Non-invasive assessment of ventricular damage in rats with myocardial infarction

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.

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 re-anaesthetised 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.

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.

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.