background: potassium, as an extracellular ion, plays an important role in the electrophysiologic function of the myocardium and any change in extracellular concentration of this ion might have a marked impression upon myocyte electrophysiologic gain. high serum potassium levels are thought to impair pulse conduction in purkinje fibers and ventricles more than that in the atrioventricular (av) ...

OBJECTIVES The objective of this study was to determine whether the threshold for successful cardiac pacing is affected by electrode impedance and whether this procedure can be successfully carried out through low impedance electrodes that are also suitable for defibrillation. BACKGROUND Reintroduced in the early 1980s, external cardiac pacing utilizes large externally placed electrodes with ...

BACKGROUND Implantable heart rhythm devices are susceptible to interference in hospitals where electromagnetic interference (EMI) sources are ubiquitous. CASE DESCRIPTION We report three cases in which EMI from the external defibrillator caused the inability to interrogate Boston Scientific cardiac resynchronization therapy-pacemaker (CRT-P) devices. We have documented interference with the B...

BACKGROUND Analysis of high gain, signal-averaged (SA) ECG is an accepted method evaluating abnormalities of atrial repolarization--the presence of late potentials (ALP)--predictive for atrial arrhythmias. Recently it has been proven that the location of atrial leads has an influence on atrial activation and modifies the risk of atrial arrhythmias. The aim of our study was to estimate the effec...

The number of pacemakers and implantable cardioverter defibrillators implanted each year continues to grow in Spain, due largely to the increased life expectancy of the population in the case of pacemakers and the indications for primary prevention in the case of implantable cardioverter defibrillators. Although the incidence of infections associated with implantable cardiac devices is not high...

Background: Potassium, as an extracellular ion, plays an important role in the electrophysiologic function of the myocardium and any change in extracellular concentration of this ion might have a marked impression upon myocyte electrophysiologic gain. High serum potassium levels are thought to impair pulse conduction in Purkinje fibers and ventricles more than that in the Atrio...

1. Implantable pulse generators with endocardial or myocardial electrodes for long-term or permanent use. 2. External, miniaturized, transistorized, patientportable, battery-powered, pulse generators with exteriorized electrodes for temporary transvenous endocardial or transthoracic myocardial pacing. 3. Console batteryor AC-powered cardiovertors, defibrillators, or monitors with high-current e...

BACKGROUND Left ventricular (LV) pacing improves hemodynamics in patients with heart failure. We hypothesized that at least part of this benefit occurs by minimization of external constraint to LV filling from ventricular interaction. METHODS AND RESULTS We present median values (interquartile ranges) for 13 heart failure patients with LV pacing systems implanted for New York Heart Associatio...