Thick blood caused by polycythemia can place significant strain on which part of the heart?

Thick blood resulting from polycythemia primarily increases the workload on the right side of the heart. This condition can lead to higher pulmonary blood pressure due to the increased viscosity of the blood, which makes it more challenging for the right ventricle to pump blood effectively into the lungs. Over time, the additional strain can lead to right-sided heart failure or cor pulmonale, as the structure must work harder to overcome this increased resistance in the pulmonary circulation.

Additionally, while conditions affecting blood viscosity can impact the left side of the heart in certain contexts, the immediate effect of polycythemia predominantly stresses the right side due to its role in pulmonary circulation. The aorta and vena cava are not primarily affected by the increased strain from thick blood in terms of direct cardiac workload, as they function as conduits for blood flow rather than pumping mechanisms.