From the Guidelines
The right ventricular (RV) heart failure is not entirely preload dependent.
Key Points
- The traditional view that the RV is preload dependent can lead to inappropriate volume loading, worsening RV dilation and tricuspid regurgitation 1.
- The RV prefers euvolemia with a central venous pressure of 8 to 12 mm Hg, and diuresis can reduce ventricular dilation and improve biventricular coupling 1.
- RV distention can cause leftward interventricular septal shift, compromising left ventricular (LV) filling and reducing cardiac output (CO) 1.
- The use of calcitropic agents has been associated with a progressive decline in RV function, possibly due to systemic vasodilation and decreased right-sided perfusion pressures 1.
- In some cases, concomitant use of vasopressin or norepinephrine may be needed to maintain RV perfusion during inodilator therapy, particularly with milrinone 1.
From the Research
Right Ventricular Heart Failure Preload Dependence
- The right ventricle (RV) is highly sensitive to changes in loading conditions, including preload and afterload 2, 3.
- RV failure can occur due to increased afterload or decreased preload, and its adaptation to different loading conditions can result in distinct patterns of RV adaptation 2.
- The Frank-Starling mechanism is active in RV failure, indicating that the RV is preload-dependent 2.
- However, RV contractility and diastolic function can also be affected by afterload and intrinsic RV dysfunction, making RV failure a complex condition that is not solely dependent on preload 4, 5, 6.
- Studies have shown that RV function can be impaired in patients with heart failure with preserved ejection fraction (HFpEF), even in the absence of significant changes in preload, suggesting that RV failure can occur independently of preload 6.
Factors Affecting RV Preload Dependence
- Inspiratory load can significantly affect RV function, particularly in patients with respiratory failure, by altering RV preload and afterload 3.
- Venous return, which is a contributor to RV preload, can change in opposite directions depending on the type of ventilation (spontaneous or assisted) 3.
- Lung inflation and driving pressure can also impact RV afterload, leading to RV failure in severe cases 3.
- RV-pulmonary artery coupling and ventricular interdependence can also play a role in RV failure, making it a complex condition that is not solely dependent on preload 4.