Which cardiac chamber is most likely to be involved with metastatic tumors?

The right atrium is the cardiac chamber most commonly involved with metastatic tumors due to its anatomical position and the nature of blood flow in the circulatory system. Metastatic tumors often spread through the bloodstream, and venous blood, which can carry cancer cells, returns to the heart via the superior and inferior vena cavae directly into the right atrium.

This chamber serves as a common site for the accumulation of cancer cells because it receives blood from the systemic circulation, where most cancers disseminate initially. Cancer types such as renal cell carcinoma, melanoma, and certain lymphomas have a propensity to metastasize to the heart, frequently affecting the right atrium.

In terms of direct involvement, the right atrium's structure and location make it a frequent target for metastasis, compared to other chambers. Other chambers like the left atrium, left ventricle, and right ventricle may also be affected, but they are less commonly involved in the metastatic process due to factors such as their separate circulation (the left side of the heart dealing with oxygenated blood) and the fact that they are not directly receiving venous return from the systemic circulation.

Thus, the significant tendency for cancer cells to reach the right atrium as they