Human sodium current voltage-dependence at physiological temperature measured by coupling a patch-clamp experiment to a mathematical model.

Voltage-gated Na channels are crucial to action potential propagation in excitable tissues. Because of the high amplitude and rapid activation of the Na current, voltage-clamp measurements are very challenging and are usually performed at room temperature. In this study, we measured Na current voltage-dependence in stem cell-derived cardiomyocytes at physiological temperature.

An atlas of transcribed human cardiac promoters and enhancers reveals an important role of regulatory elements in heart failure.

A deeper knowledge of the dynamic transcriptional activity of promoters and enhancers is needed to improve mechanistic understanding of the pathogenesis of heart failure and heart diseases. In this study, we used cap analysis of gene expression (CAGE) to identify and quantify the activity of transcribed regulatory elements (TREs) in the four cardiac chambers of 21 healthy and ten failing adult human hearts. We identified 17,668 promoters and 14,920 enhancers associated with the expression of 14,519 genes.

Open-source low-cost cardiac optical mapping system.

Fluorescent imaging with voltage- or calcium-sensitive dyes, known as optical mapping, is one of the indispensable modern techniques to study cardiac or neural electrophysiology, unsurpassed by temporal and spatial resolution. High-speed CMOS cameras capable of optical registration of action potential propagation are in general very costly. We present a complete solution priced below US$1,000 (including camera and lens) at the moment of publication with an open-source image acquisition and processing software.

Correction: Genetic algorithm-based personalized models of human cardiac action potential.

[This corrects the article DOI: 10.1371/journal.pone.

Genetic algorithm-based personalized models of human cardiac action potential.

We present a novel modification of genetic algorithm (GA) which determines personalized parameters of cardiomyocyte electrophysiology model based on set of experimental human action potential (AP) recorded at different heart rates. In order to find the steady state solution, the optimized algorithm performs simultaneous search in the parametric and slow variables spaces. We demonstrate that several GA modifications are required for effective convergence.