INTRODUCTION. MR imaging of the heart and thoracic vessels requires ECG gating to compensate for cardiac motion. Triggering is accomplished by synchronizing the image acquisition pulse sequence to the R-wave of the ECG. However, the magnetic fields within the bore of the scanner can cause artifacts in the ECG waveform which result in gating errors. In addition, small variations in electrode pos...

Mouse cardiac MR gating using ECG is affected by the hostile MR environment. It requires appropriate signal processing and correct QRS detection, but gating software methods are currently limited. In this study we sought to demonstrate the feasibility of digital real-time automatically updated gating methods, based on optimizing a signal-processing technique for different mouse strains. High-re...

Synopsis We investigate the feasibility of using 2-D self-navigation for respiratory gating for free-breathing whole-heart 3-D CINE imaging, where respirationinduced cardiac motion may be more easily detected than in commonly used 1-D self-navigation methods. We compare self-navigation images, derived gating signals and resulting 3-D CINE images of the 1-D and 2-D methods and nd that respirator...

ProTx-II, an inhibitory cysteine knot toxin from the tarantula Thrixopelma pruriens, inhibits voltage-gated sodium channels. Using the cut-open oocyte preparation for electrophysiological recording, we show here that ProTx-II impedes movement of the gating charges of the sodium channel voltage sensors and reduces maximum activation of sodium conductance. At a concentration of 1 microM, the toxi...

We aimed to study kinetics of modulation by intracellular Mg(2+) of cardiac gap junction (Mg(2+) gate). Paired myocytes of guinea-pig ventricle were superfused with solutions containing various concentrations of Mg(2+). In order to rapidly apply Mg(2+) to one aspect of the gap junction, the non-junctional membrane of one of the pair was perforated at nearly the connecting site by pulses of nitr...

Background The current clinical standard in cardiac functional MRI is retrospectively gated cine MRI. The technique is relying on a regular heart beat and cardiac cycles showing substantial deviation from the mean heart rate are excluded, often causing reduced image quality and completely suppressing arrhythmic cycles. We introduce a new correlation based self-gating approach enabling reconstru...

Background Suppressing cardiac and respiratory motion artifacts are major challenges in cardiac MRI. The conventional methods of ECG and diaphragm navigator gating require tedious setup, reduce the imaging efficiency significantly, are susceptible to drifts in heart rate or respiratory pattern, and can be unreliable at higher field strengths [1]. In this work, we propose a fully self-gated 4D i...

In general, high spatial and temporal resolutions in cine cardiac imaging require long scan times, making breath-hold acquisition impossible in many cases. To enable free-breathing cardiac imaging, methods such as navigator gating were developed to reduce image artifacts due to respiratory motion. Nevertheless, residual image blurring is seen in images acquired late in the cardiac cycle. Image ...

The aim of the present study was to investigate the single-channel properties of different gating modes in the native human cardiac Na+ channel. Patch-clamp experiments were performed at low noise using ultrathick-walled pipettes. In 17 cell-attached patches containing only one channel, fast back and forth switching between five different Na+-channel gating modes (F-mode, M1-mode, M2-mode, S-mo...