Determination of Regional Stroke Work With High Spatial Resolution in the Isolated Beating Rabbit Heart

The determination of regional function in the beating heart necessitates a technique to measure local deformation with high spatial resolution. We have previously reported the ability of computer aided speckle interferometry (CASI) to accurately determine deformation in the non-beating heart. Herein we use this technique to ascertain regional deformation allowing for the determination of regional area-left ventricular pressure loops, also known as regional stroke work. An isolated rabbit heart was placed in a modified Langendorff apparatus that allowed the left ventricle to develop pressure and eject volume into the aorta. CASI was used to determine the simultaneous deformation of over 900 points located in a region approximately 4 × 6 mm on the anterior surface of the left ventricle. The heart was then subjected to regional ischemia and data were again acquired. Over the whole region, the average regional stroke work decreased at both 2 and 5 minutes of regional ischemia, which partially recovered upon reperfusion. In addition, this region was subdivided into 24 areas, and regional stroke work was determined in each area and similar results to that obtained over the whole region were found.