What is the physiological basis of clinical features of right ventricular (RV) failure?

From the Guidelines

Right ventricular failure occurs when the right ventricle cannot effectively pump blood to the lungs, leading to characteristic clinical features that stem from specific physiological mechanisms, primarily increased right ventricular pressure and volume overload, as noted in the 2018 American Heart Association scientific statement 1. The primary physiological basis involves increased right ventricular pressure and volume overload, which causes backward transmission of pressure into the systemic venous circulation. This backward pressure leads to:

• Peripheral edema, particularly in dependent areas like the ankles and sacrum, as fluid leaks from capillaries into interstitial spaces due to increased hydrostatic pressure
• Jugular venous distention occurs as elevated right atrial pressure transmits directly to the jugular veins
• Hepatomegaly and ascites develop when increased pressure transmits through the inferior vena cava to the hepatic veins, causing liver congestion, impaired function, and fluid accumulation in the peritoneal cavity Patients often experience fatigue and exercise intolerance because reduced right ventricular output leads to decreased left ventricular filling (ventricular interdependence), resulting in diminished cardiac output and oxygen delivery to tissues, as discussed in the assessment of right ventricular function in the research setting by the American Thoracic Society 1. Dyspnea occurs due to pulmonary congestion in biventricular failure or from decreased oxygen delivery with increased respiratory drive. Right ventricular dilation can cause tricuspid regurgitation as the valve annulus stretches, further exacerbating venous congestion. In advanced cases, cardiac cachexia may develop from chronic inflammatory activation, malabsorption from intestinal edema, and increased metabolic demands, while pleural effusions form as elevated systemic venous pressure affects lymphatic drainage from the pleural space, highlighting the complex pathophysiology of right ventricular failure 1. The evaluation and management of right-sided heart failure, as outlined in the 2018 American Heart Association scientific statement 1, emphasize the importance of understanding the physiological basis of clinical features of right ventricular failure to guide assessment and therapeutic decision making. Key aspects of right ventricular failure include:
• Increased right ventricular pressure and volume overload
• Backward transmission of pressure into the systemic venous circulation
• Peripheral edema, jugular venous distention, hepatomegaly, and ascites
• Fatigue, exercise intolerance, and dyspnea due to decreased cardiac output and oxygen delivery
• Tricuspid regurgitation and cardiac cachexia in advanced cases, as supported by the evidence from the American Thoracic Society research statement 1.

From the Research

Physiological Basis of Right Ventricular Failure

The physiological basis of clinical features of right ventricular (RV) failure is complex and involves multiple factors. Key aspects include:

• Inability of the right ventricle to provide adequate blood flow through the pulmonary circulation at a normal central venous pressure 2
• Right ventricular pressure overload and contractile abnormalities of the right ventricular free wall 2
• Increased afterload, which can lead to right ventricular failure, especially in conditions such as pulmonary hypertension 3, 4
• Importance of right ventricular function in maintaining global cardiac performance, with physiological determinants including afterload and contractility characteristics 5

Clinical Features of Right Ventricular Failure

Clinical features of right ventricular failure include:

• Systemic venous hypertension, peripheral oedema, and impaired ability of the right heart to provide tissue perfusion 6
• Swelling of the neck veins with an elevation of jugular venous pressure and ankle oedema 6
• Fluid accumulation, including extensive oedema of the legs, congestive hepatomegaly, and eventually ascites 6
• Diagnosis requires the presence of signs of elevated right atrial and venous pressures, including dilation of neck veins, with at least one of the following criteria: compromised RV function, pulmonary hypertension, or peripheral oedema and congestive hepatomegaly 6

Pathogenesis and Management

The pathogenesis of right ventricular failure involves the incompetence of the right heart to maintain systemic venous pressure sufficiently low to guarantee optimal venous return and preserve renal function 6. Management strategies include:

• Optimization of fluid balance, cardiac output, and perfusion pressure 3
• Reduction of RV afterload with PAH-targeted therapies 3
• Consideration of extracorporeal life support, lung transplantation, or heart-lung transplantation in cases of refractory RVF 3
• Pharmacological interventions, such as vasodilators and inotropes, and/or mechanical assist devices 5