What to give to a patient with inferior myocardial infarction (MI) and right ventricular infarction (RVI) presenting with hypotension?

Management of Hypotension in Inferior MI with Right Ventricular Infarction

Volume expansion with IV normal saline is the first-line treatment for hypotension in patients with inferior MI complicated by right ventricular infarction. 1, 2

Pathophysiology and Clinical Recognition

Right ventricular infarction (RVI) complicates 30-50% of inferior MIs and creates a unique hemodynamic situation:

• RV dysfunction reduces left ventricular preload, causing hypotension
• The classic triad (though only 25% sensitive) includes:
  • Hypotension
  • Clear lung fields
  • Elevated jugular venous pressure 1
• Diagnosis is confirmed by:
  • ST elevation ≥1mm in right precordial lead V4R (highly predictive) 1, 3
  • Echocardiography showing RV dilation and dysfunction 2

Treatment Algorithm

1. Initial Volume Resuscitation

• Administer IV normal saline bolus (2000-2500 mL) followed by infusion at 500 mL/h 2
• Target right atrial pressure of ≥10 mmHg or 80% of pulmonary wedge pressure 1
• Monitor response using blood pressure, urine output, and peripheral perfusion 2

2. If Hypotension Persists After Adequate Volume Loading

• Add inotropic support with dobutamine (starting at 2.5 μg/kg/min, increasing up to 10 μg/kg/min) 1, 2
• For renal hypoperfusion, consider dopamine (2.5-5.0 μg/kg/min) 1
• For severe persistent hypotension, consider norepinephrine to maintain systolic BP 80-100 mmHg 2, 4

3. Maintain Atrioventricular Synchrony

• Use AV sequential pacing for symptomatic high-degree heart block unresponsive to atropine 1, 2
• Prompt cardioversion for hemodynamically significant supraventricular tachycardias 1

4. Arrange Urgent Reperfusion Therapy

• Primary percutaneous coronary intervention is preferred 2, 5
• Reperfusion facilitates RV recovery, even after prolonged occlusion 5

Critical Interventions to Avoid

• Do not administer nitrates, morphine, or diuretics as they reduce preload and can cause profound hypotension 1, 2
• Avoid vasodilators that may worsen hypotension 1

Monitoring and Additional Support

• Consider pulmonary artery catheterization for refractory cases to guide therapy 1, 2
• For persistent shock despite optimal medical therapy, consider mechanical circulatory support:
  • Intra-aortic balloon pump 1, 6
  • Right ventricular assist devices in severe cases 7, 5

Prognosis

• RVI has high in-hospital mortality (25-30%) compared to uncomplicated inferior MI 1, 8
• However, patients who survive hospitalization typically show good recovery of RV function over weeks to months, suggesting RV stunning rather than irreversible necrosis 1, 5

Remember that early recognition and prompt volume resuscitation are crucial for improving outcomes in patients with inferior MI complicated by RV infarction and hypotension.