Signal-averaged Electrocardiogram In Patients Research Articles

Signal-averaged electrocardiography as a noninvasive tool for evaluating the ventricular substrate in patients with nonischemic cardiomyopathy: reassessment of an old tool.

Signal-averaged electrocardiography (SAECG) provides diagnostic and prognostic information regarding cardiac diseases. However, its value in other nonischemic cardiomyopathies (NICMs) remains unclear. This study aimed to investigate the role of SAECG in patients with NICM. This retrospective study included consecutive patients with NICM who underwent SAECG, biventricular substrate mapping, and ablation for ventricular arrhythmia (VA). Patients with baseline ventricular conduction disturbances were excluded. Patients who fulfilled at least one SAECG criterion were categorized into Group 1, and the other patients were categorized into Group 2. Baseline and ventricular substrate characteristics were compared between the two groups. The study included 58 patients (39 men, mean age 50.4 ± 15.5 years), with 34 and 24 patients in Groups 1 and 2, respectively. Epicardial mapping was performed in eight (23.5%) and six patients (25.0%) in Groups 1 and 2 (p = 0.897), respectively. Patients in Group 1 had a more extensive right ventricular (RV) low-voltage zone (LVZ) and scar area than those in Group 2. Group 1 had a larger epicardial LVZ than Group 2. Epicardial late potentials were more frequent in Group 1 than in Group 2. There were more arrhythmogenic foci within the RV outflow tract in Group 1 than in Group 2. There was no significant difference in long-term VA recurrence. In our NICM population, a positive SAECG was associated with a larger RV endocardial scar, epicardial scar/late potentials, and a higher incidence of arrhythmogenic foci in the RV outflow tract.

Analysis of site-specific late potentials using a novel Holter signal-averaged electrocardiography in patients with Brugada syndrome.

The utility of late potentials on signal-averaged electrocardiography (SAECG) for risk stratification in patients with Brugada syndrome (BrS) remains controversial. Late potentials on conventional SAECG with Frank leads may be insufficiently sensitive to detect site-specific late potentials in right precordial leads. The purpose of this study was to evaluate the utility of site-specific late potentials using a novel unipolar Holter-SAECG system for risk stratification in patients with BrS. Consecutive symptomatic (n = 20) and asymptomatic (n= 21) patients with BrS who underwent investigation using conventional SAECG and a novel unipolar Holter-SAECG system were enrolled. We evaluated clinical characteristics and outcomes and compared late potentials on the 2 SAECGs between both groups and patients with and without cardiac events (CEs) (sudden cardiac death or sustained ventricular tachyarrhythmias) during the follow-up period. During mean follow-up of 76 months, 10 patients (24%) had CEs. There were no significant differences in late potentials on conventional SAECG between symptomatic and asymptomatic patients. On the Holter-SAECG system, RMS40 in lead V2 in the third intercostal space (3L-V2) at the nighttime was significantly lower in the symptomatic group than in the asymptomatic group (5.5±0.8 μV and 8.2 ± 0.8 μV, respectively; P = .027). Univariate analysis of predictive values for CE showed that hazard ratios of daytime and nighttime RMS40 in lead 3L-V2 of <7.7 μV and <6.1 μV were 7.58 and 6.14, respectively. Site-specific late potentials in lead 3L-V2 measured using the novel Holter-SAECG system may be a useful marker for high-risk patients with BrS.

The role of revascularization on short-term Heart Rate Variability (HRV) and Signal Averaged Electrocardiogram (SAECG) in Stable Coronary Artery Disease (CAD)

Background: Revascularization in patients with stable coronary artery disease (SCAD) can reduce myocardial ischemia and improves the autonomic nervous system, which can be measured by heart rate variability (HRV) and signal-averaged electrocardiogram (SAECG). This study aimed to investigate the effect of revascularization on HRV and SAECG in patients with SCAD. Methods: This is a single-center prospective cohort study. Revascularization refers to percutaneous coronary intervention (PCI). The primary outcome of this study is the change in short-term HRV and SAECG from before revascularization to after revascularization. HRV and SAECG measurement was performed for 10 minutes before PCI and one-month post-PCI. Data were analyzed using SPSS version 23 for Windows. Results: There are 30 patients included in this study, and 46.7% underwent incomplete PCI. There was no significant difference in HRV parameters in the time domain method. In the frequency domain, only the LF/HF ratio changed significantly from 3.5±2.6 before PCI to 2.16±1.9 after PCI, with a 1.33 decrease in LF/HF (p=0.007). Subgroup analysis was performed for patients receiving complete and incomplete revascularization. In patients who received complete revascularization, there was a significant difference in LF/HF ratio change of 1.6±2.28 (p=0.013). In patients that receive incomplete revascularization, there is a significant increase in HF 37.8±57.3 (p=0,028). In terms of SAECG parameters, there is no significant difference between before and after PCI in both primary and subgroup analysis. Conclusion: Revascularization resulted in a significant reduction in LF/HF ratio assessed by short-term HRV. There was no benefit of revascularization in terms of SAECG parameters.

Risk stratification in patients with Brugada syndrome: the role of the late potentials evaluated by signal-averaged ECG

Abstract Introduction Brugada syndrome (BS) is a relevant cause of sudden death in individuals without structural heart disease. The accuracy of the available methods for risk stratification is very limited and the investigation of new methodologies to improve the identification of patients at risk is under intensive investigation. Recently the pathophysiological relevance of anomalous, fragmented and prolonged electrograms on the epicardial surface of the right ventricular outflow tract (RVOT) has been described. Therefore, the study of signal-averaged ECG (SA-ECG) has become attractive since it may allow the non-invasive evaluation of these electrical anomalies. In order to maximize the detection capacity and to focus the evaluation in the RVOT, we developed an alternative methodology of electrode positioning directed to this area of interest. Purpose To characterize the study of late potentials (LP) by SA-ECG in patients with SB and to evaluate its association with the occurrence of arrhythmia events. Methods Prospective single centre study of patients (pts) with BS. LP were evaluated by SA-ECG with determination of the total filtered QRS duration (fQRS), root mean square voltage of the 40 ms terminal portion of the QRS (RMS40) and duration of the low amplitude electric potential component (40 microV) of the terminal portion of the QRS (LAS40) in conventional and modified leads (addressed to RVOT). The association of LP with the risk of definite malignant dysrhythmias due to sudden death, ventricular fibrillation, ventricular tachycardia or appropriate shock of the implantable cardioverter defibrillator (ICD) was evaluated and the acuity of the prognostic stratification was determined by the area under the receiver operator characteristic curve (ROC). Results A total of 76 pts (69.7% men, age 48±12 years) were studied, of which 33 had a spontaneous type 1 pattern and 43 had a type 1 pattern induced by flecainide. During a median follow-up of 1.6 years, 13 pts (17.1%) had symptoms potentially related to BS and 6 (10.5%) had malignant arrhythmias [including two pts who suffered sudden death (2.6%). The pts who had malignant dysrhythmias presented higher values of fQRS (125±23 vs. 108±18, p=0.046) and LAS40 (54±13 vs. 40±11, p=0.014), and lower values of RMS40 only in the modified leads (11±5 vs. 22±19, p=0.041). The parameters of the SA-ECG were significant prognostic predictors. The acuity of each of the parameteres alone was moderate and the parameters that were identified as more powerful predictors of risk were those derived from the modified leads (Figure). Conclusion The LP evaluated by SA-ECG may be relevant in the prognostic stratification of patients with BS, since it seems to be associated with the risk of malignant ventricular arrhythmias. Funding Acknowledgement Type of funding sources: None.

Noninvasive prediction of late potentials in the signal-averaged ECG in patients with chronic Chagas disease

IntroductionConsidering the importance of ventricular arrhythmias in the prediction of sudden cardiac death in chronic Chagas heart disease, the aim of the present study was to associate late potentials observed in the signal-averaged electrocardiogram (SAECG) with either non-sustained ventricular tachycardia in the 24-hour Holter monitoring or reduced left ventricular ejection fraction in the 2-dimension echocardiogram. MethodsThis was a retrospective transversal study. The medical charts of 49 patients with chronic Chagas heart disease that underwent 24-hour Holter monitoring at our institution from September 2012 to December 2015 were reviewed. In the univariate analysis, variables associated with SAECG at a p value <0.05 were entered a multivariate stepwise logistic regression analysis through the model forward. A p value <0.05 was considered to have statistical significance. ResultsIn the univariate analysis, right bundle branch block, left atrial diameter, left ventricular systolic diameter, and left ventricular ejection fraction were associated with late potential in the SAECG. In the multivariate analysis, however, right bundle branch block and left atrial diameter were retained as independent predictors of late potentials in the SAECG. ConclusionsNeither ventricular arrhythmias in the 24-Holter monitoring nor reduced left ventricular ejection fraction in the 2-D echocardiogram were associated with late potentials in the SAECG of patients with chronic Chagas heart disease.

P5350Atrial fibrillation prediction using P wave signal-averaged ECG in patients with embolic stroke of undetermined source

Abstract Background Approximately 10–25% of ischemic strokes are of unknown origin. Determining their potential association with subclinical atrial fibrillation (SCAF) is important for proper secondary prevention. We investigated whether SCAF can be predicted by assessing the atrial substrate with signal-averaged electrocardiography (SAECG). Methods Between April 2015 and February 2018, we recruited 125 consecutive patients with embolic stroke of undetermined source (ESUS) and 125 patients with paroxysmal atrial fibrillation (AF) patients as control. All participants underwent P wave SAECG at baseline and ESUS patients were followed up with ECG and Holter ECG, at baseline, 3, 6, and 12 months after discharge, and every 12 months thereafter. Results In the ESUS group (69 males, 68.4±12.1 years), 32 (25.6%) patients were diagnosed with SCAF during follow-up. There were no significant differences between both groups in terms of P wave duration [PWD] (ESUS vs. AF, P=0.321). PWD demonstrated a significant predictive efficacy for SCAF detection during follow-up (C-index of standard PWD=0.657, 95% confidence interval (CI) 0.552–0.761, P=0.008). Stroke recurrence occurred in 22 patients (17.6%) and was significantly associated with PWD but not SCAF (odds ratio 2.756, 95% CI 1.061–7.161, P=0.037). Conclusion PWD, an ECG biomarker associated with atrial substrate directly contributes to AF and ESUS, is useful for predicting SCAF. The potential for using this simple ECG biomarker for screening for SCAF amongst ESUS patients merits further exploration.

Cardiac Electrical Vulnerability after Acute Myocardial Infarction Associated with Respiratory Infections

Heart rate variability and the presence of late potentials are independent predictor factors for cardiac death and electrical vulnerability of the ischemic myocardium, especially after myocardial infarction(MI). Respiratory infection are known to be associated with MI both through direct action of the pathogen and by altering the hemodynamic status, through tachycardia and a rise in myocardial oxigen demand. Our paper wants to highlight that respiratory infection during subacute and late recovery phase of myocardial infarction can aggravate the electrical vulnerability of the myocardium and increases the arrhythmic risk. We analysed heart rate variability and the presence of late potentials on signal-averaged ECG in patients who developed acute respiratory infection after MI. All parameters of heart rate variability were signifficantly decreased in our target group. Incidence of late potentials did not differ between the two groups, meaning that the electrophysiological substrate of arrhythmias was not influenced by respiratory infection. Ventricular arrhythmias were more severe and frequent in the infection group. Respiratory infectious disease in early and late recovery phase after acute myocardial infarction, increases the risk of life threatening arrhythmias. It must be emphasized the need to consider prevention and early treatment of respiratory viral or bacterial infections, particularly in patients with cardiac ischemic disease.

P5529Difference of late potentials detected by signal-averaged ECG in patients with spontaneous or drug-induced type 1 electrocardiogram pattern of Brugada syndrome

Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017.

Prevalence of late potentials on signal-averaged ECG in patients with psychiatric disorders

BackgroundSudden cardiac death (SCD) occurs three times more often in psychiatric patients than in the general population. QRS fragmentation (QRSfr) and signal-averaged electrocardiography (SAECG) are simple, inexpensive, readily available tools for detecting the presence of abnormal depolarization and late potentials (LPs) in these patients, a result of either the underlying disease or treatment. MethodsFrequency of LP detection by SAECG and QRSfr was studied in 52 psychiatric patients and compared with 30 healthy (without known structural heart disease or occurrence of ventricular arrhythmia) controls. Patients were then prospectively followed up and incidence of SCD was recorded. ResultsLP prevalence was significantly higher in patients than in controls (16/52–31% vs 2/30–7%, p=0.012), while QRSfr was similar between these two groups (p=0.09). Of the LP presence criteria, the root mean square value at terminal 40msec of the QRS (RMS40) was significantly lower in patients (32μV, SD=19μV, vs 46μV, SD=32μV, p=0.015). Among patients, no differences were noted between the LP positive and negative groups regarding age, sex, number of medications, class of antipsychotics and defined daily doses. Mean follow-up was 46months (SD=11) and during it 3 patients suffered SCD. Although 2 SCD victims had both LPs and QRSfr concurrently present, neither of them, nor their simultaneous presence could definitely account for the events. ConclusionsLP prevalence in psychiatric patients was significantly higher than in controls. SAECG performance was feasible in all cases and constitutes a readily available tool for assessing myocardial electrophysiological alterations in this patient group.

136-72: Late potentials detected by signal-averaged ECG in patients with spontaneous and drug-induced type 1 electrocardiogram pattern of Brugada syndrome

136-72: Late potentials detected by signal-averaged ECG in patients with spontaneous and drug-induced type 1 electrocardiogram pattern of Brugada syndrome

P Wave Signal-Averaged Electrocardiography in Patients with Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD) is associated with higher incidence of supraventricular arrhythmias. Atrial late potentials (ALP) detected by P-wave signal-averaged electrocardiography (SAECG) could be useful in detecting the patients at risk for supraventricular arrhythmias. Our objective was to assess the role of P-wave SAECG and ALP detection for arrhythmic risk evaluation of the patients with exacerbated COPD. We prospectively included 45 patients with exacerbation of COPD and 58 age- matched patients with no history of pulmonary disease in a control group. We performed pulmonary function tests, arterial blood gases, echocardiography, 24-hour Holter monitoring and P-wave SAECG. We measured filtered P-wave duration (FPD), the root mean square (RMS) voltages in the last 40, 30 and 20 ms of the filtered P-wave (RMS 40, RMS 30 and RMS 20), the root mean square voltage of the filtered P-wave potentials (RMS-p), and the integral of the potentials during the filtered P-wave (Integral-p). ALP was defined as FPD > 132 ms and RMS 20 < 2.3 μV. Isolated atrial premature beats (APB) and supraventricular tachycardias (SVT) were more frequent in the COPD group. There were no significant differences between groups regarding the P wave SAECG parameters. In the COPD group none of the supraventricular arrhythmias was correlated with ALP or any P-wave SAECG parameters. The patients with acute exacerbation of COPD but no apparent cardiac disease have a higher incidence of supraventricular arrhythmias. P-wave SAECG analysis and ALP detection have little value in the arrhythmic risk evaluation of these patients.

Changes in Follow‐Up ECG and Signal‐Averaged ECG in Patients with Arrhythmogenic Right Ventricular Cardiomyopathy

Electrocardiogram (ECG) and signal-averaged ECG (SAECG) are important as diagnostic tools in arrhythmogenic right ventricular cardiomyopathy (ARVC). The aim of this study was to investigate changes in follow-up ECGs and SAECGs in patients with ARVC. We collected 185 follow-up ECGs from 38 patients and 35 follow-up SAECGs from 18 patients during a mean follow-up period of 64 ± 36 months. On baseline ECG and SAECG, epsilon waves, T-wave inversion (TWI), and terminal activation delay (TAD) of QRS ≥ 55 ms in right precordial leads, and late potentials (LPs) were observed in six (16%), 11 (29%), 13 (34%), and 23 (68%) patients, respectively. During the follow-up period, 15 (39%) patients had 18 changes in ECG and/or SAECG features included in modified Task Force Criteria (TFC) of ARVC. Two patients developed new epsilon waves, and another two patients had dynamic epsilon waves. Newly developed TAD of QRS ≥ 55 ms was observed in two patients and disappeared in one patient. Eight patients, seven with and one without TWI in V1 -V3 or beyond, showed dynamic changes. LP developed in three patients. One patient with dynamic change of TWI and another patient with dynamic change of epsilon wave and TAD of QRS ≥ 55 ms could not satisfy the modified TFC during follow-up. Follow-up ECGs and SAECGs showed changes in 39% of patients with ARVC. Larger studies with a longer follow-up period are needed to investigate the clinical implications of changes in follow-up ECG and SAECG.

第4回 体表心臓微小電位研究会 洞不全症候群におけるP波同期式体表面加算平均心電図の臨床的意義

第4回 体表心臓微小電位研究会 洞不全症候群におけるP波同期式体表面加算平均心電図の臨床的意義

Short-term effects of eicosapentaenoic acid on P wave signal-averaged electrocardiogram in patients with coronary artery disease

The antiarrhythmic properties of n-3 polyunsaturated fatty acids (PUFAs) have been demonstrated in experimental models and in patients with coronary artery disease [1–6]. On the other hand, the signal-averaged electrocardiogram (SAECG) of the P waves has been used to predict the development of atrial fibrillation by measuring the filtered P wave duration (FPD) as an index of atrial conduction delay with high accuracy [7–10]. In this study, we assessed whether key long-chain n-3 PUFA, eicosapentaenoic acid (EPA) affected parameters of P wave SAECG in patients with coronary artery disease.

Risk Assessment of Asymptomatic Paroxymal Atrial Fibrillation by Using the P-Wave Signal-Averaged Electrocardiogram in Patients with Chronic Kidney Disease

Risk Assessment of Asymptomatic Paroxymal Atrial Fibrillation by Using the P-Wave Signal-Averaged Electrocardiogram in Patients with Chronic Kidney Disease

Mechanism of low amplitude potentials at the initial portion of the P wave signal-averaged electrocardiogram in patients with sick sinus syndrome

Mechanism of low amplitude potentials at the initial portion of the P wave signal-averaged electrocardiogram in patients with sick sinus syndrome

Signal-averaged ECG parameters in patients with hypertensive disease with different types of diurnal blood pressure variations

The purpose of the present study was to estimate the parameters of signal-averaged ECG in patients with hypertensive disease (III)) with different types of diurnal blood pressure (BP) variations. The study covered 127 patients aged 30 to 73 years (mean 53.4 ± 9.7 years) who Stages I-II HD. All the patients underwent estimation of late ventricular potentials (LVP) by recording signal-averaged ECG (SA-ECG) and 24-hour BP monitoring (24-h BPМ). The study did not reveal significant differences in the recording of LVP and in the parameters of SA-ECG in patients with HD with varying degrees of arterial hypertension. This was also confirmed by the fact that there were no significant differences in the parameters of 24-h BPM in the groups of hypertensive patients with and without LVP. In patients with BP, the impaired diurnal BP variations were ascertained to be associated with the increased detection rate of LVP. The most pronounced deterioration of SA-ECG parameters was observed in patients with an excessive nocturnal Ml' lowering the over-dipper type. In patients with HD, even an isolated excessive nocturnal diastolic BP lowering was shown to be followed by worse SA-ECG parameters. The findings are also supported by the correlations found between the parameters of SA-ECG and the values of 24-h BPM.

Autonomic cardiac rhythm regulation and the parameters of signal-averaged ECG in patients with hypertensive disease

The study was undertaken to evaluate autonomic cardiac rhythm regulation in patients with hypertensive disease (HD) in the presence and absence of late ventricular potentials (LVPs) Eighty five hypertensive patients aged 30 to 73 years (mean age 54±9 years) were examined In all the patients, LVPs were recorded by signal-averaged ECG and cardiac rhythm variability was analyzed This study revealed that in a group of HD patients with detected LVPs, cardiac rhythm variability was less than that in those without LVPs The HD patients with detected LVPs showed an increase in their sympathetic impact on cardiac rhythm regulation, as manifested by significantly higher LF/HF ratios (1,85±0,21 and 1,15±0,15, respectively,p<0,05) than did the patients without LVPs This is also confirmed by a moderate positive correlation between LF/HF and TotalQRS r=0,43,p=0,0001

Usefulness of spatial dispersion of QRS duration in predicting mortality in patients with mild to moderate chronic heart failure

To prospectively evaluate the prognostic significance of spatial dispersion of QRS duration (S-QRSd) on a signal-averaged electrocardiogram in patients with chronic heart failure (CHF), we studied 114 consecutive stable outpatients with radionuclide left ventricular ejection fraction <40%. Cardiac and sudden deaths were significantly more often observed in patients with than without abnormal S-QRSd. S-QRSd is a powerful prognostic marker of the mortality in patients with mild to moderate CHF.

10.8 Prognostic significance of consecutive abnormal signal-averaged electrocardiograms in patients after acute myocardial infarction

10.8 Prognostic significance of consecutive abnormal signal-averaged electrocardiograms in patients after acute myocardial infarction