Electrical Stimulation for Low-Energy Termination of Cardiac Arrhythmias: a Review

2021 ◽  
Author(s):  
Skylar Buchan ◽  
Ronit Kar ◽  
Mathews John ◽  
Allison Post ◽  
Mehdi Razavi
Keyword(s):  
Electrical Stimulation ◽  
Cardiac Arrhythmias ◽  
Low Energy

scholarly journals Internal transvenous low energy cardioversion for the treatment of cardiac arrhythmias.

Heart ◽  
1984 ◽  
Vol 52 (4) ◽  
pp. 377-384 ◽  
Author(s):  
A W Nathan ◽  
R S Bexton ◽  
R A Spurrell ◽  
A J Camm
Keyword(s):  
Cardiac Arrhythmias ◽  
Low Energy ◽  
Low Energy Cardioversion

Cardiac arrhythmias induced by an electrical stimulation at a cellular level

2008 ◽  
Author(s):  
S. Jacquir ◽  
S. Binczak ◽  
D. Vandroux ◽  
G. Laurent ◽  
P. Athias ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Cardiac Arrhythmias ◽  
Cellular Level

Mechanism of cardiac arrhythmias induced by diencephalic stimulation

1962 ◽  
Vol 203 (6) ◽  
pp. 1120-1124 ◽  
Author(s):  
John W. Manning ◽  
Marion deV. Cotten
Keyword(s):  
Electrical Stimulation ◽  
Vagus Nerve ◽  
Cardiac Arrhythmias ◽  
Stellate Ganglion ◽  
Vagus Nerves ◽  
Sinus Rate ◽  
Electrocardiographic Changes ◽  
Bilateral Vagotomy ◽  
The Right ◽  
Stimulation Of

Electrical stimulation of numerous areas in the midbrain reticular formation and in the posterior hypothalamus of the cat increased blood pressure and caused a variety of electrocardiographic changes, including sinus tachycardia, ventricular premature contractions, bigeminal rhythm, A-V dissociation, and ventricular tachycardia. Most commonly, these arrhythmias developed immediately after cessation of diencephalic stimulation but also developed during the period of stimulation in 5 of the 23 cats studied. The arrhythmias disappeared upon cooling and reappeared upon rewarming the vagus nerves. The arrhythmias also were abolished by methylscopolamine, by bilateral vagotomy, or by extirpation of the stellate ganglia. Electrical stimulation of the distal end of the cut right vagus nerve slowed the sinus rate and electrical stimulation of the right stellate ganglion elevated sinus rate, but neither of these procedures caused arrhythmias. Simultaneous stimulation of both the right vagus nerve and the right stellate ganglion, however, caused arrhythmias similar to those observed after diencephalic stimulation. These data are interpreted to indicate that the cardiac arrhythmias evoked by diencephalic stimulation result from the interplay of both sympathetic and parasympathetic influences on the heart.

Dissociated Σ=27 boundaries in silicon

1988 ◽  
Vol 46 ◽  
pp. 624-625
Author(s):  
A. Garg ◽  
W.A.T. Clark ◽  
J.P. Hirth
Keyword(s):  
Electron Diffraction ◽  
Local Minimum ◽  
Boundary Energy ◽  
Coincidence Site Lattice ◽  
Boundary Plane ◽  
Low Energy ◽  
Theoretical Understanding ◽  
Site Lattice ◽  
Kikuchi Pattern ◽  
Analysis Techniques

In the last twenty years, a significant amount of work has been done in the theoretical understanding of grain boundaries. The various proposed grain boundary models suggest the existence of coincidence site lattice (CSL) boundaries at specific misorientations where a periodic structure representing a local minimum of energy exists between the two crystals. In general, the boundary energy depends not only upon the density of CSL sites but also upon the boundary plane, so that different facets of the same boundary have different energy. Here we describe TEM observations of the dissociation of a Σ=27 boundary in silicon in order to reduce its surface energy and attain a low energy configuration.The boundary was identified as near CSL Σ=27 {255} having a misorientation of (38.7±0.2)°/[011] by standard Kikuchi pattern, electron diffraction and trace analysis techniques. Although the boundary appeared planar, in the TEM it was found to be dissociated in some regions into a Σ=3 {111} and a Σ=9 {122} boundary, as shown in Fig. 1.

Transfer optics for high spatial resolution electron spectroscopy

1988 ◽  
Vol 46 ◽  
pp. 666-667
Author(s):  
G. G. Hembree ◽  
Luo Chuan Hong ◽  
P.A. Bennett ◽  
J.A. Venables
Keyword(s):  
Magnetic Field ◽  
Scanning Transmission Electron Microscope ◽  
Low Energy ◽  
Objective Lens ◽  
State University ◽  
Arizona State University ◽  
Initial Field ◽  
Resolution Electron ◽  
Scanning Transmission ◽  
Low Energy Electrons

A new field emission scanning transmission electron microscope has been constructed for the NSF HREM facility at Arizona State University. The microscope is to be used for studies of surfaces, and incorporates several surface-related features, including provision for analysis of secondary and Auger electrons; these electrons are collected through the objective lens from either side of the sample, using the parallelizing action of the magnetic field. This collimates all the low energy electrons, which spiral in the high magnetic field. Given an initial field Bi∼1T, and a final (parallelizing) field Bf∼0.01T, all electrons emerge into a cone of semi-angle θf≤6°. The main practical problem in the way of using this well collimated beam of low energy (0-2keV) electrons is that it is travelling along the path of the (100keV) probing electron beam. To collect and analyze them, they must be deflected off the beam path with minimal effect on the probe position.

The “KIMWIPE” Effect in Ultra-Thin Cryosections

1985 ◽  
Vol 43 ◽  
pp. 458-459
Author(s):  
I. Taylor ◽  
P. Ingram ◽  
J.R. Sommer
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Muscle Fibers ◽  
Ice Crystals ◽  
Crystal Formation ◽  
Ice Crystal ◽  
Thin Sections ◽  
Skeletal Muscle Fibers ◽  
Freeze Dried ◽  
Ice Crystal Formation

In studying quick-frozen single intact skeletal muscle fibers for structural and microchemical alterations that occur milliseconds, and fractions thereof, after electrical stimulation, we have developed a method to compare, directly, ice crystal formation in freeze-substituted thin sections adjacent to all, and beneath the last, freeze-dried cryosections. We have observed images in the cryosections that to our knowledge have not been published heretofore (Figs.1-4). The main features are that isolated, sometimes large regions of the sections appear hazy and have much less contrast than adjacent regions. Sometimes within the hazy regions there are smaller areas that appear crinkled and have much more contrast. We have also observed that while the hazy areas remain still, the regions of higher contrast visibly contract in the beam, often causing tears in the sections that are clearly not caused by ice crystals (Fig.3, arrows).

Performance Evaluation of a Novel Type of Low-Energy Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 354-355
Author(s):  
Bertholdand Senftinger ◽  
Helmut Liebl
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Field Strength ◽  
Numerical Aperture ◽  
Low Energy ◽  
Energy Electron ◽  
High Resolution Imaging ◽  
Lens System ◽  
Resolution Imaging ◽  
Low Energy Electron

During the last few years the investigation of clean and adsorbate-covered solid surfaces as well as thin-film growth and molecular dynamics have given rise to a constant demand for high-resolution imaging microscopy with reflected and diffracted low energy electrons as well as photo-electrons. A recent successful implementation of a UHV low-energy electron microscope by Bauer and Telieps encouraged us to construct such a low energy electron microscope (LEEM) for high-resolution imaging incorporating several novel design features, which is described more detailed elsewhere.The constraint of high field strength at the surface required to keep the aberrations caused by the accelerating field small and high UV photon intensity to get an improved signal-to-noise ratio for photoemission led to the design of a tetrode emission lens system capable of also focusing the UV light at the surface through an integrated Schwarzschild-type objective. Fig. 1 shows an axial section of the emission lens in the LEEM with sample (28) and part of the sample holder (29). The integrated mirror objective (50a, 50b) is used for visual in situ microscopic observation of the sample as well as for UV illumination. The electron optical components and the sample with accelerating field followed by an einzel lens form a tetrode system. In order to keep the field strength high, the sample is separated from the first element of the einzel lens by only 1.6 mm. With a numerical aperture of 0.5 for the Schwarzschild objective the orifice in the first element of the einzel lens has to be about 3.0 mm in diameter. Considering the much smaller distance to the sample one can expect intense distortions of the accelerating field in front of the sample. Because the achievable lateral resolution depends mainly on the quality of the first imaging step, careful investigation of the aberrations caused by the emission lens system had to be done in order to avoid sacrificing high lateral resolution for larger numerical aperture.

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