Temporal dispersion of the QT interval and its relation to heart rate variability

Kostis, William J.; Belina, J.

doi:10.1109/iembs.1995.575049

Cited by 2 publications

(2 citation statements)

References 4 publications

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“…39 Kostis and Belina found that QTd offers valuable information in combination with heart rate variability. 40 Abbreviations as in Table II. dition to ejection fraction and late potentials gives independent information concerning ventricular arrhythmia induction during electrophysiologic studies. 41…”

Section: Study Limitationsmentioning

confidence: 99%

QT‐interval dispersion in acute myocardial infarction is only shortened by thrombolysis in myocardial infarction grade 2/3 reperfusion

Nikiforos

Hatzisavvas

Pavlides

et al. 2003

Clinical Cardiology

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SummaryBackground: Increased QT interval dispersion (QTd) has been found in patients with acute myocardial infarction (AMI). In previous studies this has been shown to decrease with thrombolysis.Hypothesis: The aim of this study was to compare the effects of reperfusion by primary percutaneous transluminal coronary angioplasty (PTCA) and by thrombolysis on QTd and correlate these results with the degree of reperfusion.Methods: We studied 60 patients with a first AMI. The study cohort included 40 consecutive patients who had received thrombolysis (streptokinase or rt-PA); 20 additional consecutive patients with successful primary PTCA, all with preselected Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow by predefined selection criteria (12 stents); and 20 controls. A 12-lead ECG for QTd calculation was recorded before thrombolysis or PTCA and immediately after the procedure. All values were corrected according to Bazett's formula (QTcd). QTd and QTcd values before and after each procedure in three groups and the respective percent changes of ∆QTd and ∆QTcd were compared separately.Results: QTd and QTcd were significantly increased before thrombolysis/PTCA versus normals. An angiogram performed after thrombolysis showed adequate reperfusion (TIMI grade

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Section: Study Limitationsmentioning

confidence: 99%

QT‐interval dispersion in acute myocardial infarction is only shortened by thrombolysis in myocardial infarction grade 2/3 reperfusion

Nikiforos

Hatzisavvas

Pavlides

et al. 2003

Clinical Cardiology

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show abstract

“…These recordings were analyzed by using previously developed and tested algorithms. 15,16 Recordings sampled at 128 Hz were converted by using an Oxford-Medilog Optima system to generate two-channel binary data that were then transferred to a Hewlett-Packard HP-UX cluster for analysis. Data were corrected for variation in tape recorder and playback speed by the use of a simultaneously recorded clock signal.…”

Section: Anddquo;mentioning

confidence: 99%

Differences in Beat-to-Beat Variability of the QT Interval Between Day and Night

Kostis

Belina

2000

Angiology

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The objective of this study was to evaluate the beat-to-beat variability of the QT interval during the day and night. A new algorithm was used to detect the onset of the QRS, the apex of the T wave, and end of the T in ambulatory electrocardiographic recordings. Beat-to-beat variability of QT, QaT, and QTc during the day and night was studied in the time, frequency, and chaotic domains. Participants were adults without clinical evidence of heart disease. Although the QT duration was higher (p = 0.0001) at night, the beat-to-beat variability of this interval was lower: in the time domain (decreased standard deviation, p = 0.0005), in the frequency domain (decreased low-frequency power of the spectra, p = 0.004), and the chaotic domain (tighter clustering of the points in the Poincaré plots). The high-frequency to low-frequency ratio of the power spectra of the QT (and the RR) was higher (p = 0.03) at night. Beat-to-beat QT variability in the time, frequency, and chaotic domains is decreased at night with shift of the QT modulation to higher frequencies corresponding to respiration and representing vagal preponderance. The techniques presented here and the findings in normal subjects may be useful in evaluating the risk for arrhythmic events in patients with heart disease.

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Temporal dispersion of the QT interval and its relation to heart rate variability

Cited by 2 publications

References 4 publications

QT‐interval dispersion in acute myocardial infarction is only shortened by thrombolysis in myocardial infarction grade 2/3 reperfusion

QT‐interval dispersion in acute myocardial infarction is only shortened by thrombolysis in myocardial infarction grade 2/3 reperfusion

Differences in Beat-to-Beat Variability of the QT Interval Between Day and Night

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