Paradoxical embolism
Encyclopedia
A paradoxical embolism is a kind of stroke
or other form of arterial thrombosis caused by embolism
of a thrombus
(blood clot) of venous origin through a lateral opening in the heart, such as a patent foramen ovale.
The opening is typically an atrial septal defect
, but can also be a ventricular septal defect
.
Paradoxical embolisms represent two percent of arterial emboli.
. On the other hand, when there is a hole in the wall between the two upper chambers of the heart (an atrial septal defect), a clot can cross from the right to the left side of the heart, then pass into the arteries as a paradoxical embolism. Once in the arterial circulation, a clot can travel to the brain, block a vessel there, and cause a stroke (cerebrovascular accident). Also called crossed embolism.
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
or other form of arterial thrombosis caused by embolism
Embolism
In medicine, an embolism is the event of lodging of an embolus into a narrow capillary vessel of an arterial bed which causes a blockage in a distant part of the body.Embolization is...
of a thrombus
Thrombus
A thrombus , or blood clot, is the final product of the blood coagulation step in hemostasis. It is achieved via the aggregation of platelets that form a platelet plug, and the activation of the humoral coagulation system...
(blood clot) of venous origin through a lateral opening in the heart, such as a patent foramen ovale.
The opening is typically an atrial septal defect
Atrial septal defect
Atrial septal defect is a form of congenital heart defect that enables blood flow between the left and right atria via the interatrial septum. The interatrial septum is the tissue that divides the right and left atria...
, but can also be a ventricular septal defect
Ventricular septal defect
A ventricular septal defect is a defect in the ventricular septum, the wall dividing the left and right ventricles of the heart.The ventricular septum consists of an inferior muscular and superior membranous portion and is extensively innervated with conducting cardiomyocytes.The membranous...
.
Paradoxical embolisms represent two percent of arterial emboli.
Pathophysiology
Passage of a clot (thrombus) from a vein to an artery. When clots in veins break off (embolize) , they travel first to the right side of the heart and, normally, then to the lungs where they lodge, causing pulmonary embolismPulmonary embolism
Pulmonary embolism is a blockage of the main artery of the lung or one of its branches by a substance that has travelled from elsewhere in the body through the bloodstream . Usually this is due to embolism of a thrombus from the deep veins in the legs, a process termed venous thromboembolism...
. On the other hand, when there is a hole in the wall between the two upper chambers of the heart (an atrial septal defect), a clot can cross from the right to the left side of the heart, then pass into the arteries as a paradoxical embolism. Once in the arterial circulation, a clot can travel to the brain, block a vessel there, and cause a stroke (cerebrovascular accident). Also called crossed embolism.