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  • 1
    Electronic Resource
    Electronic Resource
    350 Main Street , Malden , MA 02148-5018 , USA , and 9600 Garsington Road , Oxford OX4 2DQ , UK . : Blackwell Science Inc
    Journal of cardiovascular electrophysiology 14 (2003), S. 0 
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Introduction: The combined role of atrial septal lead location and atrial pacing algorithms in the prevention of atrial tachyarrhythmias (AT/AF), including both atrial fibrillation and flutter, is unknown. We tested the hypothesis that atrial prevention pacing algorithms could decrease AT/AF frequency in patients with atrial septal leads, bradycardia, and paroxysmal AT/AF. Methods and Results: A total of 298 patients (age 70 ± 10 years; 61% male) from 35 centers were implanted with a DDDRP pacing system including three AT/AF prevention pacing algorithms. Lead site was randomized at implant to right atrial septal or nonseptal. Patients were randomized 1 month postimplant to AT/AF prevention ON or OFF for 3 months and then crossed over for 3 months. Patients logged symptomatic AT/AF episodes via a manual activator. Prevention efficacy was evaluated based on intention-to-treat in 277 patients (138 septal) with complete follow-up. No changes in device-recorded AT/AF frequency or burden were observed with algorithms OFF versus ON or between patients randomized to septal versus nonseptal lead location. Analysis of other secondary outcomes revealed that AT/AF prevention pacing resulted in decreased atrial premature contractions in both the septal (1.9 [0.2–8.7] vs 3.3 [0.3–10.6]× 103/day; P 〈 0.01) and nonseptal groups (0.9 [0.2–3.3] vs 1.3 [0.3–5.5]× 103/day; P 〈 0.001). Patients with septal leads had fewer symptomatic AT/AF episodes ON versus OFF (1.4 ± 3.0 vs 2.5 ± 5.2/month, P = 0.01). Conclusion: The combination of three atrial prevention pacing algorithms did not decrease device classified atrial tachyarrhythmia frequency or burden during a 3-month cross-over period in bradycardic patients and septal or nonseptal atrial pacing leads. Prevention pacing was associated with decreased frequency of premature atrial contractions and with decreased symptomatic atrial tachyarrhythmia frequency in patients with atrial septal leads. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1189-1195, November 2003)
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Cambridge : Emerald
    Foresight 4 (2002), S. 13-30 
    ISSN: 1465-9832
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Political Science
    Notes: This essay examines the issues that the ongoing revolution in biosciences and biotechnology pose to social science. A convenient frame for examining these issues is the framework of "thematic priorities" established by the British funding agency for social science, the Economic and Social Research Council (ESRC). These "thematic priorities" are used to identify major challenges and opportunities that currently confront social research. Though not constructed as part of a futures exercise, this framework proved useful for organising the issues that were generated from literature review and brainstorming, provided a stimulus to identify new issues, and was a useful filter for presenting results to the ESRC, which sponsored the study. This range of issues does not just call for interaction between natural and social scientists: there is also need for the sharing of knowledge and perspectives across diverse fields of social science. In order to help inform future research priorities, we need to move beyond the perspectives of single disciplines, and make sure that we do not simply emphasise those areas where social scientists have already been actively engaged. The study concludes clearly that there is a huge range of vital questions that social science needs to address if we are to understand, let alone bring more social intelligence to bear on shaping, the scientific and technological revolutions that are under way, and their broader social implications.
    Type of Medium: Electronic Resource
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  • 3
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    Ann Arbor, Mich., etc. : Periodicals Archive Online (PAO)
    Notes. [ser.2]:48:1 (1991:Sept.) 124 
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  • 4
    facet.materialart.
    Unknown
    Ann Arbor, Mich., etc. : Periodicals Archive Online (PAO)
    Notes. [ser.2]:48:1 (1991:Sept.) 124 
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  • 5
    facet.materialart.
    Unknown
    Ann Arbor, Mich., etc. : Periodicals Archive Online (PAO)
    Notes. [ser.2]:48:1 (1991:Sept.) 124 
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  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature biotechnology 22 (2004), S. 807-810 
    ISSN: 1546-1696
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: [Auszug] In the December 14, 2001, issue of Science, two articles appeared back-to-back presenting the genome analysis of the same strain of the same organism, Agrobacterium tumefaciens C.58 (refs. 1,2)—a bacterium often termed the 'natural genetic engineer' because of its routine use in plant ...
    Type of Medium: Electronic Resource
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  • 7
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    Unknown
    Sydney, etc. : Periodicals Archive Online (PAO)
    Oceania. 62:3 (1992:Mar.) 228 
    ISSN: 0029-8077
    Topics: Ethnic Sciences
    Description / Table of Contents: REVIEWS
    Notes: SOUTHEAST ASIAN ISSUE
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  • 8
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Impedance Versus Temperature Monitoring. Introduction: The purpose of this study was to prospectively compare the value of impedance and temperature monitoring during accessory pathway ablation. Temperature and impedance monitoring can be used during radiofrequency ablation of accessory pathways to titrate power to achieve adequate but not excessive tissue beating. Methods and Results: One hundred thirty-two patients with a single accessory pathway were randomly assigned to undergo ablation using either impedance monitoring or temperature monitoring. During impedance monitoring, the endpoint for titration of power was a 5-to 10-Ω decrease in the measured impedance while for temperature monitoring the endpoint was to achieve a temperature of 58° to 62°C. Two protocols were used. In protocol 1 (90 patients), impedance monitoring was performed with a nonthermistor catheter and temperature monitoring was performed with a thermistor catheter. In protocol 2 (42 patients), a thermistor catheter was used in all patients. In protocol 1, the success rate (93% vs 93%; P = 1.0), ablation procedure duration (57 ± 56 vs 41 ± 41 min), fluoroscopy time (48 ± 29 vs 41 ± 23 min; P = 0.3), number of applications (6.2 ± 4.7 vs 5.7 ± 4.6; P = 0.8), and the number of applications associated with coagulum formation (0.1 ± 0.3 vs 0.3 ± 0.6; P = 0.1) were similar in the two groups. In protocol 2, as in protocol 1, there were no differences in the success rate (91% vs 95%; P = 1.0), ablation procedure duration (49 ± 37 vs 62 ± 55 min; P = 0.4), fluoroscopy time (46 ± 24 vs 49 ± 36 min; P = 0.8), number of applications (6.8 ± 7.0 vs 7.8 ± 12.1; P = 0.7), or number of applications associated witb coagulum formation (0.3 ± 0.6 vs 0.2 ± 0.7; P = 0.6) between the impedance and temperature monitoring groups. Conclusion: Temperature and impedance monitoring are equally effective in optimizing the results of accessory pathway ablation.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Slow Pathway Ablation. Introduction: Successful radiofrequency ablation of an accessory pathway has been demonstrated to be associated with an electrode-tissue interface temperature of approximately 60°C or an impedance change of −5 to −10 Ω. However, the temperature and impedance changes associated with ablation of AV nodal reentrant tachycardia (AVNRT) using the slow pathway approach have not been reported. Therefore, the purpose of this study was to define the temperature and impedance changes achieved during ablation of AVNRT. Methods and Results: The study included 35 consecutive patients with AVNRT undergoing radiofrequency ablation of the slow pathway with a fixed power output of 32 W, and using a catheter with a thermistor bead embedded in the distal 4-mm electrode. The procedure was successful in each patient. The steady-state electrode-tissue interface temperature during successful applications of energy was 48.5 ± 3.3°C (range 42° to 56°C), and the steady-state temperature during ineffective applications was 46.8°± 5.5°C (P = 0.03). The mean impedance change during all applications of energy was −1.4 ± 2.8 ω, and did not differ significantly during effective and ineffective applications. Coagulum formation resulted during five applications (2.7%) in two patients (5.7%). There were no recurrences during 114 ± 21 days of follow-up. Conclusions: Successful ablation of AVNRT using fixed power output is achieved at an electrode-tissue interface temperature of approximately 48°C and is associated with a drop in impedance of 1 to 2 ω. These findings suggest that slow pathway ablation requires less heating at the electrode-tissue interface than does accessory pathway or AV junction ablation.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Validation of Accessory Pathway Potentials. Four pacing maneuvers have been proposed to validate an anterograde accessory pathway potential (APP): (1) atrial pacing to induce complete block between the atrial electrogram and the APP; (2) ventricular pacing to advance the APP without altering the timing of the atrial electrogram; (3) atrial pacing to induce complete block between the APP and the ventricular electrogram; and (4) ventricular pacing to advance the ventricular electrogram without altering the timing of the APP. The purpose of this study was to assess these validation techniques by applying them to electrograms that simulated APPs but which were known to be atrial in origin. In 32 patients undergoing an electrophysiology procedure, a split atrial electrogram containing two components separated by at least 30 msec (mean 54 ± 15 msec) was recorded. Using an atrial extrastimulus tecbnique, complete block between the two components of the atrial electrogram (criterion 1) could never be induced, but complete block between the second component of the atrial electrogram and the ventricular electrogram (criterion 3) consistently was induced. Using a ventricular extrastimulus technique, the second component of the atrial electrogram consistently could be advanced by 10 to 40 msec without altering the timing of the first component (criterion 2). In addition, with ventricular pacing, the ventricular electrogram consistently was advanced without altering the timing of the two components of the atrial electrogram (criterion 4). In conclusion, among the four pacing maneuvers used to validate an anterograde APP, the only one that may be specific for an APP is the ability to induce complete block between the atrial electrogram and the APP.
    Type of Medium: Electronic Resource
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