Dynamic properties of selected repolarization descriptors

Hnatkova, Katerina; Toman, Ondřej; Šišáková, Martina; Novotný, Tomáš; Malík, Marek

doi:10.1016/j.jelectrocard.2010.06.003

Cited by 13 publications

(10 citation statements)

References 23 publications

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“…In contrast, electrocardiographic (ECG) parameters are generally less prone to acute hemodynamic changes, show a great reproducibility and are operator-independent [4–6]. However, little is known about ECG changes in DD [7–9].…”

Section: Introductionmentioning

confidence: 99%

A Novel Electrocardiographic Index for the Diagnosis of Diastolic Dysfunction

et al. 2013

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BackgroundAlthough the assessment of diastolic dysfunction (DD) is an integral part of routine cardiologic examinations, little is known about associated electrocardiographic (ECG) changes. Our aim was to investigate a potential role of ECG indices for the recognition of patients with DD.Methods and ResultsECG parameters correlating with echocardiographic findings of DD were retrospectively assessed in a derivation group of 172 individuals (83 controls with normal diastolic function, 89 patients with DD) and their diagnostic performance was tested in a validation group of 50 controls and 50 patients. The patient group with a DD Grade 1 and 2 showed longer QTc (422±24ms and 434±32ms vs. 409±25ms, p<0.0005) and shorter Tend–P and Tend–Q intervals, reflecting the electrical and mechanical diastole (240±78ms and 276±108ms vs. 373±110ms, p<0.0001; 409±85ms and 447±115ms vs. 526±119ms, p<0.0001). The PQ–interval was significantly longer in the patient group (169±28ms and 171±38ms vs. 153±22ms, p<0.005). After adjusting for possible confounders, a novel index (Tend–P/[PQxAge]) showed a high performance for the recognition of DD, stayed robust in the validation group (sensitivity 82%, specificity 93%, positive predictive value 93%, negative predictive value 82%, accuracy 88%) and proved a substantial added value when combined with the indexed left atrial volume (LAESVI, sensitivity 90%, specificity 92%, positive predictive value 95%, negative predictive value 86%, accuracy 91%).ConclusionsA novel electrocardiographic index Tend–P/(PQxAge) demonstrates a high diagnostic accuracy for the diagnosis of DD and yields a substantial added value when combined with the LAESVI.

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Section: Introductionmentioning

confidence: 99%

A Novel Electrocardiographic Index for the Diagnosis of Diastolic Dysfunction

et al. 2013

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“…In addition, the method proposed by the Malik and Hnatkova groups (Hnatkova et al. ; Malik et al. ) could have been implemented, which involves a thorough baseline evaluation of the QT‐RR relationship under a sequence of postural provocations in individual subjects at times of rapidly increasing HR.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, the study design could have been improved by conducting a pilot study with anagrelide 2.5 mg to better understand the magnitude of HR increases at this dose. In addition, the method proposed by the Malik and Hnatkova groups (Hnatkova et al 2010;Malik et al 2012) could have been implemented, which involves a thorough baseline evaluation of the QT-RR relationship under a sequence of postural provocations in individual subjects at times of rapidly increasing HR. This test provides sufficient number of ECG intervals under rapidly increasing and decreasing HRs and at a wide range of slow to fast HRs to robustly define the QT-RR relationship, including the QT-RR hysteresis, in individual subjects.…”

Section: Discussionmentioning

confidence: 99%

Effect of anagrelide on cardiac repolarization in healthy volunteers: a randomized, double‐blind, placebo‐ and positive‐controlled, thorough QT study

Troy

Parks²,

Purkayastha

et al. 2014

Pharmacology Res & Perspec

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The aim of this study was to assess the effect of low and high therapeutic doses of anagrelide (0.5 and 2.5 mg) on cardiac repolarization, measured by the QTcNi (individual correction) and QTcF (Fridericia's correction), compared with placebo and moxifloxacin 400 mg (positive control) in healthy subjects. In this randomized, double-blind, crossover trial, 60 healthy volunteers were enrolled and randomized. Anagrelide 0.5 and 2.5 mg rapidly increased mean heart rate (HR) by 7.8 and 29.1 bpm respectively. For anagrelide 2.5 mg, the maximum time-matched change (one-sided 95% upper confidence bound) in mean QTcNi and QTcF was 13.0 msec (15.7 msec) and 10.0 msec (12.7 msec), respectively, at 1 h post dose. However, time-matched changes in QTcNi and QTcF quickly decreased to <6 msec by 2 h post dose, despite high stable HR and high plasma concentrations of anagrelide and its active metabolite at these times. For anagrelide 0.5 mg, the maximum time-matched change in mean QTcNi and QTcF was 7.0 msec (9.8 msec) and 5.0 msec (8.0 msec) respectively. No new safety concerns were reported. The increase in QTc interval met the definition for a positive thorough QT/QTc study only when HR was increasing rapidly, suggesting that the increased QTc may be related to the rapidly increasing HR rather than a direct effect of anagrelide plasma concentrations. However, the direct causal relationship of anagrelide on cardiac repolarization cannot be completely excluded, and caution is advised when treating patients with known risk factors for QT interval prolongation.

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“…In our study, we used dynamic parameters of repolarization that has been previously described as suitable for the evaluation of repolarization changes, 18 especially when associated with autonomic tone modifications. 19,20 The prognostic value of these parameters was demonstrated in patients after myocardial infarction 21 and overall cardiovascular morbidity. 22 In both these studies, parameters of T-wave morphology were found to be independent predictors of arrhythmic events and survival.…”

Section: Discussionmentioning

confidence: 99%