Document Detail


Normalization of acquired QT prolongation in humans by intravenous potassium.
MedLine Citation:
PMID:  9337183     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: QT interval prolongation and dispersion have been implicated in serious arrhythmias in congestive heart failure (CHF) and the congenital and drug-induced long-QT syndromes (LQTS). In a subset of the congenital LQTS, infusion of potassium can correct QT abnormalities, consistent with in vitro increases in outward currents such as I(Kr) or I(Kl) when extracellular potassium concentration ([K+]o) is increased. Furthermore, increasing [K+]o decreases the potency of I(Kr)-blocking drugs in vitro. The purpose of this study was to test the hypothesis that increasing [K+]o corrects QT abnormalities in CHF and in subjects treated with quinidine. METHODS AND RESULTS: KCl (maximum, 40 mEq) was infused into (1) 12 healthy subjects treated with quinidine sulfate (5 doses of 300 mg/5 h) or placebo and (2) 8 CHF patients and age-matched normal control subjects. Mean [K+] increased from 4 to 4.2 mEq/L to 4.7 to 5.2 mEq/L. Potassium infusion significantly reversed QTUc prolongation, especially in the precordial leads (quinidine, 590+/-79 to 479+/-35 [+/-SD] ms(1/2), P<.001; CHF, 521+/-110 to 431+/-47 ms(1/2), P<.05). There was no effect in either control group. Similarly, potassium decreased QTUc dispersion (quinidine, 210+/-62 to 130+/-75 ms(1/2), P<.01; CHF, 132+/-68 to 84+/-35 ms(1/2), P=.07) and was without effect in the control subjects. QT morphological abnormalities, including U waves and bifid T waves, were reversed by potassium. CONCLUSIONS: Potentially arrhythmogenic QT abnormalities during quinidine treatment and in CHF can be nearly normalized by modest elevation of serum potassium.
Authors:
A M Choy; C C Lang; D M Chomsky; G H Rayos; J R Wilson; D M Roden
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Publication Detail:
Type:  Clinical Trial; Controlled Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Circulation     Volume:  96     ISSN:  0009-7322     ISO Abbreviation:  Circulation     Publication Date:  1997 Oct 
Date Detail:
Created Date:  1997-10-31     Completed Date:  1997-10-31     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2149-54     Citation Subset:  AIM; IM    
Affiliation:
Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tenn 37232-6602, USA.
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MeSH Terms
Descriptor/Qualifier:
Adult
Electrocardiography / drug effects*
Female
Heart Failure / physiopathology*
Humans
Infusions, Intravenous
Male
Potassium / administration & dosage,  blood,  pharmacology*
Potassium Chloride / administration & dosage,  pharmacology
Quinidine / pharmacology*
Reference Values
Grant Support
ID/Acronym/Agency:
GM-31304/GM/NIGMS NIH HHS; RR-00095/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
56-54-2/Quinidine; 7440-09-7/Potassium; 7447-40-7/Potassium Chloride

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


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