Effect of Loss of Heart Rate Variability on T-Wave Heterogeneity and QT Variability in Heart Failure Patients: Implications in Ventricular Arrhythmogenesis
- 167 Downloads
Heart rate variability (HRV) modulates dynamics of ventricular repolarization. A diminishing value of HRV is associated with increased vulnerability to life-threatening ventricular arrhythmias, however the causal relationship is not well-defined. We evaluated if fixed-rate atrial pacing that abolishes the effect of physiological HRV, will alter ventricular repolarization wavefronts and is relevant to ventricular arrhythmogenesis. The study was performed in 16 subjects: 8 heart failure patients with spontaneous ventricular tachycardia [HFVT], and 8 subjects with structurally normal hearts (H Norm). The T-wave heterogeneity descriptors [total cosine angle between QRS and T-wave loop vectors (TCRT, negative value corresponds to large difference in the 2 loops), T-wave morphology dispersion, T-wave loop dispersion] and QT intervals were analyzed in a beat-to-beat manner on 3-min records of 12-lead surface ECG at baseline and during atrial pacing at 80 and 100 bpm. The global T-wave heterogeneity was expressed as mean values of each of the T-wave morphology descriptors and variability in QT intervals (QTV) as standard deviation of QT intervals. Baseline T-wave morphology dispersion and QTV were higher in HFVT compared to H Norm subjects (p ≤ 0.02). While group differences in T-wave morphology dispersion and T-wave loop dispersion remained unaltered with atrial pacing, TCRT tended to fall more in HFVT patients compared to H Norm subjects (interaction p value = 0.086). Atrial pacing failed to reduce QTV in both groups, however group differences were augmented (p < 0.0001). Atrial pacing and consequent loss of HRV appears to introduce unfavorable changes in ventricular repolarization in HFVT subjects. It widens the spatial relationship between wavefronts of ventricular depolarization and repolarization. This may partly explain the concerning relation between poorer HRV and the risk of ventricular arrhythmias.
KeywordsT-Wave heterogeneity QT variability Cardiomyopathy Atrial pacing Autonomic modulation
Dr. Nayyar is supported by the Robert J. Craig Electrophysiology Scholarship from the University of Adelaide. Drs. Roberts-Thomson is funded by the National Heart Foundation of Australia and the Sylvia & Charles Viertel Foundation Australia. Dr Baumert is supported by a fellowship and grant from the Australian Research Council (ARC DP 110102049).
Conflict of interests
Statement of Human Studies
All patients provided informed consent. The study was approved by the Human Research Ethics Committee of the Royal Adelaide Hospital and the University of Adelaide.
- 4.Baumert, M., V. Baier, J. Haueisen, N. Wessel, U. Meyerfeldt, A. Schirdewan, et al. Forecasting of life threatening arrhythmias using the compression entropy of heart rate. Methods Inf. Med. 43:202–206, 2004.Google Scholar
- 5.Baumert, M., A. Porta, M. A. Vos, M. Malik, J.-P. Couderc, P. Laguna, et al. QT interval variability in body surface ECG: measurement, physiological basis, and clinical value: position statement and consensus guidance endorsed by the European Heart Rhythm Association jointly with the ESC Working Group on Cardiac Cellular Electrophysiology. Europace. 18:1922–1944, 2016.Google Scholar
- 7.Boriani, G., R. Tukkie, A. S. Manolis, L. Mont, H. Purerfellner, M. Santini, et al. Atrial antitachycardia pacing and managed ventricular pacing in bradycardia patients with paroxysmal or persistent atrial tachyarrhythmias: the MINERVA randomized multicentre international trial. Eur. Heart J. 35:2352–2362, 2014.CrossRefGoogle Scholar
- 8.Chinushi, M., Y. Hosaka, T. Washizuka, H. Furushima, and Y. Aizawa. Arrhythmogenesis of T wave alternans associated with surface QRS complex alternans and the role of ventricular prematurity: observations from a canine model of LQT3 syndrome. J. Cardiovasc. Electrophysiol. 13:599–604, 2002.CrossRefGoogle Scholar
- 11.Haigney, M., W. Zareba, P. Gentlesk, R. Goldstein, M. Illovsky, S. McNitt, et al. QT interval variability and spontaneous ventricular tachycardia or fibrillation in the Multi-center Automatic Defibrillator Implantation Trial (MADIT) II patients. J. Am. Coll. Cardiol. 44:1481–1487, 2004.CrossRefGoogle Scholar
- 12.Hartikainen, J. E., M. Malik, A. Staunton, J. Poloniecki, and A. J. Camm. Distinction between arrhythmic and nonarrhythmic death after acute myocardial infarction based on heart rate variability, signal-averaged electrocardiogram, ventricular arrhythmias and left ventricular ejection fraction. J. Am. Coll. Cardiol. 28:296–304, 1996.CrossRefGoogle Scholar
- 16.Hasan, M. A., Abbott, D., and M. Baumert. Beat-to-beat spatial and temporal analysis for QRS-T morphology. In: Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) IEEE, pp. 4193–4195, 2012.Google Scholar
- 19.Hasan, M. A., Starc, V., Porta, A., Abbott, D., Baumert, M. Improved ECG pre-processing for beat-to-beat QT interval variability measurement. In: Proc Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), pp. 2563–2566, 2013.Google Scholar
- 22.Lau, C. P., N. Tachapong, C. C. Wang, J. F. Wang, H. Abe, C. W. Kong, et al. Prospective randomized study to assess the efficacy of site and rate of atrial pacing on long-term progression of atrial fibrillation in sick sinus syndrome: Septal Pacing for Atrial Fibrillation Suppression Evaluation (SAFE) Study. Circulation 128:687–693, 2013.CrossRefGoogle Scholar
- 27.Porthan, K., M. Viitasalo, L. Toivonen, A. S. Havulinna, A. Jula, J. T. Tikkanen, et al. Predictive value of electrocardiographic T-wave morphology parameters and T-wave peak to T-wave end interval for sudden cardiac death in the general population. Circ. Arrhythm Electrophysiol. 6:690–696, 2013.CrossRefGoogle Scholar
- 35.Tereshchenko, L. G., C. A. Henrikson, and R. D. Berger. Strong coherence between heart rate variability and intracardiac repolarization lability during biventricular pacing is associated with reverse electrical remodeling of the native conduction and improved outcome. J. Electrocardiol. 44:713–717, 2011.CrossRefGoogle Scholar
- 39.Zhang, Y., Z. B. Popovic, S. Bibevski, I. Fakhry, D. A. Sica, D. R. Van Wagoner, et al. Chronic vagus nerve stimulation improves autonomic control and attenuates systemic inflammation and heart failure progression in a canine high-rate pacing model. Circ. Heart Fail. 2:692–699, 2009.CrossRefGoogle Scholar