Echocardiography (Echo) in small rodents is a well established technique for non-invasive examinations of heart function and geometry. The estimation of ventricular volume and ejection fraction (EF) from parasternal planes or even M-Mode assume constant geometric proportions over time. To use the more reliable Simpson's method for volume measurements from the apical planes the essential demarcation of the ventricular inner border can be improved in rat hearts by injection of ultrasound contrast medium. MI was induced in rats by ligation of the LAD. Echo was performed one day before MI and two-weekly for 16 weeks. After taking native standard records (GE, Vivid7, 11.5Mhz) the tail vein was punctured and 100–200 ml Optision® contrast medium were injected. Contrast enhanced two- and four-camber views were taken and systolic and diastolic volumes were calculated. 16 weeks after MI heart function was examined invasively with Millar tip catheters. The biplane measured EF decreased from 60±3% to 23±2% (mean±SD) and showed a good correlation (R² 0.86) to the fractional area change from parasternal short axis (47±6% to 18±3%). The biplane measured LVEDV increased from 320±55ìl to 1044±36ìl, but correlated just loosely (R² 0.71) with short axis ED area (0,39±0,06cm² to 1,11±0,13cm²). Contrast enhanced Echo in rats is a practical and more exact method to measure heart dimensions compared to native measurements in parasternal planes.