Three-dimensional surface reconstruction and fluorescent visualization of cardiac activation

Abstract

Optical imaging of transmembrane potentials in cardiac tissue is a rapidly growing technique in cardiac electrophysiology. Traditional studies typically use a monocular imaging setup, thus limiting investigation to a restricted region of tissue. However, studies of large-scale wavefront dynamics, especially those during fibrillation and defibrillation, would benefit from visualization of the entire epicardial surface. To solve this problem, a panoramic cardiac visualization algorithm was developed which performs the two tasks of reconstruction of the surface geometry of the heart, and representation of the panoramic fluorescence information as a texture mapping onto the geometry that was previously created. This system permits measurement of epicardial electrodynamics over a geometrically realistic representation of the actual heart being studied. To verify the accuracy of the algorithm, the procedure was applied to synthetic images of a patterned ball; further verification was provided by application of the algorithm to a model heart placed in the experimental setup. Both sets of images produced mean registration image errors on the order of 2 pixels, corresponding to roughly 3 mm on the geometry. We demonstrate the algorithm by visualizing epicardial wavefronts on an isolated, perfused rabbit heart.

Sustained Reentry in the Left Ventricle of Fibrillating Pig Hearts

“…This issue can be resolved, at least for epicardial reentry, using a mapping technology that images the entire epicardium, eg, panoramic mapping. 16 Another possible ex- planation is that sustained reentry is dependent on the size of the heart. We found that the hearts with sustained reentry were significantly smaller than the hearts without.…”

Panoramic Optical Imaging of Cardiac Arrhythmias

“…These multiple points of view can be obtained with a single detector and mirror arrangement or with multiple detectors positioned around the heart. In the first systems implemented by Lin and Wikswo [7] and subsequently by Bray et al [3] a single optical detector was used in combination with two mirrors positioned at the back of the heart to show the reflected images of the posterior surface (Figure 10.1a). In this system, a CCD camera was used and a horizontal rectangular region of interest was implemented to collect all three views of the heart (reflected images simultaneously collected on either side of the direct image on the CCD chip).…”

“…To overcome these limitations, several groups have developed panoramic optical mapping systems [3][4][5]. The earliest implementations of panoramic imaging involved using multiple optical detectors to simultaneously image multiple views of the heart [6], or conversely, a single optical detector with a mirror arrangement to simultaneously image multiple views on the same detector [7].…”

“…Bray et al [3] were the first to implement 3D reconstruction of the heart surface geometry before texture-mapping the optical signals back onto the anatomically correct 3D heart surface. This approach allowed, for the first time, complete visualization of electrophysiological activity on the entire epicardial surface of the intact Langendorff-perfused rabbit heart.…”

Multiparametric Optical Mapping of the Langendorff-perfused Rabbit Heart

“…The panoramic mapping system is used to map the entire epicardium of the rabbit heart [4][5][6][7] . This system provides a global view of the evolution of reentrant circuits during arrhythmogenesis and defibrillation, and has been used to study the mechanisms of arrhythmias and antiarrhythmia therapy 8,9 .…”