Right ventricular myocardial infarction resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

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

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

References

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