Right ventricular myocardial infarction resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Mitra Chitsazan, M.D.[2] Mandana Chitsazan, M.D. [3]

Overview

RV infarction is a form of ST elevation myocardial infarction (STEMI) and is characterized by the presence of symptoms of myocardial ischemia associated with persistent ST elevation on electrocardiogram in right sided lead V4, and elevated cardiac enzymes, hypotension, signs of elevated right heart filling pressures (elevated neck veins) in the absence of signs of elevated left heart filling pressures (clear lung fields). Nitrates, diuretics and beta-blockers should not be administered to the patient with an RV MI.

Causes

Life Threatening Causes

STEMI is a life-threatening condition and must be treated as such irrespective of the underlying cause.

Common Causes

• Plaque rupture
• Aortic dissection with propagation to the right coronary artery
• Cocaine

Management

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 1-2L, 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.

References

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