Cardiac myocytes are excitable cells in which an external current stimulus depolarizes the membrane potential to elicit an action potential. This action potential then triggers calcium release from intracellular stores, which mediates contraction. Con . . .

When a cardiac cell is rapidly paced it can exhibit a beat-to-beat alternation in the action potential duration (APD) and the intracellular calcium transient. This dynamical instability at the cellular level has been shown to correlate with the genesi . . .

Spatially discordant alternans in membrane voltage (Vm) and intracellular calcium (Cai) is linked to fatal arrhythmias. Two mechanisms for the genesis of discordant alternans have been proposed, i.e., dynamical instability due to conduction velocity ( . . .

The L-type Ca current (ICa,L), essential for normal cardiac function, also regulates dynamic action potential (AP) properties that promote ventricular fibrillation. Blocking ICa,L can prevent ventricular fibrillation, but only at levels suppressing co . . .

Alternans, a condition in which there is a beat-to-beat alternation in the electromechanical response of a periodically stimulated cardiac cell, has been linked to the genesis of life-threatening ventricular arrhythmias. Optical mapping of membrane vo . . .

Mathematical modeling of the cardiac action potential has proven to be a powerful tool for illuminating various aspects of cardiac function, including cardiac arrhythmias. However, no currently available detailed action potential model accurately repr . . .

In homogenous tissue, conduction velocity restitution (CVR) is required for the development of spatially discordant alternans (SDA) except after an ectopic beat. We hypothesized that global capture of monolayers would eliminate CV gradients and SDA wo . . .

In cardiomyocytes, the calcium (Ca) sensitivity of sarcoplasmic reticulum (SR)-bound ryanodine receptor (RyR) channels leads to autocatalytic release of the SR Ca load. Experimental whole-cell data show release from SR to be a high-gain, graded respon . . .

Ventricular fibrillation (VF) is characterized by multiple reentrant waves promoted by both dynamical instabilities and anatomical heterogeneities. Decreasing dynamic wave instability by flattening action potential duration restitution (APDR) slope wi . . .

Ventricular fibrillation (VF), a leading cause of sudden cardiac death, is due multiple re-entrant waves created as a result of spiral wave break-up. Dynamic wave instabilities can cause spontaneous wavebreak, leading to a fibrillation like state even . . .