signal-averaged electrocardiogram

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Original Article

Detection of incipient left ventricular hypertrophy in mild to moderate arterial hypertension with normal electrocardiogram and echocardiogram: a new use for signal-averaged electrocardiography

Paulo Ginefra et al. Eduardo C. Barbosa P. R. Benchimol-Barbosa Alfredo S. Bomfim … Sílvia H. Boghossian Angelo A. Salgado Flávia G. Brasil Elizabete A. Freitas Francisco M. Albanesi Filho

OBJECTIVE: To assess signal-averaged electrocardiogram (SAECG) for diagnosing incipient left ventricular hypertrophy (LVH). METHODS: A study with 115 individuals was carried out. The individuals were divided as follows: GI – 38 healthy individuals; GII – 47 individuals with mild to moderate hypertension and normal findings on echocardiogram and ECG; and GIII – 30 individuals with hypertension and documented LVH. The magnitude vector of the SAECG was analyzed with the high-pass cutoff frequency of 40 Hz through the bidirectional four-pole Butterworth high-pass digital filter. The mean quadratic root of the total QRS voltage (RMST) and the two-dimensional integral of the QRS area of the spectro-temporal map were analyzed between 0 and 30 Hz for the frequency domain (Int FD), and between 40 and 250 Hz for the time domain (Int TD). The electrocardiographic criterion for LVH was based on the Cornell Product. Left ventricular mass was calculated with the Devereux formula. RESULTS: All parameters analyzed increased from GI to GIII, except for Int FD (GII vs GIII) and RMST log (GII vs GIII). Int TD showed greater accuracy for detecting LVH with an appropriate cutoff > 8 (sensitivity of 55%, specificity of 81%). Positive values (> 8) were found in 56.5% of the G II patients and in 18.4% of the GI patients (p< 0.0005). CONCLUSION: SAECG can be used in the early diagnosis of LVH in hypertensive patients with normal ECG and echocardiogram.

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Original Article

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

P. R. Benchimol-Barbosa et al. Marcos Oliveira de Sousa Eduardo Correa Barbosa Alfredo de Souza Bomfim … Paulo Ginefra Jurandir Nadal

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: The prevalence of VLP in a late phase after MI (median of 924 days) in anterior/antero-septal and inferior/infero-dorsal wall lesion was analyzed using signal-averaged electrocardiogram in time domain. The diagnostic performance of the filters employed for analysis on was tested at high-pass cut-off frequencies of 25 Hz, 40 Hz and 80 Hz. RESULTS: The duration of the ventricular activation and its terminal portion were larger in inferior than anterior infarction, at high-pass cut-off frequencies of 40 Hz and 80 Hz. In patients with ventricular tachycardia, these differences were more remarked. The prevalence of ventricular late potentials was three times greater in inferior than anterior infarction. CONCLUSION: Late after myocardial infarction, the prevalence and the duration of ventricular late potentials are greater in lesions of inferior/infero-dorsal than anterior/antero-septal wall confirming their temporal process, reflecting their high-frequency content.

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Artigo Original

Evaluation of fragmented potentials in the presence of right bundle branch block without structural myocardium abnormalities by using signal-averaged electrocardiogram on time and frequency domain

Paulo Ginefra et al. Eduardo C. Barbosa Luiz A. Christiani Maria de Fátima M. P. Leite … P. R. Benchimol-Barbosa Sílvia H. Boghossian Mônica Scott Isabela M. T. Rangel Rosângela S. Silva Francisco M. Albanesi Fº

PURPOSE: To evaluate if the presence of right bundle branch block (RBBB), without structural myocardial abnormalities (SMA) can generate fragmented potentials (FP) and spectral turbulence on signal-averaged electrocardiogram (SAECG). METHODS: Twelve children with atrial septal defect (ASD) and incomplete right bundle branch block (IRBBB without SMA (group I) were compared to 17 children with post-operative tetralogy of Fallot (TF) with CRBBB, all with SMA, 5 with ventricular premature beats and 2 with sustained ventricular tachycardia (group II). All had SAECG on time (TD) and frequency domain (FD) with 5 variables analysed. RESULTS: All patients of group I had normal variables, in contrast with group II which presented abnormal variables suggesting FP and ST. CONCLUSION: In ASD without SMA, the isolated IRBBB did not generate FP and ST.

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Artigo Original

Time domain analysis of the signal averaged electrocardiogram to detect late potentials in heart failure patients with different etiologies

Ernani de Sousa Grell et al. Rogério Silva de Paula Nancy Maria Martins de Oliveira Tobias Paulo Jorge Moffa … César José Grupi Alfredo José Mansur

OBJECTIVE: To evaluate the frequency, clinical correlations and prognosis influence of late potentials on the of heart failure patients with different etiologies using the signal averaged electrocardiogram. METHODS: A 42 month study of the signal averaged electrocardiograms of 288 heart failure patients with different etiologies was conducted. The group of patients included 215 males (74.65%) and 73 females (25.35%) between the ages of 16 and 70 (mean 51.5, standard deviation 11.24). The heart failure etiologies were: hypertensive heart disease (78 patients, 27.1%); idiopathic dilated cardiomyopathy (73 patients, 25.4%); ischemic cardiomyopathy (65 patients, 22.6%); Chagas disease (42 patients, 14.6%); alcoholic cardiomyopathy (9 patients, 3.1%); peripartum cardiomyopathy (6 patients, 2.1%); valvular heart disease (2 patients, 4.2%) and viral myocarditis (3 patients, 1.04%). The variables included the duration of the standard QRS complex, duration of the filtered QRS complex, duration of the signal below 40µV and the root mean square of the last 40ms which were analyzed in regard to age, gender, etiology and mortality as well as the findings of the 12-lead electrocardiogram at rest, echocardiogram and ambulatory electrocardiogram. The statistical analysis tests used were: the Fisher exact probability test, Student’s t-test, Mann Whitney test, variance analysis, Log-Hank and the Kaplan-Meyer method. RESULTS: Late potentials were diagnosed in 90 patients (31.3%) and there was no association with the etiologies. The presence of this condition is associated with: a lower maximum oxygen uptake during the ergospirometry (p=0.001); sustained and non-sustained ventricular tachycardia during Holter monitoring (p=0.001), sudden death and mortality (p<0.05). Patients that did not present late potentials had a higher overlife rate. CONCLUSION: The presence of late potentials was not associated with the etiologies and proved to be an indication of a worse prognosis.

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Detection of incipient left ventricular hypertrophy in mild to moderate arterial hypertension with normal electrocardiogram and echocardiogram: a new use for signal-averaged electrocardiography

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

Evaluation of fragmented potentials in the presence of right bundle branch block without structural myocardium abnormalities by using signal-averaged electrocardiogram on time and frequency domain

Time domain analysis of the signal averaged electrocardiogram to detect late potentials in heart failure patients with different etiologies

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Electronic Document Format (ISO)

Electronic Document Format (Vancouver)

Electronic Document Format (ABNT)

Electronic Document Format (APA)

Electronic Document Format (ISO)

Electronic Document Format (Vancouver)

Electronic Document Format (ABNT)

Electronic Document Format (APA)

Electronic Document Format (ISO)