Quantitative analysis of cardiac electrical restitution.

Electrical restitution (ER) of cardiac cells is an aggregate of events that rhythmically restore the initial conditions of electric signal (action potential) generation. Its analysis represents an important insight into cardiac arrhythmogenesis. The aim of this work is to theoretically substantiate and verify a novel approach allowing for the quantification of the individual ionic current components of ER.

Control of cardiac performance by Ca-turnover.

A quantitative model of Ca-turnover in cardiac cells that incorporates negative feedback modulation of sarcolemmal calcium transport (via Ca channels and Na/Ca exchange) has been designed. The Na/Ca exchange current was expressed as INaCa = INaCar + delta INaCa. The component INaCar reflects slow changes of Ca2+ and Na+ concentrations and depends on the Na/K pump.