Influence of heart rate and inhibition of autonomic tone on the QT interval.

Ahnve, Staffan; Vallin, Hans

doi:10.1161/01.cir.65.3.435

Cited by 277 publications

(118 citation statements)

References 35 publications

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“…a p < 0.001 vs basal values; b p < 0.05 tion of the ventricle and completion of its repolarisation. QT interval is influenced by the autonomic tone [14] and represents an index of myocardial refractoriness and electrical stability; these are critical determinants of ventricular fibrillation and sudden death [15]. An association between a prolonged QT interval and sudden cardiac death has been found in various diseases including coronary artery disease and heart failure [16±17].…”

Section: Discussionmentioning

confidence: 99%

The effect of acute hyperglycaemia on QTc duration in healthy man

et al. 2000

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A prolonged heart rate-adjusted QT (corrected QT interval: QTc) is a risk factor for sudden death in patients with the long QT syndrome [1], patients with myocardial infarction [2], subjects referred for Holter monitoring [3] and healthy men and women [4±5]. A prolonged QTc interval has been reported in diabetic patients with autonomic neuropathy [6] and is associated with an increased mortality risk in nephropathic Type I (insulin-dependent) diabetic patients [7], as well as with fasting and post-challenge glucose concentrations in elderly people [8]. Moreover, an association of post-load insulin concentrations with QTc dispersion has been reported in a series of healthy subjects during oral glucose testing [9].A recent epidemiologic study in Type II (non-insulin-dependent) diabetic patients shows that the prevalence of QTc prolongation is as high as 26 % and is associated with heart disease [10].The aims of our study were to evaluate the effect of acute hyperglycaemia on haemodynamic variables, as well as QTc duration and QTc dispersion in normal subjects, and to dissect the effects of hyperglycaemia from those of hyperinsulinaemia by blocking the release of endogenous insulin with octreotide, a somatostatin analogue. AbstractAims/hypothesis. Prolongation of heart rate-adjusted QT (QTc) is associated with an increased risk of coronary heart disease and sudden death. The objective of this study was to investigate whether acute increases of plasma glucose concentrations in healthy subjects could influence QTc and QTc dispersion. Methods. Plasma glucose concentrations were quickly raised to 15 mmol/l in 20 healthy subjects (10 men/ 10 women) and maintained for 2 h. On another occasion, and in random order, all subjects underwent the same hyperglycaemic clamp as above and an infusion of the somatostatin analogue octreotide (25 mg as iv bolus followed by a 0.5 g/min infusion) to block the release of endogenous insulin. Results. Systolic and diastolic blood pressures, heart rate and plasma catecholamine concentrations showed significant increases (p < 0.05) starting after 60 min of hyperglycaemia. QTc, QTc dispersion and PR interval also showed significant increments at 120 min of the hyperglycaemic clamp. The infusion of octreotide did not influence QTc duration, QTc dispersion, PR interval and the haemodynamic effects of acute hyperglycaemia. Conclusion/interpretation. The results show that acute hyperglycaemia produces significant increments of QTc and QTc dispersion in normal subjects. In this context, endogenously released insulin during acute hyperglycaemia seems to play a minor part.

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Section: Discussionmentioning

confidence: 99%

The effect of acute hyperglycaemia on QTc duration in healthy man

et al. 2000

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“…13,14) Power spectral analysis of HRV: After the recordings were scanned by computer (SCM280, Fukuda Denshi), digitized RR intervals were transferred to a personal computer using commercially available Holter data-process-Vol 41 No 6 ing software (Version 1.033, Fukuda Denshi). Consecutive series of RR intervals obtained during the day were subjected to a "coarse-graining" spectral analysis 15) which allows elimination of the 1 / f component 16,17) from the HRV autopower spectra while leaving the harmonic component intact.…”

Section: Methodsmentioning

confidence: 99%

“…However, the response of the QT interval to pharmacological autonomic modifications is often conflicting. [4][5][6][7][8][9][10] Also, an intricate sympathovagal interaction 11) blurs the respective contribution of each limb of the autonomic nerve system to the QT interval. Thus, it is not readily predictable how the autonomic state is reflected on the QT interval in conditions without specific autonomic modifications.…”

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confidence: 99%

Is the QT Interval an Indicator of Autonomic State?

et al. 2000

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SUMMARYProlonged QT interval is suggested to indicate an increased risk of sudden cardiac death in certain clinical conditions such as diabetes mellitus. We investigated whether the individual QT interval is an indicator of an autonomic state. An ambulatory 24-hour ECG was recorded in 53 subjects from different clinical backgrounds. Power spectral components of heart rate variability (HRV) and the QT interval were regressively obtained at a heart rate of 60, 70, 80, 90, or 100 beats per minutes (bpm). Log values of the high-frequency component of HRV (HF: 0.15-0.50 Hz, a scale of cardiac parasympathetic tone) failed to show a relationship with the QT interval. In contrast, the QT interval at a heart rate of 90 bpm and 100 bpm showed a significant correlation with the log values of the low-frequency component (LF: 0.04-0.15 Hz) and the log[LF / HF], i.e., a putative scale of sympathetic tone (100 bpm: QT vs logLF: r = 0.414, p < 0.005, QT vs log[LF / HF]: r = 0.416, p < 0.002). Also, attenuated rate-dependent QT shortening was associated with greater logLF and log[LF / HF] values at a heart rate of 80, 90, or 100 bpm. These results suggest that the QT interval at a moderate heart rate (approximately 90-100 / min) and the degree of rate-dependent QT shortening are related to individual sympathetic tone. (Jpn Heart J 2000; 41: 713-721) Key words: Diabetes mellitus, Coronary artery disease, Ambulatory ECG monitoring, Heart rate variability, Sympathetic nerve, Parasympathetic nerve PPROLONGED QT intervals have been shown to be related to an increased risk of sudden cardiac death in apparently healthy subjects 1) in addition to patients with coronary artery disease (CAD)2) or diabetes mellitus (DM).3) To clarify the underlying pathogenic mechanism of these clinical observations, it appears important to understand whether the QT interval is associated with a particular cardiac autonomic state or not. However, the response of the QT interval to pharmacological autonomic modifications is often conflicting.4-10) Also, an intricate sympathovagal interaction 11) blurs the respective contribution of each limb of the autonomic nerve system to the QT interval. Thus, it is not readily predictable how the autonomic state is reflected on the QT interval in conditions without specific

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“…The QT interval is to a great extent influenced by changes in HR [56]. A variety of HR-correction formulas have been proposed in the literature to compare QT measurements at different HRs [57].…”

Section: ) Qt Adaptation To Hr Changesmentioning

confidence: 99%

Techniques for Ventricular Repolarization Instability Assessment From the ECG

2016

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Abstract-Instabilities in ventricular repolarization have been documented to be tightly linked to arrhythmia vulnerability. Translation of the information contained in the repolarization phase of the ECG into valuable clinical decision-making tools remains challenging. This work aims at providing an overview of the last advances in the proposal and quantification of ECG-derived indices that describe repolarization properties and whose alterations are related with threatening arrhythmogenic conditions. A review of the state-of-the-art is provided, spanning from the electrophysiological basis of ventricular repolarization to its characterization on the surface ECG through a set of temporal and spatial risk markers.Index Terms-Electrophysiological basis of the ECG, ECG waves, ECG intervals, repolarization instabilities, spatial and temporal ventricular repolarization dispersion, cardiac arrhythmias, biophysical modeling of the ECG, ECG signal processing, repolarization risk markers, T wave alternans, QT variability.

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Influence of heart rate and inhibition of autonomic tone on the QT interval.

Cited by 277 publications

References 35 publications

The effect of acute hyperglycaemia on QTc duration in healthy man

The effect of acute hyperglycaemia on QTc duration in healthy man

Is the QT Interval an Indicator of Autonomic State?

Techniques for Ventricular Repolarization Instability Assessment From the ECG

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