How Massive PE Kills – A Review of Right Heart Failure

November 16, 2022

Written by Laura Murphy

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Decompensated right heart failure (RHF) increases morbidity and mortality, but it can be challenging to diagnose and treat. This review summarizes the unique physiology of RHF and treatment implications.

Why does this matter?
These patients are walking a razor’s edge. You need to be able to diagnose, assess, and treat this life-threatening condition.

Try to get it right
RHF is impaired right ventricular (RV) contractility due to myocardial dysfunction, elevated pulmonary pressures, or volume overload. The most common cause is left heart failure, followed by chronic lung disease, thromboembolism, or pulmonary arterial hypertension. The RV is thin-walled compared to the left ventricle and is more sensitive to changes in afterload (pulmonary vascular resistance) or decreased perfusion due to systemic hypotension or elevated RV pressure. In acute RHF, the RV is preload-dependent to maintain stroke volume, but volume overload can lead to RV distension and bowing of the LV septum, decreasing cardiac output (ventricular interdependence).  The cyclic pathophysiology of right heart failure is demonstrated below.

Treatment should target the underlying cause while optimizing hemodynamics and oxygenation. POCUS is particularly important in RHF to assess RV function and determine volume status.

• Systemic hypotension can be due to hypovolemia or volume overload with RV overdistension, so use POCUS to determine need for additional fluids vs diuresis. Titrate fluids slowly (250 cc at a time), and use vasopressors (norepinephrine) early in the hypotensive patient.
• Avoid hypoxia and acidosis, which worsen pulmonary vasoconstriction and increase afterload. Consider pulmonary vasodilators (inhaled nitric oxide or phosphodiesterase inhibitors) for afterload reduction, and be sure to continue home infusions (i.e. epoprostenol) for patients who are on them.  Dobutamine or milrinone can be used for inotropic support.
• Avoid endotracheal intubation, if possible, due to risk of peri-intubation cardiac arrest. High-flow nasal cannula or noninvasive ventilation should be considered first. In patients requiring intubation, use vasopressor support (and pulmonary vasodilators if able) prior to intubation and minimize plateau pressures and PEEP to maintain preload.
• Treat arrhythmias with rapid electrical cardioversion rather than beta blockers or calcium channel blockers, which can worsen cardiac output.

Source
Right heart failure: A narrative review for emergency clinicians. Am J Emerg Med. 2022 Aug;58:106-113. doi: 10.1016/j.ajem.2022.05.030. Epub 2022 May 25.