Objectives: To evaluate the possible pain reduction of the plateau waveform in atrial fibrillation (AF) patients.
Background: Previous studies have indicated that reduced amplitude waveforms would be less painful than a conventional (65/65% tilt) biphasic waveform. Computer modeling suggested that a moderately long (10-12 msec) plateau (flat topped) shock waveform would deliver equivalent effectiveness with the lowest possible peak amplitude.
Methods: We enrolled 27 patients at two sites with persistent AF with a total of 220 shocks delivered during internal atrial cardioversion using an interleaved crossover design. Patient response was scored in three ways: (1) a verbally reported discomfort score, (2) visual analog scale (VAS), and (3) a blinded observer reporting a contraction score.
Results: All scores were significantly reduced (P < 0.0001) by the plateau waveform with impressive statistics: Verbal discomfort (3.51 +/- 0.13 to 2.89 +/- 0.12), VAS (7.00 +/- 0.56 to 5.91 +/- 0.36), and contraction scores (1.94 +/- 0.12 to 1.62 +/- 0.12). The average pain threshold shift (TS) for the Verbal score was 2.34, while that for the VAS score was 2.30. (This means that the patient typically could tolerate 2.34 times as much energy with the plateau waveform for the same level of verbally reported discomfort.) The contraction TS was less at 1.57. Response scores were also corrected for the shock sequence number to control for the sensitization effect from multiple shocks. This increased the TS for the Verbal score to 3.58, but the shock number was not significant for the VAS. A pulmonary artery electrode return was associated with lower pain compared with a coronary sinus position.
Conclusion: A plateau shaped biphasic waveform resulted in significantly increased shock energy pain tolerances. Controlling for session sensitization, patients tolerated over three times as much energy for the same verbally reported discomfort score.
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http://dx.doi.org/10.1111/j.1540-8167.2007.00846.x | DOI Listing |
Int J Radiat Oncol Biol Phys
November 2024
Department of Radiology, Nagoya City University Graduate School of Medical Sciences.
Purpose: To establish an ultra-high dose-rate (UHDR) radiation system using a synchrotron proton beam accelerator and to compare the effects by irradiation positions on cultured cells and chick embryos.
Methods And Materials: Protons for UHDR were obtained by applying high-frequency power at much higher levels than usual to extract all protons within approximately 50 ms. Subsequently, monitoring with a Faraday cup was performed immediately after synchrotron extraction and the waveform was adjusted accordingly.
Brain Spine
July 2024
Department of Clinical Physics and Bioengineering, NHS Greater Glasgow and Clyde, Scotland, United Kingdom.
Introduction: Intracranial pressure (ICP) monitoring is commonly used in investigating the aetiology of chronic paediatric neurological conditions. A series of high-amplitude spikes has been observed in overnight ICP recordings of some children, many of whom have hydrocephalus or craniosynostosis.
Research Question: This clinical evaluation aimed to define the spike pattern, describe the patient group in which it is most likely to occur, and conduct high-resolution waveform analysis.
Research (Wash D C)
August 2024
Department of Engineering Physics, Tsinghua University, Beijing 100084, China.
The emergence of multi-petawatt laser facilities is expected to push forward the maximum energy gain that can be achieved in a single stage of a laser wakefield acceleration (LWFA) to tens of giga-electron volts, which begs the question-is it likely to impact particle physics by providing a truly compact particle collider? Colliders have very stringent requirements on beam energy, acceleration efficiency, and beam quality. In this article, we propose an LWFA scheme that can for the first time simultaneously achieve hitherto unrealized acceleration efficiency from the laser to the electron beam of >20% and a sub-1% energy spread using a stepwise plasma structure and a nonlinearly chirped laser pulse. Three-dimensional high-fidelity simulations show that the nonlinear chirp can effectively mitigate the laser waveform distortion and lengthen the acceleration distance.
View Article and Find Full Text PDFSensors (Basel)
July 2024
State Key Laboratory of the Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
Compelling evidence has shown that geomagnetic disturbances in vertical intensity polarization before great earthquakes are promising precursors across diverse rupture conditions. However, the geomagnetic vertical intensity polarization method uses the spectrum of smooth signals, and the anomalous waveforms of seismic electromagnetic radiation, which are basically nonstationary, have not been adequately considered. By combining pulse amplitude analysis and an experimental study of the cumulative frequency of anomalies, we found that the pulse amplitudes before the 2022 Luding M6.
View Article and Find Full Text PDFJ Neurosci Methods
September 2024
Institute for Medical Engineering & Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. Electronic address:
Background: Significant research has been devoted to developing noninvasive approaches to neuromonitoring. Clinical validation of such approaches is often limited, with minimal data available in the clinically relevant elevated ICP range.
New Method: To allow ultrasound-guided placement of an intraventricular catheter and to perform simultaneous long-duration ICP and ultrasound recordings of cerebral blood flow, we developed a large unilateral craniectomy in a swine model.
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