Physiologic relation between cardiac cycle and QT duration in healthy volunteers

Lecocq, B.; Lecocq, V.; Jaillon, Patrice

doi:10.1016/0002-9149(89)90425-6

Cited by 78 publications

(41 citation statements)

References 23 publications

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“…90, and 100 bpm, 3) logHF values showed no relationship with the QT interval or ∆QT. Earlier studies associated with autonomic regulation of the QT interval: Although a number of earlier studies using autonomic agonists and antagonists have suggested predominant parasympathetic modulation of the QT interval, [4][5][6] others have emphasized the sympathetic regulation of this interval. [7][8][9] Browne, et al reported a shortening of the corrected QT interval during treatment with propranolol.…”

Section: Discussionmentioning

confidence: 99%

“…10) Conflicting reports also exist where, with heart rate kept constant by atrial pacing, isoproterenol infusion reduced QT interval in one report, 12) but in another report, isoproterenol showed a marked prolongation of the QT interval even if the heart rate is taken into consideration. 5,9) Consequently, the difference in sympathovagal regulation between the sinus node and ventricular repolarization, 22) variation in the parasympathetic modification of the sympathetic tone at different heart rates, 11,23) and the rate-dependent feature of the QT interval contribute to the difficulties in defining the autonomic background of the prolonged QT interval.…”

Section: Discussionmentioning

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%

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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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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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Is the QT Interval an Indicator of Autonomic State?

et al. 2000

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“…An increase in heart rate during isoflurane anaesthesia has been established in mammals and is probably due to a drop in blood pressure caused by the anaesthetic (Murray et al, 1987). In mammals an increase in heart rate is normally accompanied by shortening of the QT-interval (Lecocq et al, 1989). The increased heart rate in the anaesthetized parrots in combination with a prolongation of the QT-interval is remarkable and could be due to recording the ECG soon after mask induction.…”

Section: Discussionmentioning

confidence: 99%

Electrocardiogram of the African grey (psittacus erithacus) and Amazon (Amazonaspp.) parrot

1992

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SUMMARYElectrocardiographic reference values and configurations were established in apparently healthy African grey (Psittacus erithacus; n=45) and Amazon (Amazona spp.; n = 37) parrots, using standard limb leads. In 31 of the African grey parrots and 32 of the Amazon parrots electrocardiograms were made during isoflurane-anaesthesia. Significant differences between anaesthetized and unanaesthetized birds were found only for the median heart rate and QTinterval (P<0.05). Significant differences between the two genera were found for the duration of the P-and T-waves, the voltage of the T-wave and for the mean electrical axis.Sinus arrhythmias and ventricular premature beats were present in 5 to 10% of the tracings.

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“…Foremost among all these is the rate-dependent nature of the QT interval. In most species examined, it is well-established that the duration of the QT interval is inversely related to the heart rate (HR) of the subject under examination (7,40). Thus, any changes in the raw QT interval must be carefully interpreted and reported with caution.…”

Section: Qt Interval and In Vivo Methodologymentioning

confidence: 99%

The Dog's Role in the Preclinical Assessment of QT Interval Prolongation

Gralinski¹

2003

Toxicol Pathol

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During the development of a new therapeutic, few pharmacodyamic outcomes currently receive as much scrutiny as the effect of a potential medication on the electrocardiographic QT interval. The recent withdrawal from marketing of several drugs due to potential drug-related cardiac arrhythmias have greatly increased concern about drug-related changes on the QT interval. In order to reduce the incidence of these idiosyncratic episodes, regulatory agencies have suggested that sponsors use more rigorous methodology during the safety evaluation of new pharmaceuticals. Along with enhanced electrocardiographic assessments during clinical trials, advanced preclinical examinations of effect on QT interval and ventricular repolarization have become de rigueur. In this arena, the beagle dog is the preclinical species often associated with the most reliable predictivity for human safety assessment. To this end, canine models of cardiovascular safety assessment are discussed along with the relevance of these assays to human electrocardiography.

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Physiologic relation between cardiac cycle and QT duration in healthy volunteers

Cited by 78 publications

References 23 publications

Is the QT Interval an Indicator of Autonomic State?

Is the QT Interval an Indicator of Autonomic State?

Electrocardiogram of the African grey (psittacus erithacus) and Amazon (Amazonaspp.) parrot

The Dog's Role in the Preclinical Assessment of QT Interval Prolongation

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