Porta, A.* ; Girardengo, G.* ; Bari, V.* ; George, A.L. Jr.* ; Brink, P.A.* ; Goosen, A.* ; Crotti, L. ; Schwartz, P.J.*
Autonomic control of heart rate and QT interval variability influences arrhythmic risk in long QT syndrome type 1.
J. Am. Coll. Cardiol. 65, 367-374 (2015)
BACKGROUND: A puzzling feature of the long QT syndrome (LQTS) is that family members carrying the same mutation often have divergent symptoms and clinical outcomes. OBJECTIVES: This study tested the hypothesis that vagal and sympathetic control, as assessed by spectral analysis of spontaneous beat-to-beat variability of RR and QT intervals from standard 24-h electrocardiogram Holter recordings, could modulate the severity of LQTS type 1 (LQT1) in 46 members of a South-African LQT1 founder population carrying the clinically severe KCNQ1 A341V mutation. METHODS: Nonmutation carriers (NMCs) (n = 14) were compared with mutation carriers (MCs) (n = 32), 22 with and 10 without major symptoms. We assessed the effect of circadian rhythm and beta-blocker therapy over traditional time and frequency domain RR and QT variability indexes. RESULTS: The asymptomatic MCs differed significantly from the symptomatic MCs and from NMCs in less vagal control of heart rate and more reactive sympathetic modulation of the QT interval, particularly during daytime when arrhythmia risk for patients with LQT1 is greatest. CONCLUSIONS: The present data identified an additional factor contributing to the differential arrhythmic risk among patients with LQT1 carrying the same mutation. A healthy autonomic control confers a high risk, whereas patients with higher sympathetic control of the QT interval and reduced vagal control of heart rate are at lower risk. This differential "autonomic make-up," likely under genetic control, will allow refinement of risk stratification within families with LQTS, leading to more targeted management.
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Publication type
Article: Journal article
Document type
Scientific Article
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Keywords
Qt Variability ; Autonomic Nervous System ; Beta-blocker Therapy ; Cardiovascular Control ; Heart Rate Variability; Power Spectrum Analysis; Up Tilt; Stratification; Management; Severity; Genetics; Modifier; Period
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Language
english
Publication Year
2015
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2015
ISSN (print) / ISBN
0735-1097
e-ISSN
1558-3597
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Quellenangaben
Volume: 65,
Issue: 4,
Pages: 367-374
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Elsevier
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New York, NY
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Peer reviewed
POF-Topic(s)
30501 - Systemic Analysis of Genetic and Environmental Factors that Impact Health
Research field(s)
Genetics and Epidemiology
PSP Element(s)
G-500700-001
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Erfassungsdatum
2015-02-01