To assess the phase-character of the relationship between myocardial infarct size (IS) and left yentricular function (LVF)

myocardial infarction (MI) of left ventricle was produced in rats by coronary ligation. The indices of LVF and IS were measured on 3 (n=24)

9(n=22)

21 (n=25)

and 35-day groups (n=23) respectively after the operation

and their correlations were compaired among the four groups. Significant correlations between IS (ranging from 10 to 65% of the left ventricle) and functional indices were found in all groups

denoting IS to be the most important determinant on LVF in the different phases of MI. In the acute phase (3-day group)

however

this relationship was not as good as that in the other phases

which might be explained by the diverse revolving-types of cardiac function in ventricles with a spectrum of IS after MI

or by the time-dependent effects of other influencial factors on LVF