From which side of the heart do clots that become pulmonary emboli originate?

Clots that become pulmonary emboli typically originate from the venous system, which means they arise from the right side of the heart, particularly the right atrium. These clots are often formed in the deep veins of the legs and can dislodge, traveling through the right side of the heart before reaching the pulmonary arteries. Once in the pulmonary arteries, they can obstruct blood flow to the lungs, resulting in a pulmonary embolism.

While clots from the left atrium or ventricle can cause systemic emboli, they do not lead to pulmonary embolism directly. Therefore, the right atrium is the correct origin point for clots that lead to this specific condition. Understanding the blood flow dynamics and the pathways through which clots can travel is crucial in critical care and helps in identifying risk factors and preventive measures for patients at risk of pulmonary embolism.