The classification of troponin elevation in the absence an acute platelet mediated coronary occlusion remains a vexing clinical challenge. Our recent poll described a patient with nonischemic cardiomyopathy presenting with progressive respiratory distress, pulmonary edema, and mildly elevated troponin levels rising over a 3-hour period. Most respondents (60%) selected the diagnosis of acute myocardial injury related to heart failure. The second most popular answer was type 2 non-ST-segment elevation myocardial infarction, selected by a quarter of respondents. About 10% diagnosed chronic myocardial injury related to heart failure, and 5% diagnosed type 1 non-ST-segment elevation myocardial infarction. According to the Fourth Universal Definition of Myocardial Infarction, acute myocardial injury is characterized by the rise and/or fall of cardiac troponin levels with at least one value above the 99th percentile upper reference limit. If myocardial injury is thought to be secondary to ischemia due to an imbalance in myocardial oxygen supply and demand unrelated to coronary thrombosis, the diagnosis of type 2 myocardial infarction can be made.

Clinical Topics: Acute Coronary Syndromes, Heart Failure and Cardiomyopathies, Stable Ischemic Heart Disease, Acute Heart Failure

Keywords: Acute Coronary Syndrome, Myocardial Reperfusion Injury, Troponin, Myocardial Infarction, Coronary Thrombosis, Coronary Occlusion, Pulmonary Edema, Respiratory Distress Syndrome, Myocardium, Heart Failure, Cardiomyopathies

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