Document Detail

Concealment of manifest, and exposure of concealed, ventricular parasystole produced by isoproterenol.
MedLine Citation:
PMID:  3993567     Owner:  NLM     Status:  MEDLINE    
Few studies have dealt with the effects of isoproterenol on ventricular parasystole. Intravenous isoproterenol (2 to 4 micrograms/min) was administered to 11 nonmedicated patients with ventricular parasystole. At the onset of the drip infusion, 8 patients had continuous parasystole, 2 had intermittent parasystole, and 1 patient (in whom intermittent parasystole was documented 2 to 5 days earlier) showed no manifest parasystolic activity. In all patients, whose control parasystolic cycle length varied between 960 and 2,530 ms, isoproterenol caused a decrease of the parasystolic cycle lengths ranging from 12 to 36%. Therefore, isoproterenol produced a consistent increase of the parasystolic rate. In 4 patients, parasystolic activity ceased to be manifest when the concomitantly enhanced (by isoproterenol) sinus cycle lengths became shorter than 430 ms. This phenomenon reflected a tachycardia-dependent parasystolic concealment, presumably as a result of interference in the parasystolic-ventricular junction. In every case, the arrhythmia reappeared at its initial rate upon stopping the drip infusion. In no patient did parasystolic ventricular tachycardia develop. In the patient without manifest parasystolic beats, isoproterenol unmasked the intermittent parasystole that previously had been intrinsically manifest. The latter effect reflected a true exposure, or unmasking of a latent, rate-independent concealed, parasystolic focus.(ABSTRACT TRUNCATED AT 250 WORDS)
A Castellanos; I J Mendoza; R M Luceri; C A Castillo; L Zaman; N Saoudi; R J Myerburg
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of cardiology     Volume:  55     ISSN:  0002-9149     ISO Abbreviation:  Am. J. Cardiol.     Publication Date:  1985 May 
Date Detail:
Created Date:  1985-06-03     Completed Date:  1985-06-03     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0207277     Medline TA:  Am J Cardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1344-9     Citation Subset:  AIM; IM    
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MeSH Terms
Arrhythmias, Cardiac / chemically induced,  diagnosis,  physiopathology*
Heart Ventricles / physiopathology
Infusions, Parenteral
Isoproterenol / adverse effects,  pharmacology*
Middle Aged
Myocardial Contraction / drug effects*
Sinoatrial Node / physiopathology
Systole / drug effects*
Grant Support
28130//PHS HHS
Reg. No./Substance:

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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