Left ventricular dysfunction in XXXX : fundamental importance of the fibrous matrix.

@entity82 @entity1369 @entity712 @entity39 @entity1184 @entity384 @entity1188 @entity741
The contractile function of the myocardium is coordinated by a fibrous matrix of exquisite organization and complexity. In the normal heart, and apparently in physiological @entity1184 , this matrix is submicroscopic. In pathological states changes are frequent, and usually progressive. Thickening of the many elements of the fine structure is due to an increased synthesis of Type I collagen, This change, which affects the myocardium in a global manner, can be observed by light microscopy using special techniques. Perivascular @entity82 , with an increase in vascular smooth muscle, is accompanied by development of fibrous septa, with a decrease in diastolic compliance. These structural changes are believed to be due to increased activation of the renin-angiotensin- @entity1369 system, and to be independent of the processes of myocyte @entity1184 . Reparative or replacement @entity82 is a separate process by means of which small and large areas of @entity39 heal, with the development of coarse collagen structures, which lack a specific organizational pattern. Regarding @entity741 , an increase in tissue collagenase is found in experimental myocardial "stunning" and in the very early phase of acute @entity1188 . Absence of elements of the fibrous matrix allow for myocyte slippage, and--if the affected area is large--cardiac dilatation. If, subsequently, the @entity39 becomes transmural, there is further disturbance of collagen due to both mechanical strain and continued autolysis, During healing collagen synthesis increases greatly to allow for reparative scarring in the available tissue matrix. In cases of @entity1188 with moderate or severe @entity384 , pathological @entity1184 of the spared myocardium is progressive, accounting for late @entity712 and poor survival.(ABSTRACT TRUNCATED AT 250 WORDS)
