Cardiovascular Magnetic Resonance for Myocardial Inflammation: Lake Louise Versus Mapping?

See Article by Pan et al Myocardial inflammation is a nonspecific response to viruses, autoantibodies, toxic substances, catecholamine surge, radiation, or mechanical injury. It can be safely assumed that it is a fairly common event, luckily with a mostly benign course and outcome. Myocarditis, however, is a frequent cause for acute myocardial injury in patients with no explanatory coronary artery stenosis1 and has repeatedly been identified as an important cause of sudden death in the young.2,3 The clinical diagnosis of myocarditis is challenging because of the wide spectrum of often atypical symptoms. The 2013 European Society of Cardiology position statement suggests establishing a clinical diagnosis of myocarditis based on the clinical criteria of new-onset dyspnea, palpitations, or chest discomfort in the presence of myocardial damage that is not explained by coronary artery disease.4 These symptoms, however, are not specific to myocardial inflammation and may, for example, also occur in acutely exacerbated heart failure. Over the recent decades, cardiovascular magnetic resonance (CMR) with its ability to identify inflammatory tissue characteristics has been more and more widely used as the prime imaging tool in patients with suspected acute myocarditis. By including CMR in the diagnostic workup of these patients, the diagnostic yield can be improved above that of clinical criteria alone,5 and the subsequently observed incidence of myocarditis was recently found to be increased >6-fold.6 The current clinical application of CMR has been based on the recommendations of an international consensus group with diagnostic criteria that target tissue inflammation, also known as Lake Louise Criteria (LLC).7 Using 2 out of 3 positive criteria for myocardial …