What is the most common source of lower or upper extremity peripheral arterial embolus?

The most common source of lower or upper extremity peripheral arterial embolus is indeed the heart. This is primarily due to several cardiovascular conditions that lead to the formation of emboli within the heart chambers, especially in the left atrium. Conditions such as atrial fibrillation, myocardial infarction, and heart valve disease can result in the development of thrombi, or clots, that can dislodge and travel through the bloodstream.

When these clots are released, they can lodge in various peripheral arteries, causing acute ischemia, which can manifest as pain or loss of function in the affected limb. Understanding this pathophysiology is crucial for diagnosing and managing patients with peripheral arterial occlusive disease, as prompt identification and intervention can significantly affect outcomes.

Other options, while relevant in discussions of embolic sources, do not represent the most prevalent cause. Aneurysmal mural thrombus refers specifically to clots that form on the walls of aneurysms which can also embolize but are less common than cardiac sources. Deep vein thrombosis is primarily a problem that leads to pulmonary embolism rather than peripheral arterial embolism. Carotid artery disease can lead to emboli but is not as significant a source compared to cardiac conditions.