From the Guidelines
ACE inhibitors should be avoided in right ventricular infarcts because they can cause dangerous hypotension in these patients. Right ventricular infarcts result in impaired right ventricular filling, which makes these patients particularly dependent on adequate preload (venous return to the heart) to maintain cardiac output. According to the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1, nitrates are contraindicated in patients with right ventricular infarction, and caution is advised in patients with known inferior wall STEMI, due to the risk of reducing RV preload. Similarly, ACE inhibitors dilate blood vessels and reduce preload, which can critically lower blood pressure in these patients whose cardiac function already relies heavily on adequate venous return. This preload reduction can lead to profound hypotension, decreased cardiac output, and even cardiogenic shock. Instead, management of right ventricular infarcts typically focuses on:
- Maintaining adequate fluid status with IV fluids to optimize preload
- Using dobutamine if needed for inotropic support
- Avoiding medications that reduce preload or systemic vascular resistance Once the patient has stabilized and right ventricular function has improved, ACE inhibitors may be reconsidered as part of standard post-MI care, but this should be done cautiously with close hemodynamic monitoring, as recommended by the guidelines 1.
From the FDA Drug Label
CONTRAINDICATIONS Lisinopril is contraindicated in patients who are hypersensitive to this product and in patients with a history of angioedema related to previous treatment with an angiotensin converting enzyme inhibitor and in patients with hereditary or idiopathic angioedema. The FDA drug label does not answer the question.
From the Research
Right Ventricular Infarcts and ACE Inhibitors
- The use of ACE inhibitors in right ventricular infarcts is a complex issue, with several studies providing insights into the pathophysiology and management of this condition 2, 3, 4.
- Right ventricular infarction is associated with higher in-hospital morbidity and mortality, and is often complicated by hemodynamic compromise, cardiogenic shock, and electrical complications 2, 3, 4.
- The right ventricle is relatively resistant to infarction and usually recovers even after prolonged occlusion, but ACE inhibitors may not be beneficial in the acute phase of right ventricular infarction 5.
- In fact, the use of ACE inhibitors in the acute phase of myocardial infarction has been shown to decrease survival rates in some studies, highlighting the importance of timing and patient selection 5.
Pathophysiology of Right Ventricular Infarcts
- Right ventricular infarction is often caused by an acute occlusion of a dominant right coronary artery or left anterior descending artery, leading to depressed RV systolic function and diminished transpulmonary delivery of left ventricular preload 2, 3.
- The right ventricle is dependent on left ventricular-septal contraction via paradoxical septal motion, and augmented right atrial contraction can optimize RV performance 2, 3.
- However, very proximal occlusions can induce right atrial ischemia, exacerbating hemodynamic compromise 2, 3.
Management of Right Ventricular Infarcts
- The management of right ventricular infarction involves identifying specific clinical signs and symptoms, initiating resuscitation, and commencing reperfusion therapy with fibrinolytic therapy or percutaneous coronary intervention 4.
- Volume resuscitation and restoration of a physiologic rhythm may be beneficial in hypotensive patients, while refractory cases may require parenteral inotropes or mechanical support 2, 3.
- ACE inhibitors may be beneficial in patients with left ventricular dysfunction, but their use in right ventricular infarction is not well established and requires further study 5, 6.