Circadian variation of QT interval dispersion

Ishida, Shiro; Nakagawa, Mikiko; Fujino, Takao; Yonemochi, Hidetoshi; Saikawa, Tetsunori; Ito, Morio

doi:10.1016/s0022-0736(97)80005-2

Cited by 88 publications

(25 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the present study, the observed increases in heart rate and Nor level show a progressive increase in sympathetic activity from baseline toward the application of Ϫ15 mmHg and then Ϫ40 mmHg LBNP. The decrease in QTd associated with the increase in sympathetic tone induced by the less intense stimulus is in contradiction with several other studies, because these showed an increase in QTd with sympathetic stimulation (21,23,46) that was reduced with the use of ␤-blockers (6,28,37). Considering that the reduction of VV and adrenergic activation have opposite effects on QTd, it is possible that the reduction of VV in our study prevailed over the autonomic activation and led to a decrease in QTd.…”

Section: Discussioncontrasting

confidence: 99%

Acute reduction of ventricular volume decreases QT interval dispersion in elderly subjects with and without heart failure

Carvalho

Consolim‐Colombo

Pastore

et al. 2005

American Journal of Physiology-Heart and Circulatory Physiology

View full text Add to dashboard Cite

To evaluate the effects of acute reduction in ventricular volume (VV) on QT interval dispersion (QTd), 14 men with heart failure (HF; 74.5 Ϯ 2 yr of age) and 11 healthy male control subjects (68 Ϯ 2 yr of age) were studied. For 15 min, lower body negative pressure (LBNP) was applied at Ϫ15 and Ϫ40 mmHg to reduce venous return. At baseline and during LBNP application, QTd was measured with an 87-lead, body-surfacemapping device; chamber volumes were assessed by radioisotope ventriculography; blood pressure (BP) and heart rate (HR) were continuously monitored; and blood samples were obtained for assessment of norepinephrine (Nor) levels. At Ϫ15 mmHg, LNBP application induced a significant decrease in VV but did not change BP and HR in both groups. In addition, Nor levels increased significantly (P Յ 0.05) in the control group (from 286.7 Ϯ 31.5 to 388.8 Ϯ 41.2 pg/ml) and in HF patients (from 405.8 Ϯ 56 to 477.6 Ϯ 47 pg/ml), and QTd was significantly (P Յ 0.05) decreased in the control group (57.2 Ϯ 3.8 vs. 49.1 Ϯ 3.4 ms) and in HF patients (67.8 Ϯ 6 vs. 63.7 Ϯ 5.9 ms). No additional decreases in VV or QTd were produced by Ϫ40 mmHg LNBP, but Nor levels did increase in both groups and reach 475.5 Ϯ 34 and 586.5 Ϯ 60 pg/ml (P Ͻ 0.05) in the control and HF groups, respectively; BP did not change, but HR also increased in both groups. In conclusion, an acute LBNP-induced reduction in VV caused a decrease in the QTd of elderly men regardless of the existence of HF. Because increased sympathetic activity with more intense LBNP was not accompanied by additional changes in QTd, altered QTd may be better related to changes in VV than to autonomic nervous system activity. lower body negative pressure; cardiomyopathy; cardiac; norepinephrine; ischemic disease HEART FAILURE (HF) is a highly prevalent and important cause of morbidity and mortality in the elderly population (20). Although improvements in HF therapy have lowered mortality caused by disease progression, nearly half of the patients with HF experience sudden death (22,34). Some studies (4,7,12,14,39) have suggested that QT interval dispersion (QTd) could be associated with a higher risk of sudden death. Indeed, some investigators (16, 44) have correlated structural alterations observed in HF with increased QTd and a worse prognosis. Thus a better prognosis due to the use of drugs that attenuate ventricular remodeling [e.g., angiotensin-converting enzyme (ACE) inhibitors] seems to be associated with a more homogeneous repolarization, which leads to a decrease in QTd (3).As a result, research to detect a possible relationship between QTd behavior and factors known to influence the prognosis of HF [e.g., ventricular dysfunction, ventricular volume (VV), and neurohormonal activation] can be very useful (1, 35). Among such factors, VV is the least complex variable to study. One model that induces acute reductions in VV consists of the application of lower body negative pressure (LBNP), whereby cardiac preload is decreased because of a reduction in venous return (10). Thi...

show abstract

Section: Discussioncontrasting

confidence: 99%

Acute reduction of ventricular volume decreases QT interval dispersion in elderly subjects with and without heart failure

Carvalho

Consolim‐Colombo

Pastore

et al. 2005

American Journal of Physiology-Heart and Circulatory Physiology

View full text Add to dashboard Cite

show abstract

“…core body temperature (T core ) and brain waves), including measures of autonomic function. Notably, each of the various electrophysiological measures used to evaluate moment-by-moment ANS function – including heart rate (HR), HRV, QTc and QTc dispersion – demonstrate regular circadian rhythms (Guo & Stein, 2002; Ishida et al, 1997; Portaluppi & Hermida, 2007). …”

Section: Cb and The Ansmentioning

confidence: 99%

Bright light therapy for depression: A review of its effects on chronobiology and the autonomic nervous system

Oldham

Ciraulo

2014

Chronobiology International

View full text Add to dashboard Cite

Bright light therapy (BLT) is considered among the first-line treatments for seasonal affective disorder (SAD), yet a growing body of literature supports its use in other neuropsychiatric conditions including non-seasonal depression. Despite evidence of its antidepressant efficacy, clinical use of BLT remains highly variable internationally. In this article, we explore the autonomic effects of BLT and suggest that such effects may play a role in its antidepressant and chronotherapeutic properties. After providing a brief introduction on the clinical application of BLT, we review the chronobiological effects of BLT on depression and on the autonomic nervous system in depressed and non-depressed individuals with an emphasis on non-seasonal depression. Such a theory of autonomic modulation via BLT could serve to integrate aspects of recent work centered on alleviating allostatic load, the polyvagal theory, the neurovisceral integration model and emerging evidence on the roles of glutamate and gamma-hydroxybutyric acid (GABA).

show abstract

“…In a Holter study conducted with 17 healthy subjects, Ishida and others showed that dispersion was highest during the day (peak at approximately noon) and lowest in the evening (peak at approximately 6:00 PM). 30 The obvious implication of this finding is that the autonomic nervous system plays a role; thus, the QT interval may vary depending on sympathetic tone. In this regard, it has been shown that the adrenergic tone predominates during the day and the QT interval is prolonged during sleep, regardless of the RR interval duration.…”

Section: 2mentioning

confidence: 99%

The effects of antimalarial drugs on ventricular repolarization.

Touze¹,

Héno²,

Fourcade³

et al. 2002

The American Journal of Tropical Medicine and Hygiene

View full text Add to dashboard Cite

Abstract. Cardiotoxicity has become a major concern during treatment with antimalarial drugs. Lengthening of the QTc and severe cardiac arrhythmia have been observed, particularly after treatment with halofantrine for chloroquineresistant Plasmodium falciparum malaria. The purpose of this prospective study was to evaluate whether antimalarial agents alter dispersion of the QTc and ventricular repolarization dynamicity. Sixty patients with uncomplicated falciparum malaria were randomly allocated in four groups of 15 patients and treated with quinine, mefloquine, artemether, or halofantrine at recommended doses. Patients in treatment groups were compared with a group including 15 healthy controls with no history of malaria and/or febrile illness within the last month. QTc dispersion was measured on surface electrocardiograms. Repolarization dynamicity was analyzed from Holter recordings, which allow automatic beat-tobeat measurement of QT and RR intervals. Plasma drug concentration was determined by reversed-phase highperformance liquid chromatography. No change in QTc dispersion was observed after treatment with quinine, mefloquine, or artemether. Treatment with halofantrine was followed by a significant increase in QTc dispersion at 9 hours (P < 0.0001) and 24 hours (P < 0.01). Assessment of QT heart rate variability by QT/RR nychtohemeral regression slope demonstrated no significant difference between the artemether (mean ± SEM ‫ס‬ 0.170 ± 0.048), mefloquine (0.145 ± 0.044), and the control groups (0.172 ± 0.039). A significant decrease in the Q-eT/RR slope was observed in the quinine group compared with the control and artemether groups (0.135 ± 0.057; P < 0.04). With halofantrine, a significant increase in the QT/RR regression slope (0.289 ± 0.118) was observed (P < 0.0002). QTc interval, QT dispersion, and QT regression slope were significantly correlated with halofantrine and quinine plasma concentration. Mefloquine and artemether did not alter ventricular repolarization. Quinine induced a significant decrease in QT/RR slope of the same order of magnitude as those previously observed with quinidine. Both QTc dispersion and QT/RR slope were significantly modified by halofantrine. These repolarization changes were related to a class-III antiarrhythmic drug effect and may explain the occurrence of ventricular arrhythmia and/or sudden deaths reported after halofantrine intake.

show abstract

Circadian variation of QT interval dispersion

Cited by 88 publications

References 25 publications

Acute reduction of ventricular volume decreases QT interval dispersion in elderly subjects with and without heart failure

Acute reduction of ventricular volume decreases QT interval dispersion in elderly subjects with and without heart failure

Bright light therapy for depression: A review of its effects on chronobiology and the autonomic nervous system

The effects of antimalarial drugs on ventricular repolarization.

Contact Info

Product

Resources

About