NONINVASIVE ASSESSMENT OF VENTRICULAR DAMAGE IN RATS WITH MYOCARDIAL-INFARCTION

Objective: The aim was to evaluate whether two dimensional echocardiographic/Doppler (echo/Doppler) techniques could be used to detect left ventricular damage rapidly, accurately, and non-invasively in rats with 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 minimum of six weeks to recover from the surgery, all rats were reanaesthetised and cardiac and stroke indexes were determined at similar heart rates, using echo/Doppler techniques. Postmortem histological assessment of myocardial infarct size was compared with the non-invasive detection of left ventricular wall motion abnormalities, left ventricular dilatation, 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% reduction 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) was found between the assessment of left ventricular damage via non-invasive echo/Doppler measurements and the histological determination of infarct size. Conclusions: These results support the conclusion that two dimensional echo/Doppler techniques can be used to estimate rapidly and non-invasively the degree of left ventricular damage produced in living rats with myocardial infarction when compared to non-infarcted controls.