Document Detail

Genetic susceptibility to acquired long QT syndrome: pharmacologic challenge in first-degree relatives.
MedLine Citation:
PMID:  15851285     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: The purpose of this study was to test for a genetic component to risk for acquired long QT syndrome (LQTS). BACKGROUND: Many drugs prolong the QT interval, and some patients develop excessive QT prolongation and occasionally torsades de pointes-the acquired LQTS. Similarities between the acquired and congenital forms of the long QT syndrome suggest genetic factors modulate susceptibility. METHODS: Intravenous quinidine was administered to 14 relatives of patients who safely tolerated chronic therapy with a QT-prolonging drug (control relatives) and 12 relatives of patients who developed acquired LQTS, and ECG intervals between groups were compared. RESULTS: Baseline QT and heart-rate corrected QT (QTc) were similar (QT/QTc: 394 +/- 28/410 +/- 20 ms vs 395 +/- 24/418 +/- 20 ms; control vs acquired LQTS) and prolonged equally in the two groups. The interval from the peak to the end of the T wave, an index of transmural dispersion of repolarization, prolonged significantly with quinidine in acquired LQTS relatives (63 +/- 17 to 83 +/- 18 ms, P = .017) but not in control relatives (66 +/- 19 to 71 +/- 18 ms, P = 0.648). In addition, the baseline peak to end of the T wave as a fraction of the QT interval was similar in both groups but was longer in acquired LQTS relatives after quinidine (16.3 +/- 3.5% and 19.5 +/- 3.9% in control and acquired LQTS relatives, respectively, P = .042). CONCLUSIONS: First-degree relatives of patients with acquired long QT syndrome have greater drug-induced prolongation of terminal repolarization compared to control relatives, supporting a genetic predisposition to acquired long QT syndrome.
Prince J Kannankeril; Dan M Roden; Kris J Norris; S Patrick Whalen; Alfred L George; Katherine T Murray
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Heart rhythm : the official journal of the Heart Rhythm Society     Volume:  2     ISSN:  1547-5271     ISO Abbreviation:  Heart Rhythm     Publication Date:  2005 Feb 
Date Detail:
Created Date:  2005-04-26     Completed Date:  2005-06-08     Revised Date:  2009-10-27    
Medline Journal Info:
Nlm Unique ID:  101200317     Medline TA:  Heart Rhythm     Country:  United States    
Other Details:
Languages:  eng     Pagination:  134-40     Citation Subset:  IM    
Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA.
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MeSH Terms
Anti-Arrhythmia Agents / diagnostic use*
Genetic Predisposition to Disease / genetics*
Long QT Syndrome / genetics*
Middle Aged
Quinidine / diagnostic use*
Grant Support
Reg. No./Substance:
0/Anti-Arrhythmia Agents; 56-54-2/Quinidine

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

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