Methodology for Cross-Talk Elimination in Simultaneous Voltage and Calcium Optical Mapping Measurements With Semasbestic Wavelengths

Most cardiac arrhythmias at the whole heart level result from alteration of cell membrane ionic channels and intracellular calcium concentration ([Ca2+](i)) cycling with emerging spatiotemporal behavior through tissue-level coupling. For example, dynamically induced spatial dispersion of action potential duration, QT prolongation, and alternans are clinical markers for arrhythmia susceptibility in regular and heart-failure patients that originate due to changes of the transmembrane voltage (V-m) and [Ca2+](i). We present an optical-mapping methodology that permits simultaneous measurements of the V-m - [Ca2+](i) signals using a single-camera without cross-talk, allowing quantitative characterization of favorable/adverse cell and tissue dynamical effects occurring from remodeling and/or drugs in heart failure. We demonstrate theoretically and experimentally in six different species the existence of a family of excitation wavelengths, we termed semasbestic, that give no change in signal for one dye, and thus can be used to record signals from another dye, guaranteeing zero cross-talk.

Automated summary

Most cardiac arrhythmias result from changes in cell membrane channels and intracellular calcium concentration. This study presents an optical-mapping methodology that allows simultaneous measurements of transmembrane voltage and calcium signals without cross-talk. This has important implications for understanding the effects of heart failure and drug treatments on cellular and tissue dynamics.