removal of 5-10 biopsies (size 1-2 mm3 each) from more than one region of the right ventricular septum (partition between the left and right main chambers (ventricles) of the heart; right ventricular means “affecting the right ventricle“).

  • Cardiac catheterization – for differential diagnostic clarification.

Further notes

  • In the diagnosis of myocarditis, neither ECG changes nor an increase in cardiac enzymes by themselves have diagnostic value!