Noncardiogenic mechanisms of right heart dysfunction

Alterations in right ventricular (RV) performance are critical to the cardiac dysfunction witnessed in adult respiratory distress syndrome (ARDS), septic shock (SS), and as a consequence of positive end-expiratory pressure (PEEP) administration during mechanical ventilation. The authors review evidence for right heart dysfunction in these circumstances. In ARDS, an increase in RV afterload with the onset of pulmonary artery hypertension is the predominant factor promoting RV dysfunction. In SS, most investigators agree that a primary decrease in myocardial contractility is the major factor limiting RV performance. The application of PEEP during mechanical ventilation can potentiate alterations in RV preload, afterload, and/or contractility, all of which promote RV dysfunction and compromise left ventricular filling. As RV dysfunction may seriously affect global myocardial performance in all of these settings, the clinician must identify that RV function is impaired, discern the contributing mechanism, and select an appropriate therapeutic regimen targeted at addressing this predominant mechanism. Assessment and management strategies are described.