What is the mechanism of systemic circulation congestion in right heart failure?

When right heart failure occurs, the pumping capacity of the right ventricle is significantly reduced, leading to blood congestion within the right ventricle and ineffective ejection. This congestion further causes an increase in right ventricular end-diastolic pressure, forcing blood from the right ventricle into the right atrium due to elevated pressure, resulting in right atrial enlargement and increased pressure.

As right atrial pressure rises, it begins to impede venous return from the superior and inferior vena cava into the right atrium. These veins are responsible for transporting systemic venous blood back to the right atrium, but increased right atrial pressure obstructs this return, reducing systemic venous return.

This change directly causes systemic venous congestion, manifesting as blood stasis in the venous system, such as jugular venous distension and lower limb edema. Additionally, systemic venous congestion may lead to various symptoms, including gastrointestinal congestion causing abdominal distension, nausea, and vomiting, as well as signs such as hepatic congestion and pleural or peritoneal effusion.

In terms of treatment, it is essential to address the underlying cause while using diuretics to reduce systemic venous congestion and improve symptoms.