O eletrocardiograma de alta resolução no domínio da freqüência. Utilização de técnicas estatísticas de correlação espectral para identificação de pacientes com taquicardia ventricular monomórfica sustentada

Barbosa, Eduardo Corrêa; Benchimol-Barbosa, Paulo Roberto; Ginefra, P; Fo, Francisco Manes Albanesi

doi:10.1590/s0066-782x1998001000007

Cited by 9 publications

(8 citation statements)

References 16 publications

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“…The correlation between ventricular late potentials and sustained monomorphic ventricular tachycardia has been widely discussed in the literature [2][3]13,18 . One week after transmural myocardial infarction, approximately 30% to 60% of patients have ventricular late potentials on signal-averaged electrocardiography.…”

Section: Discussionmentioning

confidence: 99%

Analysis of the Prevalence of Ventricular Late Potentials in the Late Phase of Myocardial Infarction Based on the Site of Infarction

Paulo

Benchimol-Barbosa

Sousa

et al. 2002

Arq. Bras. Cardiol.

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Objective -The initial site of myocardial infarction (MI) may influence the prevalence of ventricular late potentials (VLP), high-frequency signals, due to the time course of ventricular activation. The prevalence of VLP in a period of more than 2 years after acute MI was assessed focusing on the initially injured wall . Methods - [1][2][3] . Due to the low velocity of conduction, these potentials exceed the duration of ventricular activation and are detected in the ST-segment. The use of statistical techniques, in which 2 to 3 hundred sequential QRS complexes detected on the body surface are independently coherent-averaged, allows amplification and identification of these signals because of the reduction in the intensity of the instrumentation noises 4-7 .The identification of ventricular late potentials in patients with a transmural myocardial infarction is of major interest 3,[8][9][10] . The myocardial remodeling process that follows transmural myocardial infarction is characterized by fibrosis, redistribution of fibers in the injured region, and residual metabolic alterations not only plays a major role in segmentary myocardial function but also provides a favorable environment for the development of reentry circuits 11 .Considering these markers, preliminary studies suggest that transmural myocardial infarctions involving the inferiorinferodorsal wall have a higher prevalence of ventricular late potentials than those involving the anterior-anteroseptal wall. These findings are based on differences related to the start of electrical activation in the affected regions 12,13 . However, studies relating the prevalence of ventricular late potentials after transmural myocardial infarction with the affected wall show some conflicting results. Some studies have focused attention on the occurrence of ventricular late potentials in the first 12 months after transmural myocardial infarction when the myocardial remodeling process is still underway 14 . Data on the prevalence of ventricular late potentials in a late phase (>2 years) of transmural myocardial infarction are very scarce. In this phase, the prevalence of ventricular late potentials reflects not only the natural

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Section: Discussionmentioning

confidence: 99%

Analysis of the Prevalence of Ventricular Late Potentials in the Late Phase of Myocardial Infarction Based on the Site of Infarction

Paulo

Benchimol-Barbosa

Sousa

et al. 2002

Arq. Bras. Cardiol.

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“…The mark of the arrhythmogenic abnormality is theorized to be the frequent and abrupt change in the direction of the wave front activation, crossing areas of abnormal conduction, resulting in the presence of spectral turbulence 13 .…”

Section: Discussionmentioning

confidence: 99%

“…Based on P-wave spectral mapping, some authors investigated spectral turbulence as a marker of intraatrial conduction disorders [13][14][15] . In this context, P-wave signalaveraged electrocardiography proved to be a noninvasive, low-cost, easily performed and reproducible method; therefore, it has been widely used in the evaluation and stratification of the risk of atrial fibrillation [16][17][18][19][20][21][22][23][24][25][26][27] .…”

Section: Discussionmentioning

confidence: 99%

Atrial activation during sinus rhythm in patients with rheumatic and non-rheumatic paroxysmal atrial fibrillation. Frequency-domain analysis using signal-averaged electrocardiography

Dantas¹,

Barbosa²,

Benchimol-Barbosa³

et al. 2001

Arq. Bras. Cardiol.

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Objective -Using P-wave signal-averaged electrocardiography, we assessed the patterns of atrial electrical activation in patients with idiopathic atrial fibrillation as compared with patterns in patients with atrial fibrillation associated with structural heart disease. Atrial fibrillation is the most common sustained arrhythmia diagnosed in clinical practice [1][2][3][4] . In the general population, its prevalence increases with age: it is lower than 1% in the age bracket from 40 to 65 years, ranges from 2% to 5% in the age bracket from 65 to 74 years, and is higher than 5% above the age of 75 years. No difference in incidence has been observed between the sexes 1 . The increase in prevalence and incidence of atrial fibrillation with age is mainly associated with coexisting cardiac diseases. However, an independent effect of direct ageing on the atrial tissue cannot be excluded 5 . Methods -Eighty patients with recurrent paroxysmalA history of congestive heart failure, rheumatic valvar disease, left ventricular hypertrophy, and left atrial enlargement are independent risk factors associated with the genesis of atrial fibrillation. The presence of this arrhythmia in structurally normal hearts, although infrequent, may be detected in clinical practice. The triggering and maintenance factors of idiopathic atrial fibrillation are not very well defined. However, a significant number of patients with the paroxysmal or persistent form of atrial fibrillation, even though without evidence of anatomical cardiac alterations, evolve towards chronic atrial fibrillation. Such patients include those with structural heart disease despite the use of antiarrhythmic drugs. The objective of our study was to identify the electrophysiological behavior of atrial activation in patients with paroxysmal or persistent atrial fibrillation, through the use of P-wave signal-averaged electrocardiography for frequency-domain analysis. MethodsIn a cross-sectional study, we analyzed 80 patients who were being followed up in the outpatient cardiac arrhythmia care unit of the Hospital Universitário Pedro Ernesto. These patients had a history of at least 2 episodes of paroxysmal or persistent atrial fibrillation confirmed on electrocardiography in the last year, and they had not used any antiarrhythmic drug for at least 5 half-lives of each drug in

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“…The highest TDA value corresponding to a spectral turbulence variables normality threshold arrangement and a given STFT configuration set defined the optimal set variables capable of distinguishing between Control and SMVT groups. As a convention, the presence of high spectral turbulence is considered when at least two out of four variables are outside respective normality threshold, according to Kelen et al [3] and Barbosa et al [7]. In the present study, all four different diagnostic criteria were tested: one, two, three or four out of four variables.…”

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confidence: 99%

“…In 1998, Barbosa et al [7], starting from configurations recommended by Kellen et al [3] updated threshold values for spectral turbulence variables in subjects with monomorphic ventricular tachycardia (MSC ≤ 0.95, SDEC ≥ 0.06, MET ≥ 78 and SDET ≥ 31). In that study and population, it was possible to derive the TDA in 72.2%.…”

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confidence: 99%

The effect of configuration parameters of time-frequency maps in the detection of intra-QRS electrical transients of the signal-averaged electrocardiogram: Impact in clinical diagnostic performance

Benchimol-Barbosa

Nasario-Junior

Nadal

2010

International Journal of Cardiology

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Time-frequency maps of signal-averaged electrocardiogram based on a short time Fourier transform (STFT) technique analysis was employed to assess the presence of high frequency electrical transients (turbulence) and arrhythmia risk assessment. The optimal configuration set of STFT variables aiming at risk stratification for sustained monomorphic ventricular tachycardia (SMVT) is still undetermined. Different configuration variables, including analyzing time-window widths, starting positions, relative displacements, and zero-padding for STFT time-frequency maps constructions were combined on each analyzing averaged signal from 18 healthy controls and 18 subjects presenting inducible SMVT. Spectral turbulence analysis (STA) was, thus, carried out according to conventional procedures. The optimal configuration set of variables for STA was obtained by assessing the total diagnostic accuracy of all combinations of parameters. The optimal diagnostic performance was found at 86% total diagnostic accuracy as compared to 56% using previous defined normality thresholds (p=0.01). Present configuration set of variables is distinctive from previously defined set of variables and improves risk stratification.

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O eletrocardiograma de alta resolução no domínio da freqüência. Utilização de técnicas estatísticas de correlação espectral para identificação de pacientes com taquicardia ventricular monomórfica sustentada

Cited by 9 publications

References 16 publications

Analysis of the Prevalence of Ventricular Late Potentials in the Late Phase of Myocardial Infarction Based on the Site of Infarction

Analysis of the Prevalence of Ventricular Late Potentials in the Late Phase of Myocardial Infarction Based on the Site of Infarction

Atrial activation during sinus rhythm in patients with rheumatic and non-rheumatic paroxysmal atrial fibrillation. Frequency-domain analysis using signal-averaged electrocardiography

The effect of configuration parameters of time-frequency maps in the detection of intra-QRS electrical transients of the signal-averaged electrocardiogram: Impact in clinical diagnostic performance

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