Diurnal variation of the QT interval--influence of the autonomic nervous system.

Bexton, R. S.; Vallin, Hans; Camm, A. John

doi:10.1136/hrt.55.3.253

Cited by 220 publications

(87 citation statements)

References 23 publications

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“…When sequential tracings from patients recorded at different times of day and at different locations are compared, it is important to recognize that the time of day can influence the QT interval, 57,58 that differences may exist between the different recording systems and between the programs used for QT measurement, and that different formulas for QT-rate adjustment may have been used. Moreover, there is a significant interreader variability in the measurement of QT interval.…”

Section: Correction For Qrs Durationmentioning

confidence: 99%

AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram

Rautaharju¹,

Surawicz²,

Gettes³

2009

Circulation

391

222

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Section: Correction For Qrs Durationmentioning

confidence: 99%

AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram

Rautaharju¹,

Surawicz²,

Gettes³

2009

Circulation

391

222

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“…fatty acids; glucose; glycogen; triglyceride CIRCADIAN RHYTHMS IN CARDIOVASCULAR PHYSIOLOGY and pathophysiology are well established. Heart rate, blood pressure, cardiac output, platelet aggregability, myocardial infarction, arrhythmias, and sudden cardiac death all exhibit marked circadian rhythmicities in both humans and animal models (3,7,12,18,23,33). To date, these observations have been attributed primarily to diurnal variations in multiple extracellular stimuli (i.e., neurohumoral factors) such as autonomic and sympathetic activity (23,24,32).…”

mentioning

confidence: 99%

Circadian rhythms in myocardial metabolism and contractile function: influence of workload and oleate

Durgan¹,

Moore²,

Ha³

et al. 2007

American Journal of Physiology-Heart and Circulatory Physiology

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ME. Circadian rhythms in myocardial metabolism and contractile function: influence of workload and oleate. Am J Physiol Heart Circ Physiol 293: H2385-H2393, 2007. First published July 6, 2007; doi:10.1152/ajpheart.01361.2006.-Multiple extracardiac stimuli, such as workload and circulating nutrients (e.g., fatty acids), known to influence myocardial metabolism and contractile function exhibit marked circadian rhythms. The aim of the present study was to investigate whether the rat heart exhibits circadian rhythms in its responsiveness to changes in workload and/or fatty acid (oleate) availability. Thus, hearts were isolated from male Wistar rats (housed during a 12:12-h light-dark cycle: lights on at 9 AM) at 9 AM, 3 PM, 9 PM, and 3 AM and perfused in the working mode ex vivo with 5 mM glucose plus either 0.4 or 0.8 mM oleate. Following 20-min perfusion at normal workload (i.e., 100 cm H 2O afterload), hearts were challenged with increased workload (140 cm H 2O afterload plus 1 M epinephrine). In the presence of 0.4 mM oleate, myocardial metabolism exhibited a marked circadian rhythm, with decreased rates of glucose oxidation, increased rates of lactate release, decreased glycogenolysis capacity, and increased channeling of oleate into nonoxidative pathways during the light phase. Rat hearts also exhibited a modest circadian rhythm in responsiveness to the workload challenge when perfused in the presence of 0.4 mM oleate, with increased myocardial oxygen consumption at the dark-to-light phase transition. However, rat hearts perfused in the presence of 0.8 mM oleate exhibited a markedly blunted contractile function response to the workload challenge during the light phase. In conclusion, these studies expose marked circadian rhythmicities in myocardial oxidative and nonoxidative metabolism as well as responsiveness of the rat heart to changes in workload and fatty acid availability. fatty acids; glucose; glycogen; triglyceride CIRCADIAN RHYTHMS IN CARDIOVASCULAR PHYSIOLOGY and pathophysiology are well established. Heart rate, blood pressure, cardiac output, platelet aggregability, myocardial infarction, arrhythmias, and sudden cardiac death all exhibit marked circadian rhythmicities in both humans and animal models (3,7,12,18,23,33). To date, these observations have been attributed primarily to diurnal variations in multiple extracellular stimuli (i.e., neurohumoral factors) such as autonomic and sympathetic activity (23,24,32). However, it is becoming increasingly clear that the intrinsic properties of cardiovascular components change over the course of the day, suggesting that oscillations in responsiveness to extracellular stimuli may contribute toward circadian rhythmicities in cardiovascular events (36, 37).Myocardial metabolism and contractile function are inextricably interlinked. For example, increased energy demand during periods of elevated workload is balanced by increased oxidative and nonoxidative metabolism (17). An inability of the heart to maintain adequate ATP supply will in turn adversely affect...

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“…As there is strong diurnal variation in sympathetic activity, which may impact on arrhythmia generation in disease conditions, 17,18 we also looked at the impact of ␤-adrenergic stimulation on contraction and L-type Ca 2ϩ current density and its impact in arrhythmia generation.…”

mentioning

confidence: 99%

Inotropic Response of Cardiac Ventricular Myocytes to β-Adrenergic Stimulation With Isoproterenol Exhibits Diurnal Variation

Collins

Rodrigo

2010

Circulation Research

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Diurnal variation of the QT interval--influence of the autonomic nervous system.

Cited by 220 publications

References 23 publications

AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram

AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram

Circadian rhythms in myocardial metabolism and contractile function: influence of workload and oleate

Inotropic Response of Cardiac Ventricular Myocytes to β-Adrenergic Stimulation With Isoproterenol Exhibits Diurnal Variation

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