scholarly journals A Complete and Low-Cost Cardiac Optical Mapping System in Translational Animal Models

2021 ◽  
Vol 12 ◽  
Author(s):  
Manuel Marina-Breysse ◽  
Alba García-Escolano ◽  
Joaquín Vila-García ◽  
Gabriel Reale-Nosei ◽  
José M. Alfonso-Almazán ◽  
...  
Keyword(s):  
Action Potentials ◽  
Cardiac Electrophysiology ◽  
High Speed ◽  
Optical Mapping ◽  
Low Cost ◽  
Cytosolic Calcium ◽  
Calcium Transients ◽  
Spatiotemporal Resolution ◽  
Mapping System ◽  
Computer Scientists

Clinicians, biologists, physicists, engineers, and computer scientists are coming together to better understand heart disease, which is currently the leading cause of death globally. Optical mapping, a high-speed fluorescence imaging technique that visualizes and measures key cardiac parameters such as action potentials, cytosolic calcium transients, and fibrillation dynamics, is a core research tool that has arisen from such interdisciplinary collaborations. In an effort to broaden its use, especially among clinical scientists and students, we developed a complete and low-cost optical mapping system, including a constant-flow Langendorff perfusion system, which minimizes the economic threshold to widespread use of this powerful tool in cardiac electrophysiology research. The system described here provides high spatiotemporal resolution data about action potentials, intracellular calcium transients and fibrillation wave dynamics in isolated Langendorff-perfused hearts (pigs and rabbits), relevant for translational research. All system components and software elements are fully disclosed with the aim of increasing the use of this affordable and highly versatile tool among clinicians, basic scientists and students wishing to tackle their own research questions with their own customizable systems.

Mapping action potentials and calcium transients simultaneously from the intact heart

2001 ◽  
Vol 280 (5) ◽  
pp. H2053-H2060 ◽  
Author(s):  
Kenneth R. Laurita ◽  
Ashish Singal
Keyword(s):  
Action Potentials ◽  
Cardiac Electrophysiology ◽  
Optical Mapping ◽  
Fluorescence Emission ◽  
Calcium Transients ◽  
Calcium Handling ◽  
Guinea Pig Heart ◽  
Spectral Overlap ◽  
Intact Heart

Intracellular calcium handling plays an important role in cardiac electrophysiology. Using two fluorescent indicators, we developed an optical mapping system that is capable of measuring calcium transients and action potentials at 256 recording sites simultaneously from the intact guinea pig heart. On the basis of in vitro measurements of dye excitation and emission spectra, excitation and emission filters at 515 ± 5 and >695 nm, respectively, were used to measure action potentials with di-4-ANEPPS, and excitation and emission filters at 365 ± 25 and 485 ± 5 nm, respectively, were used to measure calcium transients with indo 1. The percent error due to spectral overlap was small when action potentials were measured (1.7 ± 1.0%, n = 3) and negligible when calcium transients were measured (0%, n = 3). Recordings of calcium transients, action potentials, and isochrone maps of depolarization time and the time of calcium transient onset indicated negligible error due to fluorescence emission overlap. These data demonstrate that the error due to spectral overlap of indo 1 and di-4-ANEPPS is sufficiently small, such that optical mapping techniques can be used to measure calcium transients and action potentials simultaneously in the intact heart.

scholarly journals In vivo ratiometric optical mapping enables high-resolution cardiac electrophysiology in pig models

2019 ◽  
Vol 115 (11) ◽  
pp. 1659-1671 ◽  
Author(s):  
Peter Lee ◽  
Jorge G Quintanilla ◽  
José M Alfonso-Almazán ◽  
Carlos Galán-Arriola ◽  
Ping Yan ◽  
...  
Keyword(s):  
High Resolution ◽  
Cardiac Electrophysiology ◽  
High Speed ◽  
Near Infrared ◽  
Optical Mapping ◽  
Ex Vivo ◽  
Average Rate ◽  
Camera System ◽  
Epicardial Surface

Abstract Aims Cardiac optical mapping is the gold standard for measuring complex electrophysiology in ex vivo heart preparations. However, new methods for optical mapping in vivo have been elusive. We aimed at developing and validating an experimental method for performing in vivo cardiac optical mapping in pig models. Methods and results First, we characterized ex vivo the excitation-ratiometric properties during pacing and ventricular fibrillation (VF) of two near-infrared voltage-sensitive dyes (di-4-ANBDQBS/di-4-ANEQ(F)PTEA) optimized for imaging blood-perfused tissue (n = 7). Then, optical-fibre recordings in Langendorff-perfused hearts demonstrated that ratiometry permits the recording of optical action potentials (APs) with minimal motion artefacts during contraction (n = 7). Ratiometric optical mapping ex vivo also showed that optical AP duration (APD) and conduction velocity (CV) measurements can be accurately obtained to test drug effects. Secondly, we developed a percutaneous dye-loading protocol in vivo to perform high-resolution ratiometric optical mapping of VF dynamics (motion minimal) using a high-speed camera system positioned above the epicardial surface of the exposed heart (n = 11). During pacing (motion substantial) we recorded ratiometric optical signals and activation via a 2D fibre array in contact with the epicardial surface (n = 7). Optical APs in vivo under general anaesthesia showed significantly faster CV [120 (63–138) cm/s vs. 51 (41–64) cm/s; P = 0.032] and a statistical trend to longer APD90 [242 (217–254) ms vs. 192 (182–233) ms; P = 0.095] compared with ex vivo measurements in the contracting heart. The average rate of signal-to-noise ratio (SNR) decay of di-4-ANEQ(F)PTEA in vivo was 0.0671 ± 0.0090 min−1. However, reloading with di-4-ANEQ(F)PTEA fully recovered the initial SNR. Finally, toxicity studies (n = 12) showed that coronary dye injection did not generate systemic nor cardiac damage, although di-4-ANBDQBS injection induced transient hypotension, which was not observed with di-4-ANEQ(F)PTEA. Conclusions In vivo optical mapping using voltage ratiometry of near-infrared dyes enables high-resolution cardiac electrophysiology in translational pig models.

scholarly journals Basic Concepts of Optical Mapping Techniques in Cardiac Electrophysiology

2009 ◽  
Vol 11 (2) ◽  
pp. 195-207 ◽  
Author(s):  
Mina Attin ◽  
William T. Clusin
Keyword(s):  
Membrane Potential ◽  
Cardiac Electrophysiology ◽  
Optical Mapping ◽  
Simultaneous Recording ◽  
Calcium Transients ◽  
Mapping Technique ◽  
Basic Concepts ◽  
Temporal And Spatial ◽  
Mapping Techniques ◽  
Whole Heart

Optical mapping is a tool used in cardiac electrophysiology to study the heart’s normal rhythm and arrhythmias. The optical mapping technique provides a unique opportunity to obtain membrane potential recordings with a higher temporal and spatial resolution than electrical mapping. Additionally, it allows simultaneous recording of membrane potential and calcium transients in the whole heart. This article presents the basic concepts of optical mapping techniques as an introduction for students and investigators in experimental laboratories unfamiliar with it.

scholarly journals COSMAS: a lightweight toolbox for cardiac optical mapping analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jakub Tomek ◽  
Zhinuo Jenny Wang ◽  
Rebecca-Ann Beatrice Burton ◽  
Neil Herring ◽  
Gil Bub
Keyword(s):  
Action Potentials ◽  
Optical Mapping ◽  
Calcium Transient ◽  
Automated Analysis ◽  
Calcium Transients ◽  
Data Sets ◽  
User Input ◽  
Core Feature ◽  
Mapping Analysis

AbstractOptical mapping is widely used in experimental cardiology, as it allows visualization of cardiac membrane potential and calcium transients. However, optical mapping measurements from a single heart or cell culture can produce several gigabytes of data, warranting automated computer analysis. Here we present COSMAS, a software toolkit for automated analysis of optical mapping recordings in cardiac preparations. COSMAS generates activation and conduction velocity maps, as well as visualizations of action potential and calcium transient duration, S1-S2 protocol analysis, and alternans mapping. The software is built around our recent ‘comb’ algorithm for segmentation of action potentials and calcium transients, offering excellent performance and high resistance to noise. A core feature of our software is that it is based on scripting as opposed to relying on a graphical user interface for user input. The central role of scripts in the analysis pipeline enables batch processing and promotes reproducibility and transparency in the interpretation of large cardiac data sets. Finally, the code is designed to be easily extended, allowing researchers to add functionality if needed. COSMAS is provided in two languages, Matlab and Python, and is distributed with a user guide and sample scripts, so that accessibility to researchers is maximized.

Development and production experience of the multilayer curtain-coated linerboard of Ji’an PM No. 3,

TAPPI Journal ◽  
2014 ◽  
Vol 13 (2) ◽  
pp. 17-25
Author(s):  
JUNMING SHU ◽  
ARTHAS YANG ◽  
PEKKA SALMINEN ◽  
HENRI VAITTINEN
Keyword(s):  
Titanium Dioxide ◽  
High Speed ◽  
Food Packaging ◽  
Production Efficiency ◽  
Positive Impact ◽  
Low Cost ◽  
Board Structure ◽  
Flexographic Printing ◽  
Curtain Coating ◽  
Coating Formulations

The Ji’an PM No. 3 is the first linerboard machine in China to use multilayer curtain coating technology. Since successful startup at the end of 2011, further development has been carried out to optimize running conditions, coating formulations, and the base paper to provide a product with satisfactory quality and lower cost to manufacture. The key challenges include designing the base board structure for the desired mechanical strength, designing the surface properties for subsequent coating operations, optimizing the high-speed running of the curtain coater to enhance production efficiency, minimizing the amount of titanium dioxide in the coating color, and balancing the coated board properties to make them suitable for both offset and flexographic printing. The pilot and mill scale results show that curtain coating has a major positive impact on brightness, while smoothness is improved mainly by the blade coating and calendering conditions. Optimization of base board properties and the blade + curtain + blade concept has resulted in the successful use of 100% recycled fiber to produce base board. The optical, mechanical, and printability properties of the final coated board meet market requirements for both offset and flexographic printing. Machine runnability is excellent at the current speed of 1000 m/min, and titanium dioxide has been eliminated in the coating formulations without affecting the coating coverage. A significant improvement in the total cost of coated white liner production has been achieved, compared to the conventional concept of using virgin fiber in the top ply. Future development will focus on combining low cost with further quality improvements to make linerboard suitable for a wider range of end-use applications, including frozen-food packaging and folding boxboard.

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