| Cardiac parasympathetic stimulation via QRS-synchronous low-energy shocks in humans. | |
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MedLine Citation:
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PMID: 9930904 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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INTRODUCTION: In patients receiving test shocks to verify lead connections at implantation, we anecdotally have observed postshock delay. The purpose of this study was to determine whether QRS-synchronous low-energy shocks delivered by implantable defibrillators result in postshock cycle length prolongation, and to determine the mechanism of this phenomenon. METHODS AND RESULTS: Twenty-five patients undergoing defibrillator testing were studied, three with epicardial patches and 22 with transvenous leads. Each patient received QRS-synchronous shocks of 0.2, 0.4, 0.6, and 2.0 J in random order. Patients were further randomized to receive either saline or 2.0 mg atropine intravenously, and then given a second sequence of shocks. At baseline, the postshock cycle length (1,035+/-245 msec) was significantly longer than the preshock cycle length (968+/-177 msec, P = 0.01). In patients with a coronary sinus (CS) or superior vena cava (SVC) lead, the mean prolongation was 91+/-160 msec, compared with 12+/-106 msec for patients without such a lead (P < 0.0001). All energy levels resulted in significant postshock prolongation compared with preshock cycle lengths (P < 0.05). Postshock prolongation before atropine was 76+/-162 msec, compared with -13+/-52 msec afterward (P < 0.00001). Biphasic shocks resulted in greater postshock prolongation than monophasic shocks of equal energy. CONCLUSION: Low-energy shocks delivered during the QRS complex cause postshock cycle length prolongation in man. This effect required the presence of a CS or SVC lead. Atropine inhibited this effect, suggesting the phenomenon was mediated by direct cardiac parasympathetic nerve stimulation by the intracardiac shock. |
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Authors:
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P A Friedman; M R Hill; M S Stanton |
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Publication Detail:
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Type: Clinical Trial; Comparative Study; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of cardiovascular electrophysiology Volume: 10 ISSN: 1045-3873 ISO Abbreviation: J. Cardiovasc. Electrophysiol. Publication Date: 1999 Jan |
Date Detail:
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Created Date: 1999-03-30 Completed Date: 1999-03-30 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 9010756 Medline TA: J Cardiovasc Electrophysiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 10-6 Citation Subset: IM |
Affiliation:
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Division of Cardiovascular Disease, Mayo Clinic, Rochester, Minnesota 55905, USA. pfriedman@mayo.edu |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Aged Aged, 80 and over Defibrillators, Implantable Diagnosis, Differential Electric Countershock* Electrocardiography* Follow-Up Studies Heart / innervation* Humans Middle Aged Parasympathetic Nervous System / physiopathology* Recurrence Tachycardia, Supraventricular / diagnosis, physiopathology, therapy* Tachycardia, Ventricular / diagnosis, physiopathology, therapy* Treatment Outcome |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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