Unlike a standard 12-lead electrocardiogram (ECG), used primarily to evaluate left ventricular function, a right chest lead ECG reflects right ventricular function and provides clues to damage or dysfunction in this chamber. You might need to perform a right chest lead ECG for a patient with an inferior wall myocardial infarction (MI) and suspected right ventricular involvement. Between 25% and 50% of patients with this type of MI have right ventricular involvement.

Early identification of a right ventricular MI is essential because its treatment differs from treatment for other MIs. For instance, in left ventricular MI, treatment involves administering IV fluids judiciously to prevent heart failure. Conversely, in right ventricular MI, treatment typically requires administration of IV fluids to maintain adequate filling pressures on the right side of the heart. This helps the right ventricle eject an adequate volume of blood at an adequate pressure.