Analysis of skew of visible laser reflections in a living sheep heart

Limited methods exist to confirm the position of cardiovascular devices in the heart. In our earlier work, an optical fiber was enclosed in a central catheter and guided to known positions in the superior vena cava and right atrium in the heart of a living sheep. The tissues were illuminated with two wavelengths of visible light and the reflections were analyzed using frequency domain techniques. In this follow-up work, the data were reanalyzed using statistical estimates of skew and kurtosis as a function of anatomic position. Skew values from a 520 nm laser were able to determine catheter tip position near the cavoatrial junction as validated against known positions previously determined with electrocardiogram and contrast-enhanced video fluoroscopy. This method successfully confirmed the location of the catheter tip at the cavoatrial junction in 84% of 840 trials. Further research with refined apparatus and algorithms on additional animal subjects is strongly suggested.