NONINVASIVE ASSESSMENT OF VENTRICULAR DAMAGE IN RATS WITH MYOCARDIAL-INFARCTION

Objective: The aim was to evaluate whether two dimensional echocardiog raphic/Doppler (echo/Doppler) techniques could be used to detect left ventricular damage rapidly, accurately, and non-invasively in rats wit h a myocardial infarction. Methods: Female Wistar rats were initially subjected to either a sham operation or surgery to induce a myocardial infarct by ligating the left main coronary artery. Following a minimu m of six weeks to recover from the surgery, all rats were reanaestheti sed and cardiac and stroke indexes were determined at similar heart ra tes, using echo/Doppler techniques. Postmortem histological assessment of myocardial infarct size was compared with the non-invasive detecti on of left ventricular wall motion abnormalities, left ventricular dil atation, and the presence of a left ventricular aneurysm found in the living animal. Results: Rats with myocardial infarction (n=8) showed a 33(SEM 4)% reduction (p<0.01) in cardiac index (due to a 33% reductio n in stroke index) when compared to their non-infarcted counterparts ( n=5). In addition, a significant correlation (r=0.84; n=25; p<0.01) wa s found between the assessment of left ventricular damage via non-inva sive echo/Doppler measurements and the histological determination of i nfarct size. Conclusions: These results support the conclusion that tw o dimensional echo/Doppler techniques can be used to estimate rapidly and non-invasively the degree of left ventricular damage produced in l iving rats with myocardial infarction when compared to non-infarcted c ontrols.