Are Atrial High-rate Episodes a Kind of Sympathetic Overactivity in Patient with Permanent Pacemaker?

Objective: The present study aims to investigate the incidence and predictors of atrial high-rate events (AHREs) in patients with permanent pacemaker implants.Methods: A total of 289 patients who were implanted with a dual-chamber pacemaker due to complete atrioventricular block or symptomatic sick sinus syndrome (SSS) and had no previous history of atrial fibrillation were included in the present study. AHREs are defined as events with an atrial frequency of ≥175 bpm and a duration of ≥5 min. The patients were divided into two groups according to whether or not AHREs were detected during the follow-up: group A (AHRE+, n = 91) and group N (AHRE–, n = 198).Results: During the 12-month follow-up period, AHREs were detected in 91 patients (31.5%). The multivariate Cox regression analysis revealed that patient age [odds ratio [OR] = 1.041; 95% confidence interval [CI], 1.018–1.064; and P < 0.001], pacemaker implantation due to symptomatic SSS (OR = 2.225; 95% CI, 1.227–4.036; and P = 0.008), and the percentage of atrial pacing after pacemaker implantation (OR = 1.010; 95% CI, 1.002–1.017; and P = 0.016) were independent AHRE predictors.Conclusion: The AHRE detection rate in patients with pacemaker implants was 31.5%. Patient age, pacemaker implantation due to symptomatic SSS, and the percentage of atrial pacing after pacemaker implantation were independent AHRE predictors.

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High-rate episodes with simultaneous atrial and ventricular activation in a patient with permanent pacemaker implantation for complete heart block

HeartRhythm Case Reports ◽

10.1016/j.hrcr.2019.10.013 ◽

2020 ◽

Vol 6 (2) ◽

pp. 67-71

Author(s):

Saurabh Ajit Deshpande ◽

Ameya Udyavar

Keyword(s):

Heart Block ◽

Complete Heart Block ◽

Pacemaker Implantation ◽

Permanent Pacemaker ◽

High Rate ◽

Permanent Pacemaker Implantation ◽

Ventricular Activation

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Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069272 ◽

1970 ◽

Vol 28 ◽

pp. 456-457

Author(s):

L. E. Murr ◽

G. Wong

Keyword(s):

Single Crystal ◽

High Vacuum ◽

Ultra High Vacuum ◽

High Rate ◽

Flash Evaporation ◽

Optimum Load ◽

Single Crystal Films ◽

Crystal Films ◽

A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

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Rapid Freezing of Freeze-Etch Specimens

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600003275 ◽

1980 ◽

Vol 38 ◽

pp. 752-755

Author(s):

A. Elgsaeter ◽

T. Espevik ◽

G. Kopstad

Keyword(s):

Low Temperature ◽

Metal Surface ◽

Relative Velocity ◽

Thermal Contact ◽

High Rate ◽

Rapid Freezing ◽

Temperature Decrease ◽

Freeze Etching

The importance of a high rate of temperature decrease (“rapid freezing”) when freezing specimens for freeze-etching has long been recognized1. The two basic methods for achieving rapid freezing are: 1) dropping the specimen onto a metal surface at low temperature, 2) bringing the specimen instantaneously into thermal contact with a liquid at low temperature and subsequently maintaining a high relative velocity between the liquid and the specimen. Over the last couple of years the first method has received strong renewed interest, particularily as the result of a series of important studies by Heuser and coworkers 2,3. In this paper we will compare these two freezing methods theoretically and experimentally.

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