Using a new method for long-term recording of monophasic action potentials from the human heart, we studied in 17 patients the effects on ventricular action potential duration (APD) of three clinically pertinent cycle length perturbations: (1) single extrastimuli, (2) abrupt sustained rate acceleration and deceleration, and (3) different steady-state cycle lengths. Results were: (a) APD after s...

It is known, from both experiments and simulations, that cardiac action potentials are shortened near a non-conducting boundary. In the present paper, this effect is studied in a simple, two-current ionic model, with propagation restricted to a 1D fibre. An asymptotic approximation for the dependence of action potential duration on distance to the boundary is derived. This estimate agrees well ...

The nuclear expression and action of the nuclear factor kappa B (NF-kappaB) transcription factor requires signal-coupled phosphorylation and degradation of the IkappaB inhibitors, which normally bind and sequester this pleiotropically active factor in the cytoplasm. The subsequent molecular events that regulate the termination of nuclear NF-kappaB action remain poorly defined, although the acti...

The involvement of the AGC protein kinase family in regulating arrhythmia has drawn considerable attention, but the underlying mechanisms are still not clear. The aim of this study is to explore the role of 3-phosphoinositide-dependent protein kinase-1 (PDK1), one of upstream protein kinases of the AGC protein kinase family, in the pathogenesis of dysregulated electrophysiological basis. PDK1(F...

Perceiving the sensory consequences of action accurately is essential for appropriate interaction with our physical and social environments. Prediction mechanisms are considered necessary for fine-tuned sensory control of action, yet paradoxically may distort perception. Here, we examine this paradox by addressing how movement influences the perceived duration of sensory outcomes congruent with...

The effects of lidocaine and quinidine on rabbit cardiac Purkinje fibers were compared at 37 °C, using action potential and voltage clamp measurements. At therapeutic concentrations (5 /ig/ml), lidocaine shortened the duration of the action potential while quinidine lengthened it. When membrane potential was held constant between —40 and —50 mV by the application of the two-microelectrode volta...

This review examines the putative role played by three repolarising potassium currents, namely the transient outward current (ito), the inward rectifying current (iK1), and the late outward rectifying current (iK), in the regulation of action potential duration in cardiac Purkinje and ventricular muscle fibres under normal physiological conditions. The role of other potassium currents, includin...

insurer companies frequently reinsure part of their risks before reinsurers. the question of right of action of the insured against the reinsurer then arises. the common response to this question is negative because of the principle of the privacy of contracts. however, courts, particularly in the united states, have recognized this direct action on various grounds, especially in case of insolv...