Type 2 myocardial infarction: poorly understood, under-evaluated, and too often ignored

Type 2 myocardial infarction (T2MI) is caused by ischemia from reduced oxygen supply, increased demand, or both, without acute atherothrombosis. Multiple nonatherosclerotic factors can reduce myocardial oxygen supply, including coronary pathology such as vasospasm, dissection, or embolism, as well as noncoronary processes such as anemia, hypoxemia, and hypotension. Similarly, multiple factors increase oxygen demand including severe hypertension, tachycardia, and fever. Furthermore, T2MI can occur in patients with or without obstructive coronary artery disease (CAD). In those without obstructive CAD, the magnitude of supply-demand mismatch necessary to cause ischemic necrosis is much higher. While an extensive evidence base guides the evaluation and treatment of type 1 myocardial infarction (T1MI), which is caused by acute plaque disruption and secondary thrombosis, few high-quality studies exist for T2MI.