Cardiomyopathies and myocarditis

Cardiomyopathies and myocarditis are frequently challenging in clinical practice regarding differentiation, risk stratification and treatment strategy. There are various disease entities which often affect young or middle-aged adults and the course is variable from asymptomatic and irrelevant for prognosis to sudden cardiac death or severe heart failure even at an early age. Making the right diagnosis is therefore fundamental to correctly identify affected patients and to initiate treatment steps in time. Whereas causal treatment options exist for some forms of cardiomyopathy, the majority of patients receives standard heart failure and device therapy but others require lifelong careful monitoring. The diagnosis of cardiomyopathy is mainly based on the cardiac phenotype; therefore, non-invasive imaging is very important. Cardiovascular magnetic resonance has become the gold standard to assess cardiomyopathy as it combines functional information (e.g. wall motion) with myocardial tissue analysis (e.g. fibrosis and edema) and in some cases it can replace invasive endomyocardial biopsies. The importance of cardiovascular magnetic resonance to assess cardiomyopathy is based on several aspects: accurate analysis of cardiac dimensions and function, non-invasive tissue analysis to make the diagnosis (e.g. myocarditis), estimation of prognosis by non-invasive tissue analysis, high reproducibility for accurate follow-up examinations, potential for technical improvements (e.g. quantification of extracellular volume fraction by T1 mapping). In all types of cardiomyopathy, cardiovascular magnetic resonance has a major impact on the differential diagnosis, risk stratification and treatment. In some entities the appropriate clinical use is already confirmed by evidence (e.g. myocarditis) and in others there are first encouraging results that indicate the future potential (e.g. risk stratification in hypertrophic cardiomyopathy). Cardiovascular magnetic resonance has evolved as the gold standard to assess cardiomyopathy as it provides both functional and morphological information. It is recommended to use this technique in a comprehensive approach to achieve complete work-up of affected patients.