Unlike many other engineering designs, the heart, a pressure vessel, shows variations within its chambers and surface in terms of mechanical function. This necessitates a whole field technique with high spatial resolution. Computer aided speckle interferometry (CASI), a nondestructive examination technique, is herein developed for this purpose. A speckle pattern was created on the surface of isolated rabbit hearts. Images of the beating hearts werc acquired with a charge-couple device (CCD) camera for one second at a rate of 50 frames per second. CASI was used to determine the 2-D displacement vectors over regions of approximately 4 × 6 mm. Regional area stroke work (the integral of the left ventricular pressure with respect to area), the first invariant of the 2-D strain tensor, and the principle strains were used to determine the regional function. After occluding the blood supply to a region of the heart, significant changes were detected in all the previously mentioned parameters. Commonly used techniques cannot determine 2-D strain and lack the high spatial resolution of CASI. Determination of the 2-D strain can provide useful data on the functionality of the heart.

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