The local repolarization heterogeneity in the murine pulmonary veins myocardium contributes to the spatial distribution of the adrenergically induced ectopic foci.

An atrial tachyarrhythmias is predominantly triggered by a proarrhythmic activity originate from the pulmonary veins (PV) myocardial sleeves; sympathetic or adrenergic stimulation facilitates PV proarrhythmia. In the present study the electrophysiological inhomogeneity, spatiotemporal characteristics of the adrenergically induced ectopic firing and sympathetic nerves distribution have been investigated in a murine PV myocardium to clarify mechanisms of adrenergic PV ectopy. Electrically paced murine PV demonstrate atrial-like pattern of conduction and atrial-like action potentials (AP) with longest duration in the mouth of PV.

[Electrhopysiological Effect of the Polyamine Spermine in Normoxic and Ischemic Ventricular Myocardium].

Cytoplasmic polyamines (PA) are involved in control of many cellular functions and are well known as regulators of so called inward-rectifier potassium ion channels. Nevertheless, functional significance of extracellular PA in the heart is poorly elucidated. Aim of this study was to study effects of endogenous PA spermine in the ventricular myocardium.

[Types of Conduction Disturbances in Pulmonary Veins].

Recently, the notion that in 60-80 % of cases the origin of the pulmonary veins (PV) is the place of origin of atrial fibrillation (AF) has become widespread. It has been shown that in this area, under the action of norepinephrine (HA), in the absence of stimulation, an intrinsic rhythm appears. Using two-channel microelectrode leads (from the mouth and distal part of the PV) in rats weighing 350-450 grams, it was found that: 1) in the distal part of PV there are cells with depolarized resting potential (RP) up to -50 mV, which under normal conditions are not excitable; 2) in 17 experiments out of 23, various blocks of excitation conduction along PV were revealed; 3) in 8 experiments out of 23, a reflected excitation wave - echo from PV - was recorded.

[Restoration of Sinus Rhythm in Patients With Persistent Atrial Fibrillation and Obesity: New Possibilities of Pharmacological Cardioversion].

We present in this article 2 cases of successful pharmacological restoration of sinus rhythm by a new class III antiarrhythmic drug refralon in patients with obesity and persistent atrial fibrillation. In both cases, the effective use of refralon was preceded by repeated ineffective attempts of electrical cardioversion. In the article we discuss the role of obesity as the factor leading to a substantial increase of transthoracic electrical resistance, and thus significantly reducing the probability of sinus rhythm restoration by means of electrical cardioversion.

[Intracellular Molecular Mechanisms of Adrenergic Regulation of Pulmonary Vein Myocardium Membrane Potential].

Pulmonary vein (PV) myocardium is characterized by numerous electrophysiological properties which make this tissue highly prone to spontaneous, ectopic activity partially due to resting potential (RP) instability. PV derived ectopy frequently underlies supraventricular arrhythmias, including atrial fibrillation. It has also been demonstrated that adrenergic stimulation causes proarrhythmic alterations in PV.