Document Detail

Effect of pacing cycle length and autonomic blockade on sinus node refractoriness.
MedLine Citation:
PMID:  2461648     Owner:  NLM     Status:  MEDLINE    
Sinus node (SN) refractoriness can be measured indirectly by observing the return responses after the introduction of progressively earlier atrial premature beats. The SN effective refractory period (ERP) is defined as the longest premature interval resulting in an interpolated atrial return response. In the present study, SNERP was analyzed in 71 subjects--51 control persons and 20 patients with evidence of SN dysfunction. SNERP could be measured in 40 of 51 control subjects and was shown to prolong at shorter basic pacing cycle lengths. At a basic cycle length of 600 ms, SNERP was 330 +/- 40 ms, whereas at 500 ms it was 350 +/- 50 ms (p less than 0.05). At a basic cycle length of 600 ms, SNERP was measured in 31 control subjects and 7 patients with SN dysfunction. The values of 330 +/- 40 and 520 +/- 20 ms, respectively, in these 2 groups suggested that this method can be used to differentiate patients with SN dysfunction (p less than 0.001). In 12 control subjects, SNERP was measured before and after partial autonomic blockade with propranolol and atropine. SNERP shortened from 360 +/- 40 to 320 +/- 40 ms (p less than 0.05). It shortened with atropine and prolonged with propranolol. Thus, SNERP prolongs with a shorter basic pacing cycle length and is affected by autonomic manipulation, in a fashion analogous to the atrioventricular node.
C R Kerr
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of cardiology     Volume:  62     ISSN:  0002-9149     ISO Abbreviation:  Am. J. Cardiol.     Publication Date:  1988 Dec 
Date Detail:
Created Date:  1989-01-03     Completed Date:  1989-01-03     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0207277     Medline TA:  Am J Cardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1192-6     Citation Subset:  AIM; IM    
Department of Medicine, University of British Columbia, Vancouver, Canada.
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MeSH Terms
Atropine / pharmacology
Autonomic Nervous System / physiopathology
Cardiac Complexes, Premature / physiopathology
Cardiac Pacing, Artificial / methods*
Heart Block / physiopathology*
Heart Catheterization
Middle Aged
Neural Conduction* / drug effects
Propranolol / pharmacology
Refractory Period, Electrophysiological* / drug effects
Sinoatrial Block / physiopathology*,  therapy
Sinoatrial Node / physiopathology
Time Factors
Reg. No./Substance:
51-55-8/Atropine; 525-66-6/Propranolol

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

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