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

• Authors: Ilija Uzelac, Georgia Institute of Technology; Christopher J Crowley, Georgia Institute of Technology; Shahriar Iravanian, Emory University; Tae Yun Kim, Emory University; Hee Cho, Emory University; Flavio H Fenton, Georgia Institute of Technology
• Journal Title: FRONTIERS IN PHYSIOLOGY
• Volume: Volume 13
• Publisher: FRONTIERS MEDIA SA | 2022-02-11, Pages 812968-812968
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.3389/fphys.2022.812968
• Subjects: Engineering, Biomedical
• Keywords: Science & Technology; Life Sciences & Biomedicine; Physiology; optical mapping; semasbestic wavelength; isosbestic point; fluorescent dyes; transmembrane voltage; intracellular free calcium concentration; alternans; T-WAVE ALTERNANS; ACTION-POTENTIALS; HEART-FAILURE; MECHANISM; DEATH; FIBRILLATION; INSTABILITY; TRANSIENTS; EXCITATION; PHYSIOLOGY

Abstract

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 (Vm) and [Ca2+]i. We present an optical-mapping methodology that permits simultaneous measurements of the Vm - [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.