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Updated: Jun 8, 2026

Measuring Fast Calcium Fluxes in Cardiomyocytes
Published on: November 29, 2011
Phase-2 reentry in cardiac tissue: role of the slow calcium pulse
Inma R Cantalapiedra1, Angelina Peñaranda, Blas Echebarria
1Departament de Física Aplicada, Universitat Politècnica de Catalunya, Av Dr Marañón 44-50, E-08028 Barcelona, Spain.
Abstract:
Phase-2 re-entry is thought to underlie many causes of idiopathic ventricular arrhythmias as, for instance, those occurring in Brugada syndrome. In this paper, we study under which circumstances a region of depolarized tissue can re-excite adjacent regions that exhibit shorter action potential duration (APD), eventually inducing reentry. For this purpose, we use a simplified ionic model that reproduces well the ventricular action potential. With the help of this model, we analyze the conditions that lead to very short action potentials (APs), as well as possible mechanisms for re-excitation in a cable. We then study the induction of re-entrant waves (spiral waves) in simulations of AP propagation in the heart ventricles. We show that re-excitation takes place via a slow pulse produced by calcium current that propagates into the region of short APs until it encounters excitable tissue. We calculate analytically the speed of the slow pulse, and also give an estimate of the minimal tissue size necessary for allowing reexcitation to take place.
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