American Association of Critical-Care Nurses (AACN) Certification Practice Test

In which type of myocardial infarction should nitroglycerin be used cautiously?

1. Anterior wall MI

2. Inferior wall MI

3. Lateral wall MI

4. Posterior wall MI

The correct answer is: Inferior wall MI

Nitroglycerin should be used cautiously in the case of inferior wall myocardial infarction (MI) primarily due to the potential for hypotension and the associated risk of right ventricular involvement. In inferior wall MIs, especially those caused by occlusion of the right coronary artery, there is a risk of right ventricular MI developing. This condition can lead to significant preload dependence because the right ventricle relies heavily on adequate filling pressures to maintain cardiac output. Administering nitroglycerin, which is a vasodilator, may lead to decreased preload and exacerbation of hypotension in patients with right ventricular MI. This can potentially compromise cardiac output and worsen the patient’s hemodynamic status. Therefore, clinicians often proceed with caution regarding nitroglycerin use in inferior wall MIs and will closely monitor the patient’s blood pressure and overall condition. In contrast, in other types of myocardial infarctions, such as anterior, lateral, or posterior wall MIs, the risks associated with nitroglycerin do not involve the same level of concern regarding right ventricular function, making it safer to use in those situations when closely monitored.