Myocardial Infarction Type 2 and Myocardial Injury

BACKGROUND: The development and implementation of sensitive and high-sensitivity cardiac troponin assays has not only expedited the early ruling in and ruling out of acute myocardial infarction, but has also contributed to the identification of patients at risk for myocardial injury with necrosis, as confirmed by the presence of cardiac troponin concentrations above the 99th percentile. Myocardial injury with necrosis may occur either in the presence of overt ischemia from myocardial infarction, or in the absence of overt ischemia from myocardial injury accompanying other conditions. Myocardial infarction type 2 (T2MI) has been a focus of attention; conceptually T2MI occurs in a clinical setting with overt myocardial ischemia where a condition other than an acute atherothrombotic event is the major contributor to a significant imbalance between myocardial oxygen supply and/or demand. Much debate has surrounded T2MI and its interrelationship with myocardial injury. CONTENT: We provide a detailed overview of the current concepts and challenges regarding the definition, diagnosis, management, and outcomes of T2MI, as well as the interrelationship to myocardial injury, and emphasize several critical clinical concepts for both clinicians and researchers moving forward. SUMMARY: T2MI and myocardial injury are frequently encountered in clinical practice and are associated with poor outcomes in both the short term and long term. Diagnostic strategies to facilitate the clinical distinction between ischemic myocardial injury with or without an acute atheroma-thrombotic event vs non-ischemic-mediated myocardial injury conditions are urgently needed, as well as evidence-based therapies tailored toward improving outcomes for patients with T2MI.