Although transmural heterogeneity of action potential duration (APD) is established in single cells isolated from different tissue layers, the extent to which it produces transmural gradients of repolarization in electrotonically coupled ventricular myocardium remains controversial. The purpose of this study was to examine the relative contribution of intrinsic cellular gradients of APD and ele...

Effects of the constituents from Ginkgo biloba extract (GBE) on the action potentials and the ionic currents in guinea pig ventricular cardiomyocytes were investigated using whole-cell and current-clamp techniques. The constituents, ginkgolides A, B, C and quercetin, had depressant effects at 0.1-3muM on the action potential configuration. Ginkgolide A (1-3 muM) prolonged the action potential (...

OBJECTIVE Our goal was to study rate adaptation of atrial action potentials in non-steady and steady states to further our understanding of mechanisms determining inducibility and stability of atrial fibrillation. METHODS We used standard microelectrode techniques to examine the characteristics of steady-state action potentials paced at regular cycle lengths (CL) and of nonsteady-state action...

We used intracellular microelectrodes to study the effect of changes in extracellular calcium ion concentration [Ca]o on the transmembrane potentials of canine cardiac Purkinje fibers in control Tyrode's solution and in the presence of agents thought to modify membrane permeability to potassium. In Tyrode's solution, decreasing [Ca]o from 2.7 to 0.9 mM increased action potential duration measur...

OBJECTIVES about 50% of men with antisocial personality disorder (APD) present a comorbid anxiety disorder. Historically, it was thought that anxiety limited criminal activity and the development of APD, but recent evidence suggests that heightened responsiveness to threat may lead to persistent violent behaviour. Our study aimed to determine the prevalence of APD comorbid with anxiety disorder...

In this study, the authors theoretically study the performance of direct-detection free-space optical communication systems using binary phase-shift keying subcarrier-intensity modulation and avalanche photodiode (APD). The system biterror rate and channel capacity are theoretically derived in cases of log-normal and gamma-gamma channel models for weakto-moderate and moderate-to-strong atmosphe...

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...

BACKGROUND Acquired perforating dermatosis (APD) is histopathologically characterized by transepidermal elimination of materials from the upper dermis. APD can be divided into four diseases: Kyrle's disease, perforating folliculitis, elastosis perforans serpiginosa, and reactive perforating collagenosis. APD is usually associated with systemic diseases, especially diabetes mellitus or chronic r...

Thyroid hormones play an important role in cardiac electrophysiology through both genomic and nongenomic mechanisms of action. The effects of triiodothyronine (T(3)) on the electrophysiological properties of ventricular myocytes isolated from euthyroid and hypothyroid rats were studied using whole cell patch clamp techniques. Hypothyroid ventricular myocytes showed significantly prolonged actio...