LIMITATION OF INFARCT SIZE

Abstract

There is lack of standardization. Secondly the natir1 history of S-T reduction in the 1 St few hours is variable and many other factors may modify the ST segment e.g. pericarditis. Thus new methods of assessing the infarct size in man are being sought. More recently positron emission trans axial tomography and two dimension echocardiography with computer aided semiautomated contouring system assement of the infarct size has been applied to the study of myocardial-infarct size in man. The latter method has shown that extension of myocardial infarction may not be so common as believed earlier however expansion of myocardial infarction that is thinning and strctching with resultant widening of the previous infarction zone altering the geometry and there by function of Left Ventricule is quite commonly seen by about the 6th day. The exact cause of this is not known nor is the effect of these interventions known on “expansion” rather than extension. Thus As a usual new question has arisen, further studies of these two methods is awaited. Meanwhile arnon2 claims and counterclaims the following points-appear reasonably clear;

1. Nitroglycerin improves Left Ventricular function in Acute myocardial infarction associated with Left Ventricular failure if given very early in the course of the disease without increase in M.V.02 whether it limits infarction or not. Its effect on Acute Myocardial Infarction without Left ventricular failure is not so clear.
2. All vasodilators are not. the same and some of them may have deleterious effects.
3. Digoxin improves MV 02 in Acute myocardial infarction with Left ventricular failure while its effect is otherwise if there is no Left ventricular failure.
The use of these modelities is still experimental and their use in clinical setting should be extremely careful and controlled.