To the Editor.
—Two points of concern in the article by Dr Guest and colleagues1 on detecting myocardial injury in critically ill patients using cardiac troponin I raise doubts about the usefulness of this study.First, in the "Methods" section the authors state, "Patients who met criteria for cardiac injury based on cardiac troponin I levels who were not diagnosed with acute myocardial infarction by the ICU [intensive care unit] team were classified as having unrecognized myocardial injury. Diagnoses of acute infarction made by the ICU team that were not confirmed by elevated levels of cardiac troponin I were considered false-positive diagnoses." This operational definition of myocardial injury implies two conclusions: that cardiac troponin I is 100% sensitive and 100% specific and/or that clinicians at the institution have difficulty diagnosing myocardial infarction using currently established tools (by diagnosing myocardial infarction in four patients in whom cardiac troponin I was
Beck SR. Myocardial Injury in Critically III Patients. JAMA. 1995;274(21):1672. doi:10.1001/jama.1995.03530210026015