Acute
ischemias of the legs of cardiac origin are almost always due to leg
embolus caused by fragmentation of an endoauricular or left venticular
thrombosis. The two main causes are easily recognized: mitral narrowing and ventricular
aneurysm are seldom accompanied by seeding, because a prophylactic treatment with anti-
vitamin K is started as soon as the diagnosis is made. Use of prosthetic valves, despite constant improvement in their manufacture and systematic administration of
anticoagulant drugs, are always complicated by
embolisms (4 to 7% of cases at present). On the other hand, two causes of leg
embolisms should be carefully sought since they give rise to revealing seedings. Non-obstructive
cardiomyopathy gives a picture of primitive cardiac insufficiency developing progressively. Paroxysmal supraventricular rhythm disorders may be completely overlooked, and only an electrocardiogram continued during 24 hours allows their detection.
Embolisms which do not involve the legs, are secondary. Seeding of a chalky fragment from a stenotic aortic valve is very rare. On the other hand,
embolisms of anauricular fragment of
myxoma and especially membranous
embolisms during infectious
endocarditis, are not so rare.