Beat‐to‐Beat QT Dynamics in Healthy Subjects

Jensen, Berit T.; Larroudé, Charlotte Ellen; Rasmussen, Lars P.D.; Holstein‐Rathlou, Niels‐Henrik; Vinther, Michael; Agner, E; Kanters, Jørgen K.

doi:10.1111/j.1542-474x.2004.91510.x

Cited by 44 publications

(33 citation statements)

References 23 publications

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“…17 However, most previous studies quantified QTV based on a single ECG lead with varying electrode placements. [18][19][20][21] For practical reasons, leads with big T waves have been typically chosen, aiming for a good signal-tonoise ratio.…”

Section: Discussionmentioning

confidence: 99%

Relation between Beat‐to‐Beat QT Interval Variability and T‐Wave Amplitude in Healthy Subjects

Hasan¹,

Abbott²,

Baumert³

2012

Noninvasive Electrocardiol

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Objectives: Elevated beat-to-beat QT interval variability (QTV) has been associated with increased cardiovascular morbidity and mortality.The aim of this study was to investigate interlead differences in beat-to-beat QTV of 12-lead ECG and its relationship with the T wave amplitude.Methods: Short-term 12-lead ECGs of 72 healthy subjects (17 f, 38 ± 14 years; 55 m, 39 ± 13 years) were studied. Beat-to-beat QT intervals were extracted separately for each lead using a template matching algorithm. We calculated the standard deviation of beat-to-beat QT intervals as a marker of QTV as well as interlead correlation coefficients. In addition, we measured the median T-wave amplitude in each lead.Results: There was a significant difference in the standard deviation of beat-to-beat QT intervals between leads (minimum: lead V 3 (2.58 ± 1.36 ms), maximum: lead III (7.2 ± 6.4 ms), ANOVA: P < 0.0001). Single measure intraclass correlation coefficients of beat-to-beat QT intervals were 0.27 ± 0.18. Interlead correlation coefficients varied between 0.08 ± 0.33 for lead III and lead V 1 and 0.88 ± 0.09 for lead II and lead aVR. QTV was negatively correlated with the T-wave amplitude (r = -0.62, P < 0.0001). There was no significant affect of mean heart rate, age or gender on QT variability (ANOVA: P > 0.05).

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Section: Discussionmentioning

confidence: 99%

Relation between Beat‐to‐Beat QT Interval Variability and T‐Wave Amplitude in Healthy Subjects

Hasan¹,

Abbott²,

Baumert³

2012

Noninvasive Electrocardiol

View full text Add to dashboard Cite

show abstract

“…Systolic blood pressure amplitudes were used to calculate BPV. The wave annotation files were moved to a personal computer where ectopy and artifacts were removed using an adapted version of the Ho-Goldberger algorithm [17]. Spectral and cross-spectral analyses were performed with a Fast Fourier Transform (SAS 8.2; SAS Institute, Cary, NC).…”

Section: Hrv Bpv and Brs Measurementsmentioning

confidence: 99%

Is it possible to predict hypotension during onset of spinal anesthesia in elderly patients?

Meyhoff¹,

Haarmark²,

Kanters³

et al. 2009

Journal of Clinical Anesthesia

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“…Technically, computerized data acquisition systems for digital analyses of large volumes of high-quality digital ECG data are in their early stages of development. Only recently has it been possible to begin quantitative assessment of the sequential beat-to-beat dynamics (Jensen et al, 2004;Fossa et al, 2005;Mizumaki et al, 2005). Many issues with automated systems affecting spatial differences and T wave morphology must be overcome to improve confidence it their use without manual oversight of all beats.…”

Section: Figmentioning

confidence: 99%

QT Prolongation Modifies Dynamic Restitution and Hysteresis of the Beat-to-Beat QT-TQ Interval Relationship during Normal Sinus Rhythm under Varying States of Repolarization

Fossa¹,

Wisialowski²,

Crimin³

2005

J Pharmacol Exp Ther

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The analysis of cardiac electrical restitution (the relationship between an action potential duration and its preceding diastolic interval) has been used to predict arrhythmia liability. However, the procedure to measure restitution is invasive and disrupts normal physiological autonomic balance. Dynamic analysis of sequential beat-to-beat ECG data was used to study restitution under normal sinus rhythm and to quantify changes in temporal hysteresis with heart rate acceleration/deceleration during QT prolongation. Congenital long QT (LQT) 1 and LQT2 syndromes during sympathetic stimulation were modeled because of their association with increased risk of ventricular arrhythmia. Temporal heterogeneity and hysteresis of restitution were examined in the conscious dog under varying conditions of delayed repolarization using either the selective inhibitors of the slowly activating delayed rectifier potassium current (R)-2-(4-trifluoromethyl)-N-[2-oxo-5-phenyl-1-(2,2,2-trifluoroethyl)-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl]acetamide (L-768,673); the rapidly activating delayed rectifier potassium current (1-[2-(6-methyl-2-pyridyl)ethyl]-4-methyl-sulfonylaminobenzoyl)-piperidine (E-4031); or a combination of both at rest and during heart rate acceleration with sympathetic stimulation using isoproterenol challenges. Impaired repolarization with the combination of E-4031 and L-768,673 increased heterogeneity of restitution at rest 55 to 91%, increased hysteresis during heart rate acceleration after isoproterenol challenge by approximately 40 to 60%, and dramatically reduced the minimum TQ interval by 72% to only 28 ms. Impaired repolarization alters restitution during normal sinus rhythm and increases hysteresis/heterogeneity during heart rate acceleration following sympathetic stimulation. Thus, dynamic beat-to-beat measurements of restitution could lead to clinically applicable ECG obtained biomarkers for assessment of changes associated with arrhythmogenic risk.

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Beat‐to‐Beat QT Dynamics in Healthy Subjects

Abstract: The present study shows that reliable automatic QT measurements could be performed, encouraging further evaluation of the clinical value of QT dynamics in risk stratification of cardiac patients.

Cited by 44 publications

References 23 publications

Relation between Beat‐to‐Beat QT Interval Variability and T‐Wave Amplitude in Healthy Subjects

Relation between Beat‐to‐Beat QT Interval Variability and T‐Wave Amplitude in Healthy Subjects

Is it possible to predict hypotension during onset of spinal anesthesia in elderly patients?

QT Prolongation Modifies Dynamic Restitution and Hysteresis of the Beat-to-Beat QT-TQ Interval Relationship during Normal Sinus Rhythm under Varying States of Repolarization

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