When right-sided congestive heart failure occurs, what happens?

When right-sided congestive heart failure occurs, it primarily leads to excess blood and fluid backup in the systemic circulation. This is a result of the right side of the heart being unable to effectively pump blood to the lungs for oxygenation. As a consequence, blood backs up in the veins that return blood to the heart, which can cause swelling in the legs, abdomen, and various organs due to increased venous pressure and fluid retention.

This situation distinguishes right-sided heart failure from left-sided heart failure, where the backup primarily affects the lungs, leading to pulmonary congestion. The systemic effects seen in right-sided heart failure often manifest as symptoms like peripheral edema and hepatomegaly, further emphasizing the role of fluid overload in the body's circulation.

In contrast, the other options presented do not accurately describe the effects of right-sided congestive heart failure. Summation of blood flow in the heart does not occur; rather, the flow is compromised. Reduced blood pressure throughout the body is not a defining outcome since the overall systemic pressure can vary depending on various physiological responses. Lastly, increased oxygen supply to the lungs does not happen because the right side of the heart is failing to perform its role effectively, resulting in inadequate oxygenation rather than an increase in supply.