Beat‐to‐Beat Heart Rate and QT Variability in Patients with Congestive Cardiac Failure: Blunted Response to Orthostatic Challenge

Desai, Nagaraj; Raghunandan, D S; Mallavarapu, Mallika; Berger, Ronald D.; Yeragani, Vikram K.

doi:10.1111/j.1542-474x.2004.94559.x

Cited by 25 publications

(11 citation statements)

References 29 publications

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“…However, this effect was absent in HF groups, strengthening the notion that sympathetic influences may only have limited influence on beat-to-beat repolarization stability in HF (8,19). As protracted sympathetic stimulation in chronic HF reduces the repolarization reserve (47), the autonomic status presumably ceases to notably affect QTV.…”

Section: Previous Studiesmentioning

confidence: 57%

Autonomic modulation of repolarization instability in patients with heart failure prone to ventricular tachycardia

Nayyar

Roberts‐Thomson

Hasan

et al. 2013

American Journal of Physiology-Heart and Circulatory Physiology

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QT variability (QTV) signifies repolarization lability, and increased QTV is a risk predictor for sudden cardiac death. The aim of the present study was to investigate the role of autonomic nervous system activity on QTV. This study was performed in 29 subjects: 10 heart failure (HF) patients with spontaneous ventricular tachycardia [HFVT(+)], 10 HF patients without spontaneous VT [HFVT(-)], and 9 subjects with structurally normal hearts (HNorm). The beat-to-beat QT interval was measured on 3-min records of surface ECGs at baseline and during interventions (atrial pacing and esmolol, isoprenaline, and atropine infusion). Variability in QT intervals was expressed as the SD of all QT intervals (SDQT). The ratio of the SDQT to SD of RR intervals (SDRR) was calculated as an index of QTV normalized to heart rate variability. There was a trend toward a higher baseline SDQT-to-SDRR ratio in the HFVT(+) group compared with the HFVT(-) and HNorm groups (P = 0.09). SDQT increased significantly in the HFVT(+) and HFVT(-) groups compared with the HNorm group during fixed-rate atrial pacing (P = 0.008). Compared with baseline, isoprenaline infusion increased SDQT in HNorm subjects (P = 0.02) but not in HF patients. SDQT remained elevated in the HFVT(+) group relative to the HNorm group despite acute β-adrenoceptor blockade with esmolol (P = 0.02). In conclusion, patients with HF and spontaneous VT have larger fluctuations in beat-to-beat QT intervals. This appears to be a genuine effect that is not solely a consequence of heart rate variation. The effect of acute autonomic nervous system modulation on QTV appears to be limited in HF patients.

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Section: Previous Studiesmentioning

confidence: 57%

Autonomic modulation of repolarization instability in patients with heart failure prone to ventricular tachycardia

Nayyar

Roberts‐Thomson

Hasan

et al. 2013

American Journal of Physiology-Heart and Circulatory Physiology

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“…9 A novel approach has been proposed to assess repolarization lability using the QT variability index (QTVi) to quantify beat-to-beat changes in the QT interval duration. 10 The QTVi is increased in CHF patients 11 and is a powerful predictor of arrhythmias and cardiac mortality. 10,12 In the present study, we evaluated QT variability in OSA patients and characterized the relationship between the severity of OSA and QT variability.…”

Section: Obstructive Sleep Apnea (Osa) Is a Common Dis-order Of Breatmentioning

confidence: 99%

Variability of QT Interval Duration in Obstructive Sleep Apnea: An Indicator of Disease Severity

Baumert

Smith

Catcheside

et al. 2008

Sleep

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Study Objective: To determine OSA-related changes in variability of QT interval duration and in heart rate variability (HRV), and to evaluate the relationship of these parameters to disease severity. Design: Retrospective analysis of diagnostic sleep records. Settings: Clinical sleep laboratory in a hospital setting. Patients: Twenty patients (12 males and 8 females) without significant comorbidities who were undergoing polysomnography were studied. Measurements and Results: Standard heart rate variability measures and QT variability (Berger algorithm) were computed over consecutive 5-minute ECG epochs throughout the night. The effect of sleep stage and the relationship between these parameters and the severity of OSA as determined by the respiratory disturbance index (RDI) were explored. Further, a linear regression model of QT variability was developed. Severity of OSA (RDI) was 49 ± 28 (range from 17-107) events/ hr. QT variability was the only ECG measure significantly correlated with RDI (both log-transformed; r = 0.6, P = 0.006). Further, QT variability was correlated with the minimum oxygen saturation (r = −0.55, P = 0.01). Sleep stage showed a significant effect on HRV, but not on QT variability. In the regression model, RDI was the strongest predictor of QT variability (R 2 increase 38%), followed by high and low frequency power of HRV (R 2 increase 10% each). Conclusion: Obstructive sleep apnea is associated with changes in QT interval variability during sleep. The variance of beat-to-beat QT intervals correlates more strongly with the severity of OSA (as determined by RDI) than standard measures of heart rate variability, and is correlated with blood oxygenation, but not sleep stage. Keywords: QT variability; heart rate variability; arousal; sleep stage; respiratory disturbance index. Citation: Baumert M; Smith J; Catcheside P; McEvoy RD; Abbott D; Sanders P; Nalivaiko E. Variability of QT interval duration in obstructive sleep apnea: an indicator of disease severity. SLEEP 2008;31(7):959-966. Disclosure StatementThis was not an industry supported study. The authors have indicated no financial conflicts of interest.

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“…QTd has been recognized as a significant prognostic, noninvasive marker of the inhomogeneity of myocardial repolarization in several diseases, especially those involving ischemic heart disease (Barr et al, 1994;Higham et al, 1995). An increase in QTd has been shown to correlate with an increased risk of arrhythmias in cardiac diseases and in congestive heart failure (Berger et al, 1997;Desai et al, 2004;Haigney et al, 2004). Consistent with those previous reports, we observed that QTd was elevated only in the 1-day ethanol withdrawal rats, who had shown the highest incidence of ventricular arrhythmic deaths in our previous study (Liu and Fujimiya, 2008, in which the same rat model was used).…”

Section: Discussionmentioning

confidence: 98%

QT Interval Dispersion and Cardiac Sympathovagal Balance Shift in Rats With Acute Ethanol Withdrawal

Shirafuji

Liu

Okamura

et al. 2010

Alcoholism Clin & Exp Res

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In rats with an abrupt termination of the chronic continuous ethanol intake, the homogeneity of myocardial repolarization impaired and correlated with the cardiac sympathovagal balance. Carvedilol pretreatment is associated with a reduction in both the QTd and LF/HF ratio, raising the possibility that the cardiac sympathovagal balance shift may be responsible for the impaired homogeneity of myocardial repolarization, and that beta-blocker pretreatment may decrease the mortality risk during alcoholic withdrawal.

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Beat‐to‐Beat Heart Rate and QT Variability in Patients with Congestive Cardiac Failure: Blunted Response to Orthostatic Challenge

Cited by 25 publications

References 29 publications

Autonomic modulation of repolarization instability in patients with heart failure prone to ventricular tachycardia

Autonomic modulation of repolarization instability in patients with heart failure prone to ventricular tachycardia

Variability of QT Interval Duration in Obstructive Sleep Apnea: An Indicator of Disease Severity

QT Interval Dispersion and Cardiac Sympathovagal Balance Shift in Rats With Acute Ethanol Withdrawal

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