Table 5.

Recommendation for advanced diagnostic workup: endomyocardial biopsy and cardiac magnetic resonance imaging

Endomyocardial biopsy	Cardiac magnetic resonance imaging (CMR)
Acute myocarditis with acute heart failure or cardiogenic shock	CMR scans should be performed for clinical indications according to recent publications on the condition 60 , 61 , 67
Acute myocarditis with ventricular arrhythmias or high‐degree atrioventricular block	Protocols should be adjusted to the clinical scenario, but generally should include standard CINE imaging, T2 (e.g. STIR) oedema imaging, T2 mapping (e.g. T2‐GraSE), pre‐ and post‐contrast T1 mapping (e.g. MOLLI), and late enhancement imaging (e.g. mDIXON). 62 If possible, strain analysis should be performed (based on feature tracking or fSENC/ DENSE)
Acute myocarditis or chronic inflammation in the context of peripheral eosinophilia	Vasodilator stress CMR with adenosine or regadenoson may be performed in patients with suspected myocardial ischaemia (e.g. microvascular disease), but should be avoided in the acute stage, particularly in more severe forms
Acute myocarditis or dilated cardiomyopathy suspected as chronic inflammatory cardiomyopathy with continuous/recurrent release of inflammatory and cardiac markers	CMR image analysis and measurements should be performed using dedicated CMR post‐processing software 68
When diagnosis has an impact on further therapy	The definite CMR diagnosis of acute myocarditis should be based on the updated ‘Lake Louise Criteria’ requiring findings of myocardial damage (non‐ischaemic late gadolinium enhancement) and oedema with a non‐ischaemic pattern 60