Evaluation of Arrhythmogenic Substrate in Patients With Hypertrophic Cardiomyopathy Using Wavelet Transform Analysis

Takayama, Hideo; Yodogawa, Kenji; Katoh, Takao; Takano, Teruo

doi:10.1253/circj.70.69

Cited by 13 publications

(5 citation statements)

References 23 publications

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“…[ 2 , 7 , 10 , 14 , 26 ] Newer models have applied sophisticated signal analysis techniques but have not been validated against histological findings in an in vivo model of post-myocardial infarction. [ 17 , 18 , 27 ] To the best of our knowledge, our study demonstrated a novel quantitative approach for assessing the architectural organisation of the myocardium.…”

Section: Discussionmentioning

confidence: 97%

“…Fast Fourier Transform and wavelet analysis techniques have been described for analysis of microvolt amplitude, high frequency potentials that occur within the QRS complex of fractionated electrograms. [ 15 – 17 ] Mathematical models predict that discontinuous activation in heterogeneous myocardium gives rise to high frequency perturbations that are detectable in the unipolar electrogram frequency spectrum between 100–300 Hz. [ 18 ]…”

Section: Introductionmentioning

confidence: 99%

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Quantitative spectral assessment of intracardiac electrogram characteristics associated with post infarct fibrosis and ventricular tachycardia

et al. 2018

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BackgroundPost-myocardial infarction (MI) remodeling contributes to increased electrophysiological and structural heterogeneity and arrhythmogenesis. Utilising the post-infarct ovine model our aim was to determine unipolar electrogram frequency characteristics consequent to this remodeling and the development of Ventricular Tachycardia (VT).Methods and resultsMapping studies were performed on 14 sheep at >1 month post-MI induction. Sheep were divided into VT inducible (n = 7) and non-inducible (n = 7) groups. Multielectrode needles (n = 20) were deployed within and surrounding ventricular scar for electrophysiological assessment of electrogram amplitude and width. Spectral analysis of electrograms was undertaken using wavelet and fast fourier transformations (WFFT) to calculate root mean square (RMS) power intervals spanning 0-300Hz in 20Hz intervals. Quantitative assessment between electrophysiological and histological parameters including collagen density, and structural organization of the myocardium was performed.Increasing myocardial scar density resulted in attenuation of electrogram amplitude and RMS values. (all p<0.01). Between groups there were no differences in electrogram amplitude (p = 0.37), however WFFT analysis revealed significantly higher RMS values in the VT group (p<0.05) in association with high frequency fractional components of the electrogram. As scar density increased, greater between-group differences in RMS were observed spanning this high frequency (200-280Hz) spectrum and which were proportionally dependent on the degree of structural disorganisation of the myocardium (p<0.001) and number of extrastimuli required to induce VT (p<0.05).ConclusionHigh frequency unipolar electrogram spectral characteristics were quantitatively co-influenced by the presence of fibrosis and degree of myocardial structural dissorganisation and were associated with the propensity for development of VT.

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Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Quantitative spectral assessment of intracardiac electrogram characteristics associated with post infarct fibrosis and ventricular tachycardia

et al. 2018

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“…18 In addition, time-frequency analysis using a wavelet transform for the QRS complex of bodysurface ECG may be a clinically useful method for detecting conduction disturbances that increase VT vulnerability in hypertensive LVH. 19 In terms of determining conduction velocity, the limitation of this study is that we defined conduction velocity as the time from the pacing spike to the MAP onset between the center of LV anterior wall and apex, although recent mapping analysis can determine it accurately. 20,21 In this study, we found that conduction velocity diminished at 13W and 16W, though it was not reduced at 10W.…”

Section: Discussionmentioning

confidence: 99%

Comprehensive Analyses of Arrhythmogenic Substrates and Vulnerability to Ventricular Tachycardia in Left Ventricular Hypertrophy in Salt-Sensitive Hypertensive Rats

Kamei

Maehara

Kimura

et al. 2007

Circ J

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ypertensive left ventricular hypertrophy (LVH) is associated with an enhanced incidence of ventricular arrhythmia and an increased risk of sudden cardiac death. [1][2][3] Although in vitro studies of hypetensive LVH have proposed various electrophysiological abnormalities (ie, impulse formation 4,5 and conduction, 6-8 and repolarization abnormalities 9 ) as arrhythmogenic substrates, it remains unclear how these factors directly relate to the vulnerability to ventricular tachyarrhythmia in the in vivo whole heart. In other words, it remains poorly understood just how these electrophysiological abnormalities develop and increase the vulnerability to ventricular tachyarrhythmia with progression of LVH. The arrhythmogenic potential in hypertensive LVH may be multifactorial, but susceptibility to ventricular tachycardia (VT) induction has not been simultaneously investigated in the same LVH preparations, and therefore the relationships between various underlying arrhythmogenic mechanisms and VT attack have not been clarified. A clear understanding of this pathophysiological linkage is essential for determining the therapeutic target for prevention of fatal ventricular tachyarrhythmia. To investigate this issue, we used Dahl salt-sensitive hypertensive rats in which concentric LVH develops in a relatively short period. 10 Our preliminary study using this LVH model revealed that polymorphic VT was induced by programmed electrical stimulation, as shown by Coste et al in their clinical report. 11 Thus, the objectives of this study were first, to quantify the vulnerability of VT to programmed extrastimuli, and the changes it undergoes during the development of hypertensive LVH; second, to clarify how this vulnerability of VT relates to arrhythmogenic substrates (ie, conduction disturbances defined by a decrease in conduction velocity and an increase in the fractionation of QRS complex, and repolarization abnormalities defined by increases in the absolute refractory period and monophasic action potential (MAP) duration); and third, to examine how cellular electrophysiological remodeling relates to conduction and repolarization abnormalities of the whole heart during the progress of LVH. For these purposes, we performed programmed electrical stimulation to induce VT at 3 different observation periods in Dahl salt-sensitive (S) rats and -resistant (R) rats, and compared the vulnerability to VT with the conduction velocity and the degree of inhomogeneous conduction evaluated by wavelet analysis, 12,13 duration of MAP, 14 and absolute refractory period. In addition, myocytes were isolated from the same hearts, and patch-clamp analysis was performed for evaluation of resting membrane potential (RMP) and action potential (AP), as well as sodium (INa), calcium (ICa), and transient outward potassium currents (Ito). Background The contribution of conduction disturbances to susceptibility to ventricular tachycardia (VT) has not been directly examined in the process of left ventricular hypertrophy (LVH). Methods and ResultsDahl salt...

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“…21) Since the wavelet analysis has a time-and frequency-domain nature, time-relevant information might be preserved even during frequency analysis. 22,23) We believe that the method will be applicable for the accurate measurement of QT interval in cases of flat or inverted T wave as illustrated in Figure 1, but whether or not the method will be used is still under consideration.…”

Section: Measurement Of Qt Intervalmentioning

confidence: 99%

Clinical Background and Evaluation of Drug‐Induced Prolongation of QT Interval

Katoh

2009

Journal of Arrhythmia

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Prolongation of QT/QTc interval during medical treatment can occur not only with cardiovascular drugs but also with non-cardiovascular drugs. It may result in ventricular tachyarrhythmia, a high-risk condition which may trigger sudden cardiac death. Thus, to avoid drug-induced long QT syndrome and serious complications careful attention should be paid in the clinical setting.Moreover, in the last several years objective evaluation by strictly applying electrocardiogram (ECG) data has been strongly recommended for the development of all new drugs in discussions held at the International Conference on Harmonization (ICH). This recommendation has already been adopted in the USA and the EU and is expected to be announced shortly in our country.Not only the drugs but a variety of patient background factors may influence ECG parameters, especially the QT/QTc interval. It is necessary to introduce an appropriate study protocol that can evaluate the risk for QT/QTc prolongation related to the drug. Additionally, an adequate system to record, measure, and evaluate ECG with high objectivity must be applied to all clinical trials. (J Arrhythmia 2009; 25: 56-62)

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Evaluation of Arrhythmogenic Substrate in Patients With Hypertrophic Cardiomyopathy Using Wavelet Transform Analysis

Cited by 13 publications

References 23 publications

Quantitative spectral assessment of intracardiac electrogram characteristics associated with post infarct fibrosis and ventricular tachycardia

Quantitative spectral assessment of intracardiac electrogram characteristics associated with post infarct fibrosis and ventricular tachycardia

Comprehensive Analyses of Arrhythmogenic Substrates and Vulnerability to Ventricular Tachycardia in Left Ventricular Hypertrophy in Salt-Sensitive Hypertensive Rats

Clinical Background and Evaluation of Drug‐Induced Prolongation of QT Interval

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