Nitroglycerin in Right Ventricular Infarction
Nitroglycerin should be used with extreme caution, if at all, in patients with suspected right ventricular infarction due to the high risk of profound, life-threatening hypotension. 1
Critical Pathophysiology
Right ventricular infarction creates a unique hemodynamic situation where cardiac output becomes critically dependent on adequate right ventricular preload to maintain left ventricular filling. 1 Nitroglycerin's primary mechanism—venous dilation and preload reduction—directly undermines this compensatory mechanism, leading to precipitous drops in cardiac output and blood pressure. 2
Clinical Approach
Before Administering Any Nitrate
- Obtain a right-sided ECG (V3R-V4R) in all patients with inferior STEMI to evaluate for right ventricular involvement before considering nitrates. 3
- Check systolic blood pressure—nitrates are contraindicated if SBP <90 mmHg or ≥30 mmHg below baseline. 2, 3
- Assess for clinical signs of RV infarction: hypotension, clear lung fields, elevated jugular venous pressure (the classic triad). 1
If RV Infarction is Suspected or Confirmed
The guideline recommendation is clear: avoid nitroglycerin entirely or use only with extreme caution. 1, 2 The American College of Cardiology explicitly states these patients "can experience profound hypotension during nitrate administration." 1
The Single Exception
If you must attempt nitroglycerin despite suspected RV involvement (e.g., severe ongoing ischemic pain with SBP >90 mmHg):
- Ensure IV access is established first. 3
- Consider a single sublingual nitroglycerin tablet (0.4 mg) only in the hospital setting with continuous monitoring. 3
- Have immediate access to IV fluids, leg elevation capability, and atropine. 1
- Do not proceed with IV nitroglycerin infusion. 1
Management of Nitroglycerin-Induced Hypotension in RV Infarction
If hypotension occurs after nitrate administration:
- Discontinue nitroglycerin immediately. 2
- Elevate legs to increase venous return. 1, 2
- Administer rapid IV fluid bolus (500-1000 mL normal saline). 1
- Give atropine if associated bradycardia is present. 1, 2
Alternative Pain Management
Instead of nitroglycerin in RV infarction patients:
- Administer aspirin 162-325 mg (chewed) if no contraindications. 3
- Use morphine sulfate 2-4 mg IV for pain relief. 3
- Focus on early reperfusion therapy, which provides the most effective pain relief by addressing ongoing ischemia. 1
Common Pitfall
The most dangerous error is administering nitrates to patients with inferior wall MI without first ruling out RV involvement. Inferior MI is frequently associated with RV infarction, making the right-sided ECG a mandatory step before nitrate administration in this population. 1, 3 The FDA label itself warns about careful hemodynamic monitoring in acute MI due to hypotension risk. 4