Spiky: An ImageJ Plugin for Data Analysis of Functional Cardiac and Cardiomyocyte Studies.

Introduction And Objective: Nowadays, investigations of heart physiology and pathophysiology rely more and more upon image analysis, whether for the detection and characterization of events in single cells or for the mapping of events and their characteristics across an entire tissue. These investigations require extensive skills in image analysis and/or expensive software, and their reproducibility may be a concern. Our objective was to build a robust, reliable and open-source software tool to quantify excitation-contraction related experimental data at multiple scales, from single isolated cells to the whole heart.

Structural heterogeneity of the rat pulmonary vein myocardium: consequences on intracellular calcium dynamics and arrhythmogenic potential.

Mechanisms underlying ectopic activity in the pulmonary vein (PV) which triggers paroxysmal atrial fibrillation are unknown. Although several studies have suggested that calcium signalling might be involved in these arrhythmias, little is known about calcium cycling in PV cardiomyocytes (CM). We found that individual PV CM showed a wide range of transverse tubular incidence and organization, going from their virtual absence, as described in atrial CM, to well transversally organised tubular systems, like in ventricular CM.

SarConfoCal: simultaneous sarcomere length and cytoplasmic calcium measurements for laser scanning confocal microscopy images.

Summary: Simultaneous recordings of myocytes contractility and their cytoplasmic calcium concentration allow powerful studies, particularly on heart failure and other cardiac dysfunctions. Such studies require dedicated and expensive experimental devices that are difficult to use. Thus we propose SarConfoCal, the first and only software to simultaneously analyse both cytoplasmic calcium variations (from fluorescence signal) and myocytes contractility (from sarcomere length measurement) on laser scanning confocal microscopy images.

SarcOptiM for ImageJ: high-frequency online sarcomere length computing on stimulated cardiomyocytes.

Accurate measurement of cardiomyocyte contraction is a critical issue for scientists working on cardiac physiology and physiopathology of diseases implying contraction impairment. Cardiomyocytes contraction can be quantified by measuring sarcomere length, but few tools are available for this, and none is freely distributed. We developed a plug-in (SarcOptiM) for the ImageJ/Fiji image analysis platform developed by the National Institutes of Health.

Automatic quantitative analysis of t-tubule organization in cardiac myocytes using ImageJ.

The transverse tubule system in mammalian striated muscle is highly organized and contributes to optimal and homogeneous contraction. Diverse pathologies such as heart failure and atrial fibrillation include disorganization of t-tubules and contractile dysfunction. Few tools are available for the quantification of the organization of the t-tubule system.