Clinical Inquiries. How accurate is the use of ECGs in the diagnosis of myocardial infarct?

The electrocardiogram (ECG) is a fairly accurate test in the diagnosis of myocardial infarction (MI). However, given more sensitive technologies, such as cardiac biomarker testing, its primary role should be as an important adjunct in the evaluation and detection of MI (strength of recommendation [SOR]: A). The sensitivity of ECG for detection of MI is directly related to what is defined as positive findings on the ECG for MI. The single most specific ECG finding is the presence of new ST segment elevation of at least 1 mm (SOR: A). Other findings such as the development of new pathologic Q waves and ST depression can also be valuable in making the diagnosis.