Type 2 Myocardial Infarction: A Grim Diagnosis with Different Shades of Gray

Type 2 myocardial infarction (MI) is commonly encountered in daily practice. Its incidence can range between 5 and 35% among all cases of MI. It is caused by disorders that result in supply-demand mismatch, which leads to myocardial ischemia and necrosis. Therefore, unsurprisingly, it is frequently diagnosed in critically ill patients and those with severe coronary artery disease (CAD) and multiple comorbidities. Though it can occur in the absence of CAD, the presence of coronary blood flow-limiting stenoses can allow even minor insults to disturb the already fine supply-demand balance. Generally, type 2 MI may be associated with higher mortality; however, some data suggest it may have different severities, and outcome is better in patients with type 2 MI of milder severity. Nonetheless, regardless of the causes (ischemic or nonischemic), troponin elevation is associated with worse outcome. Differentiating type 2 MI from other causes of myocardial necrosis, mainly type 1 MI and myocardial injury, remains a clinical challenge.

Different diagnostic tools can be utilized to aid in reaching an accurate diagnosis. These can include contrast echocardiography, computed tomography, MRI, radionuclide imaging, coronary angiography, and intracoronary imaging. However, each comes with its own limitations and results should be interpreted with caution and in clinical context. Management of type 2 MI is uncertain because of paucity of data. Evidence-based therapies of type 1 MI are frequently used, though this may be harmful sometimes. Therefore, clinical judgment should be used, and management and therapies should be tailored to each individual case.