Document Detail

Effect of adrenergic stimulation on action potential duration restitution in humans.
MedLine Citation:
PMID:  12538429     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Enhanced sympathetic activity facilitates complex ventricular arrhythmias and fibrillation. The restitution properties of action potential duration (APD) are important determinants of electrical stability in the myocardium. Steepening of the slope of APD restitution has been shown to promote wave break and ventricular fibrillation. The effect of adrenergic stimulation on APD restitution in humans is unknown. METHODS AND RESULTS: Monophasic action potentials were recorded from the right ventricular septum in 18 patients. Standard APD restitution curves were constructed at 3 basic drive cycle lengths (CLs) of 600, 500, and 400 ms under resting conditions and during infusion of isoprenaline (15 patients) or adrenaline (3 patients). The maximum slope of the restitution curves was measured by piecewise linear regression segments of sequential 40-ms ranges of diastolic intervals in steps of 10 ms. Under control conditions, the maximum slope was steeper at longer basic CLs; eg, mean values for the maximum slope were 1.053+/-0.092 at CL 600 ms and 0.711+/-0.049 at CL 400 ms (+/-SEM). Isoprenaline increased the steepness of the maximum slope of APD restitution, eg, from a maximum slope of 0.923+/-0.058 to a maximum slope of 1.202+/-0.121 at CL 500 ms. The effect of isoprenaline was greater at the shorter basic CLs. A similar overall effect was observed with adrenaline. CONCLUSIONS: The adrenergic agonists isoprenaline and adrenaline increased the steepness of the slope of the APD restitution curve in humans over a wide range of diastolic intervals. These results may relate to the known effects of adrenergic stimulation in facilitating ventricular fibrillation.
Peter Taggart; Peter Sutton; Zaid Chalabi; Mark R Boyett; Ron Simon; Donna Elliott; Jaswinder S Gill
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Publication Detail:
Type:  Clinical Trial; Journal Article    
Journal Detail:
Title:  Circulation     Volume:  107     ISSN:  1524-4539     ISO Abbreviation:  Circulation     Publication Date:  2003 Jan 
Date Detail:
Created Date:  2003-01-22     Completed Date:  2003-01-28     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  United States    
Other Details:
Languages:  eng     Pagination:  285-9     Citation Subset:  AIM; IM    
The Hatter Institute, Department of Cardiology, University College London HospitalsLondon, WC1E 6DB.
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MeSH Terms
Action Potentials / drug effects,  physiology*
Adrenergic alpha-Agonists / pharmacology*
Adrenergic beta-Agonists / pharmacology*
Diastole / physiology
Electrophysiologic Techniques, Cardiac*
Epinephrine / pharmacology
Heart Ventricles / drug effects
Isoproterenol / pharmacology
Middle Aged
Signal Processing, Computer-Assisted
Ventricular Function*
Reg. No./Substance:
0/Adrenergic alpha-Agonists; 0/Adrenergic beta-Agonists; 51-43-4/Epinephrine; 7683-59-2/Isoproterenol

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

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