Differentiating ischemia, injury, infarction: expanding the 12-lead electrocardiogram.

In 50% of cases of myocardial infarction, the 12-lead electrocardiogram (ECG) is not diagnostic of the infarction. Critical care nurses, aware of subtle ECG changes coupled with patient complaint of chest pain, may improve recognition of myocardial infarction. Expanding the 12-lead ECG to include right ventricular precordial leads and posterior chest leads facilitates recognition of right ventricular infarction and posterior wall infarction not recognized on the standard 12-lead ECG.