Sandbox:Mitra

Therapuetic Considerations in Right Ventriculay Myocardial Infarction (RVMI)

Reperfusion

Maintenance of RV preload

Decreasing RV afterload

Restoring Rate/Rhythm and AV synchrony

Inotropic support

Mechanical Circulatory Support

Thrmobolytics Percutaneous coronary intervention (PCI)

• Avoidance of preload-reducing agents, such as: ❑ Nitrates ❑ Diuretics ❑ Morphin • In patients with hypotension (without pulmonary congestion): ❑ Intravenous administration of Fluids (N/S 0.9% at 40mL/min for up to 2L, to maintain CVP <15 mmHg and PCWP between 18-24 mmHg)

• Systemic or pulmonary vasodilators: ❑ Nitrosrusside ❑ Inhaled nitric oxide

• In patients with bradyarrhthmias: ❑ Atropine ❑ Pacemaker • In patients with atrioventricular block: ❑ Temporary dual-chamber pacemaker

In patients with refractory hypotension: ❑ Dobutamine (along with fluids) ❑ Other inotropes: Milrinone Norepinephrine

• May be needed in patients with cardiogenic shock secondary to RVMI: ❑ Direct RV support ❑ Indirect RV support ❑ Biventricular support

Do's

• Right ventricular myocardial infarction (RVMI) should be ruled out in all patients presenting with acute inferior wall myocardial infarction, in particular in patients with hypotension.

• In patients presenting with chest pain and clinical findings of hypotension, elevated JVP and clear lung fields, consider the differential diagnoses of RVMI. These include:
  • Pulmonary embolism
  • Pericarditis with pericardial tamponade

• Systemic or pulmonary vasodilators may be considered in selected patients to reduce RV afterload, thereby improving cardiac output.

• In patients with severe tricuspid regurgitation due to RVMI, replacement of tricuspid valve or repair of the valve with annuloplasty rings may be considered.

• In patients with RVMI who have unexplained hypoxemia despite administration of 100% oxygen, right-to-left shunting -through a patent foramen ovale or atrial septal defect-, caused by the disproportionate elevation in right-sided filling pressures compared to the normal or slightly increased left-sided filling pressures should be considered.

• Patients with extensive necrosis due to RVMI may be at higher risk of right ventricular perforation during interventional procedures. Right ventricular catheterization or pacemaker insertion should be performed with great care in these patients.

Don'ts

• In patients with RVMI, avoid preload-reducing agents such as nitrates, diuretics, morphine, beta-blockers, and calcium channel blockers.

Previously:

Consider right ventricular MI in case of: ❑ Hypotension ❑ Elevated jugular venous pressure ❑ Clear lung fields ❑ ECG changes suggestive of an inferior MI ❑ ST elevation in leads II, III and aVF
Order a right sided ECG in all patients with ST elevation in leads II, III and aVF ❑ Clearly label the ECG as right sided to minimize confusion in the emergency room and cath lab ❑ ST-segment elevation of >1 mm in lead V4R suggests a right ventricular MI
❑ Do not delay the decision and initiation of PCI vs fibrinolytic therapy ❑ Do not administer: ❑ Beta blockers ❑ Nitrates ❑ Diuretics ❑ Increase the right ventricle load by volume expansion with normal saline preferably with invasive monitoring ❑ If central hemodynamic monitoring is available, administer normal saline (40 ml/min, up to a total of 2 L, intravenously) until there is an increase in the pulmonary capillary wedge pressure to approximately 15 mmHg ❑ If central hemodynamic monitoring in not available, administer normal saline with a close monitoring of the blood pressure
If hypotension is not corrected with 1-2 L normal saline: ❑ Administer inotropic agents ❑  Norepinephrine ❑  Initial dose: 0.5–1.0 μg/min ❑  Maximum dose: 30–40 μg/min ❑  Titrate to SBP >90 mm Hg ❑  Dopamine ❑  Cardiac dose: 5.0–10 μg/kg/min ❑  Pressor dose: 10–20 μg/kg/min ❑  Maximum dose: 20–50 μg/kg/min ❑  Dobutamine ❑  Usual dose: 2.0–20 μg/kg/min ❑  Maximum dose: 40 μg/kg/min ❑  Avoid ↑ HR by >10% of baseline ❑  Milrinone ❑  Loading dose: 50 μg/kg (slowly over 10 minutes) ❑  Maintenance dose: 0.375–0.75 μg/kg/min ❑ Initiate hemodynamic monitoring with a pulmonary catheter if possible