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  • Atropine  (1)
  • Key words Single-chamber cardioverter/defibrillator – dual-chamber cardioverter/defibrillator – arrhythmia detection – sensitivity – specificity  (1)
  • 1
    ISSN: 1432-1041
    Keywords: Atropine ; M2-cholinoceptors ; effect kinetics ; radioreceptor assay ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract The effects of an oral dose of atropine (0.03 mg/kg body weight) and an IM (0.02 mg/kg) dose on the heart rate and salivary flow in seven healthy adult volunteers were compared to see whether the oral dose was sufficient to inhibit vagal reflexes of the heart. Atropine concentrations in plasma were determined by an M2-selective radioreceptor assay, and the in vitro occupancy of porcine cardiac M2-cholinoceptors was measured in parallel. In ligand-binding studies, atropine has been shown to have a comparable affinity for human and porcine cardiac M2-cholinoceptors (Ki 4.0 and 5.9, respectively). Slight changes in heart rate after oral administration were not significant. After IM administration, however, the heart rate increased significantly, by a maximum of 22 beats·min−1 after 45 min. The slight increase in heart rate after the oral dose corresponded to a receptor occupancy in vitro near the lower limit of detection, whereas the significant increase in heart rate after the IM dose corresponded to a receptor occupancy of up to 47%. The maximum reduction in salivary flow was similar after the oral and IM doses (84.3 and 87.5%, respectively). The almost complete inhibition of salivary flow could be explained by the lower vagal tone in the salivary glands compared with to the heart. The difference in the effect on heart rate was probably due to lower absorption of the oral dose. Thus, an oral dose greater than 0.03 mg atropine/kilogram body weight is required to compensate for low gastrointestinal absorption and to overcome the high vagal tone of the heart.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Herzschrittmachertherapie & Elektrophysiologie 11 (2000), S. II24 
    ISSN: 1435-1544
    Keywords: Key words Single-chamber cardioverter/defibrillator – dual-chamber cardioverter/defibrillator – arrhythmia detection – sensitivity – specificity ; Schlüsselwörter Einkammer-Kardioverter/Defibrillator – Zweikammer-Kardioverter/Defibrillator – Arrhythmiedetektion – Sensitivität – Spezifität
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung: Eine falsch-positive Erkennung atrialer Tachyarrhythmien als ventrikuläre Rhythmusstörungen mit der Konsequenz elektrischer Therapien stellt auch heute noch ein bedeutsames klinisches Problem in der Therapie mit implantierbaren Kardiovertern/Defibrillatoren dar. Die methodischen Limitationen einer einkanaligen frequenzgebunden Arrhythmiedetektion wurden durch die Einführung ergänzender Arrhythmiedetektionskriterien zu überwinden versucht. Neben den seit Jahren eingeführten, ergänzenden Detektionskriterien wie “Arrhythmiestabilität” und “Arrhythmieonset” wurden zusätzlich Detektionskriterien basierend auf der Morphologieanalyse der endokardialen Elektrogramme in die klinische Therapie mit implantierbaren Defibrillatoren eingeführt. Die Einführung von Zweikammer-Defibrillator-Systemen brachte neben der wichtigen Therapieoption einer physiologischen antibradykarden Stimulation die methodischen Voraussetzungen einer verbesserten Arrhythmiedetektion durch eine simultane Zwei-Kanal-Analyse atrialer und ventrikulärer Signale. In der vorliegenden Übersicht sollen die unterschiedlichen technischen Bedingungen der Arrhythmiedetektion in Einkammer- und Zweikammer-Defibrillatoren unter Einbeziehung der Mehrzahl der klinisch eingeführten ergänzenden Detektionskriterien und Algorithmen kurz zusammenfassend beschrieben werden. Weiter wird versucht eine Übersicht über publizierte Studien und Behandlungsergebnisse zur Sensitivität und Spezifität der Arrhythmiedetektion durch Einkammer und Zweikammer Defibrillatoren darzustellen.
    Notes: Summary False-positive detection of atrial tachyarrhythmias as ventricular arrhythmias, resulting in electrical therapy, is still a major clinical problem in implantable defibrillator therapy. The introduction of enhanced arrhythmia detection parameters tried to overcome the methodical limitations of a single-channel arrhythmia classification. In addition to the enhanced detection parameters, such as “arrhythmia-stability” and “arrhythmia-onset”, introduced several years ago, new additional detection parameters, based on the analysis of intracardiac electrogram morphology, were recently introduced in clinical defibrillator therapy. The introduction of dual-chamber defibrillators provide the important option of physiological antibradycardia pacing and the technical preconditions for an improved arrhythmia classification, based on the simultaneous dual-channel analysis of atrial and ventricular signals. This manuscript will give and an overview of the technical conditions of arrhythmia detection in single and dual-chamber implantable defibrillators with respect to the majority of the clinically used enhanced arrhythmia detection parameters and detection algorithms. Additionally a summary of published studies and clinical results regarding the sensitivity and specificity of arrhythmia detection in single and dual-chamber implantable defibrillator therapy is presented.
    Type of Medium: Electronic Resource
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