Article Impact Level: HIGH Data Quality: STRONG Summary of Journal of Biomedical Optics https://doi.org/10.1117/1.JBO.31.7.076004 Dr. Grant Kowalik et al.
Points
- George Washington University researchers engineered a six-camera panoramic platform combining hyperspectral tissue characterization with high-speed optical action potential mapping across whole living hearts.
- Hyperspectral sensors detected collagen fluorescence between 400 and 520 nm, enabling a k-means clustering algorithm to classify healthy, border zone, and infarcted myocardium.
- Programmed electrical stimulation at S1-S2 intervals of 80 to 65 milliseconds induced premature ventricular contractions and reentrant arrhythmias in three out of four infarcted hearts.
- Optical mapping confirmed that action potential duration was longest in infarcted scar tissue, intermediate within the border zone, and shortest in healthy cardiac muscle.
- Structural conduction blocks and wave slowing within collagen-rich scar tissue created the electrophysiological substrate necessary to initiate and sustain post-infarction ventricular reentrant arrhythmias.
Summary
The feasibility of a novel six-camera panoramic imaging platform combining high-resolution hyperspectral imaging with optical action potential mapping to correlate epicardial tissue composition with electrophysiological dysfunction. While traditional optical mapping tracks excitation wave propagation, it fails to differentiate underlying tissue histology. Developed by researchers at George Washington University, this system was designed to map tissue structure and electrophysiological function simultaneously across the surface of whole hearts, specifically targeting the arrhythmogenic substrates generated by post-infarction scarring.
The platform was tested on ex vivo perfused rat hearts four weeks after experimental myocardial infarction. Four high-speed cameras captured fluorescent voltage signals, while additional sensors collected 3D epicardial geometry and spectral emissions. Hyperspectral analysis identified collagen fluorescence within the 400 to 520 nm spectral band, and a k-means clustering algorithm using the integral of spectral intensity from 400 to 435 nm successfully categorized regions into healthy muscle, border zone, or infarcted tissue. Under S1-S2 pacing protocols (S1 = 150 msec; S1-S2 intervals between 80 and 65 msec), premature ventricular contractions (PVCs) and reentrant activity were induced in 3 of 4 hearts, with ectopic beats originating at the infarct border and conducting around the scar.
Quantitative electrophysiological mapping revealed that action potential duration (APD) varied directly by tissue classification: APD was longest in infarcted tissue, intermediate in border zones, and shortest in healthy myocardium. Excitation waves slowed or blocked completely within scarred zones, creating conditions for reentrant circuits. The authors conclude that integrating panoramic hyperspectral imaging with voltage mapping provides a robust method for quantitative structure-function analyses, establishing a powerful diagnostic approach for investigating post-infarction remodeling, fibrosis, and arrhythmia triggers.
References
Kowalik, G., Loew, M., Mendelowitz, D., Entcheva, E., & Kay, M. W. (2026). Panoramic hyperspectral optical mapping of cardiac membrane potential and tissue type. Journal of Biomedical Optics, 31(07). https://doi.org/10.1117/1.JBO.31.7.076004
