Table 2.

Modified International Cardio-Oncology Society 2021 consensus for the diagnosis of immune checkpoint inhibitor myocarditis

Either a pathohistological diagnosis:

Multifocal inflammatory cell infiltrates with overt cardiomyocyte loss by light microscopy on cardiac tissue samples

Or a clinical diagnosisa,b:

A troponin elevation (new, or significant change from baseline) with one major criterion or a troponin elevation (now, or significant change from baseline) with two minor criteria after exclusion of acute coronary syndrome or acute infectious myocarditis based on clinical suspicion

Major criterion

Cardiac MRI diagnostic for surto myocarditis (modified Lake Louise criteria)

Minor criteria

Clinical syndrome (including any one of the following: fatigue, muscle weakness, myalgias, chest pain, diplopia, ptosis, shortness of breath, orthopnoea, lower extremity oedema, palpitations, lightheadedness/dizziness, syncope, cardiogenic shock)

Ventricular arrhythmia and/or new conduction system disease

Decline/reduction in cardiac systolic function, with or without regional wall motion abnormalities in a non-Takotsubo pattern

Other immune-related adverse events, particularly myositis, myopathy, myasthenia gravis

Suggestive cardiac MRI (meeting some but not all the modified Lake Louise criteria)

Suggestive cardiac pathology (multifocal inflammatory all infiltrates without overt cardiomyocyte loss by light microscopy on cardiac tissue samples)

Both Troponin I and Troponin T can be used; however, Troponin T may be falsely elevated in those with concomitant myositis.

^aThe clinical diagnoses should be confirmed with cardiac MRI or endomyocardial biopsy if possible and without causing delays of treatment.

^bIn a patient who is clinically unwell, treatment with immunosuppression should be promptly initiated while awaiting further confirmatory testing.