Electrical signals affect the cardiomyocyte transcriptome independently of contraction.

Cardiomyocytes in vivo are continuously subjected to electrical signals that evoke contractions and instigate drastic changes in the cells' morphology and function. Studies on how electrical stimulation affects the cardiac transcriptome have remained limited to a small number of heart-specific genes. Furthermore, these studies have ignored the interplay between the electrical excitation and the subsequent contractions.

Electrical stimulation of primary neonatal rat ventricular cardiomyocytes using pacemakers.

The study of gene regulation in cardiac myocytes requires a reliable in vitro model. However, monolayer cultures used for this purpose are typically not exposed to electrical stimulation, though this has been shown to strongly affect cardiomyocyte gene expression. Based on pacemakers for clinical use, we developed an easy-to-use portable system that allows the user to perform electro-stimulation of cardiomyocyte cultures in standard tissue incubators without the need for bulky equipment.

Making post-mortem implantable cardioverter defibrillator explantation safe.

Aims: The aim of this study is to investigate whether protection with rubber or plastic gloves during post-mortem explantation of an implantable cardioverter defibrillator (ICD) offers enough protection for the explanting operator during a worst-case scenario (i.e. ICD shock).

Evaluation of cumulative effects of MR imaging on pacemaker systems at 1.5 Tesla.

Background: The purpose of this study was to evaluate possible cumulative effects of repeated magnetic resonance imaging (MRI) examinations on pacemaker systems in patients with cardiac pacemakers.

Methods And Results: The records of pacemaker patients who underwent repetitive MRI examinations in our institution were reviewed to identify patients who underwent two or more MRI examinations at 1.5T of any anatomical region.

Strategy for safe performance of extrathoracic magnetic resonance imaging at 1.5 tesla in the presence of cardiac pacemakers in non-pacemaker-dependent patients: a prospective study with 115 examinations.

Background: The purpose of the present study was to evaluate a strategy for safe performance of extrathoracic magnetic resonance imaging (MRI) in non-pacemaker-dependent patients with cardiac pacemakers.

Methods And Results: Inclusion criteria were presence of a cardiac pacemaker and urgent clinical need for an MRI examination. Pacemaker-dependent patients and those requiring examinations of the thoracic region were excluded.

In vivo heating of pacemaker leads during magnetic resonance imaging.

Aims: Magnetic resonance imaging (MRI) is well established as an important diagnostic tool in medicine. However, the presence of a cardiac pacemaker is usually regarded as a contraindication for MRI due to safety reasons. In this study, heating effects at the myocardium-pacemaker lead tip interface have been investigated in a chronic animal model during MRI at 1.

Pacing in high field cardiac magnetic resonance imaging:

Currently, cardiac MRI is contraindicated in patients with an implanted pacemaker or ICD due to safety hazards. However, MRI is promising to play a key role in cardiac diagnostics in near future. This study examined a rat with an implanted pacemaker pacing at a rate of 460/min with high field cardiac MRI.

Pacemaker reed switch behavior in 0.5, 1.5, and 3.0 Tesla magnetic resonance imaging units: are reed switches always closed in strong magnetic fields?

MRI is established as an important diagnostic tool in medicine. However, the presence of a cardiac pacemaker is usually regarded as a contraindication for MRI due to safety reasons. The aim of this study was to investigate the state of a pacemaker reed switch in different orientations and positions in the main magnetic field of 0.

RV function in stable and unstable VT: is there a need for hemodynamic monitoring in future defibrillators?

During electrophysiological investigation of 22 patients with VT or aborted sudden cardiac death, arterial and RV pressures were measured. The time courses of mean arterial pressure (MAP), RV pulse pressure (RVPP), RV pulse pressure integral (RVPPI), and maximum right ventricular dP/dt (RV dP/dtmax) were followed during the first 15 seconds after VT induction. Compared to basal (preinduction) conditions, the RVPPI decreased by 41+/-10% (mean +/- SD) after 10-15 seconds of VT in 11 patients with stable VT and by 75+/-8% in 11 patients with unstable VT (MAP < 60 mmHg 15 s after VT onset).