Ventricular Late Potentials Research Articles

Effects of endothelin A receptor blockade in patients with ST-elevation acute coronary syndrome — A rhythmologic substudy

AimsVentricular arrhythmias are common after acute myocardial infarction (AMI). Endothelin (ET) is a mediator of microvascular dysfunction and cardiac remodeling with arrhythmogenic potential. The aim of this study was to assess safety and feasibility of selective ET-A receptor blockade in ST-elevation acute coronary syndrome (STE-ACS) within a larger randomized trial. Main methodsPatients with posterior-wall STE-ACS were randomly assigned to receive intravenous BQ-123 at 400nmol/min or placebo over 60min, starting immediately prior to primary percutaneous coronary intervention. Twenty-four hour Holter recordings were performed during hospitalization for STE-ACS and after 6–8weeks. The predefined primary endpoint was the documentation of ventricular tachycardia and/or late potentials at follow-up. Key findingsThere was no significant difference in the predefined primary endpoint at 45 (33–62) days (0/16 (0%) in BQ-123 treated patients vs. 1/14 (7%) in the placebo group, p=0.465). At 2 (1–3) days, an increase in the total number of supraventricular extrasystoles (SVES)/24h in patients randomized to BQ-123 (45 (17–165) beats vs. 11 (5–72) beats in placebo treated patients, p=0.025) occurred. This increase was also observed at 45days (105 (37–216) beats vs. 11 (3–98) beats in placebo treated patients, p=0.037). There was no significant difference regarding other rhythmologic secondary endpoints between the two groups. SignificanceBased on the analysis of long-term ECG data, short-term administration of BQ-123 after AMI was safe. Because of the small sample size, no firm conclusion regarding antiarrhythmic efficacy can be drawn.

Analysis of the spatial and transmural dispersion of repolarization and late potentials derived using signal-averaged vector-projected 187-channel high-resolution electrocardiogram in patients with early repolarization pattern

BackgroundElectrophysiological characteristics of early repolarization syndrome (ERS), i.e., the spatial and transmural dispersion of ventricular repolarization and ventricular late potentials can be evaluated using a signal-averaged vector-projected 187-channel high-resolution electrocardiogram (187-ch SAVP-ECG). We investigated these characteristics as markers of ventricular fibrillation and sudden cardiac arrest in patients presenting with an ER pattern. MethodsThe 187-ch SAVP-ECGs were recorded for 8 patients with idiopathic ventricular fibrillation associated with ERS (ERS patients), and 5 patients with an ER pattern without arrhythmic events (ER pattern patients). ResultsThe ER pattern was located in the inferior leads (n=7), lateral leads (n=1), or both inferior and lateral leads (n=5). The corrected RT(RTc) (peak point of the R wave − positive maximum peak of the first derivative of the T wave interval corrected using the Bazett formula) interval and T(peak-end)-c interval from the 187 channels were calculated. Late potentials were positive in 7 of 8 ERS patients and in 3 of 5ER pattern patients (P=0.25). The average RTc was shorter in patients with ERS (192.6±29.8ms vs. 234.0±25.5ms, P=0.04). However, average T(peak-end)-c interval did not differ between the 2 groups. ConclusionLate ventricular potentials were common in ERS and ER pattern patients. Lethal arrhythmia in ERS patients appeared to be related to the relatively short average repolarization time rather than the spatial and transmural dispersion of repolarization.

THE EFFICACY OF MELDONIUM IN REDUCTION OF CARDIAC ELECTRICAL INSTABILITY IN PATIENTS WITH ISCHEMIC STROKE

Aim. To study meldonium effect in the combination therapy for ventricular repolarization disorders and cardiac electrical instability in patients with ischemic stroke. Material and methods. Patients (n=46) with acute phase of ischemic stroke were included in a randomized, open-label, uncontrolled study. Patients were randomized into two groups. Group 1 patients (n=25) had been receiving meldonium (Mildronate;Grindex,Latvia;Pharmstandard,Russia), 1.0 g/day intravenously once daily, as a part of standard therapy for 10 days since admission to the hospital. Group 2 patients (n=21) had standard therapy alone. A standart 12-lead ECG, ventricular late potentials (VLP), 24-hour Holter monitoring, troponin test were performed at the baseline and after 10 days. Results. Patients of the group 1 as compared to the group 2 demonstrated more significant positive effect on the clinical condition of patients with ischemic stroke, ventricular repolarization, reduction of frequency (from 3.7±0.5 to 2.1±0.4; p<0.05) and duration (from 6.6±1, 3 to 4.0±1.1 min; p<0.05) of painless myocardial ischemia episodes and VLP (from 48 to 32%). Conclusion. Adding meldonium to standard therapy in patients with acute phase of ischemic stroke can have a positive effect on the clinical condition, repolarization disorders on ECG, frequency of VLP and episodes of painless myocardial ischemia detection. This may have a positive effect on the electrical stability and prevention of cardiac arrhythmias.

The Application of FastICA Combined with Related Function in Blind Signal Separation

Blind source separation (BSS) has applications in the fields of data compression, feature recognition, speech, audio, and biosignal processing. Identification of ECG signal is one of the challenges in the biosignal processing. Proposed in this paper is a new method, which is the combination of related function relevance to estimated signal and negative entropy in fast independent component analysis (FastICA) as objective function, and the iterative formula is derived without any assumptions; then the independent components are found by maximizing the objective function. The improved algorithm shorthand for R-FastICA is applied to extract random mixed signals and ventricular late potential (VLP) signal from normal ECG signal; simultaneously the performance of R-FastICA algorithm is compared with traditional FastICA through simulation. Experimental results show that R-FastICA algorithm outperforms traditional FastICA with higher similarity coefficient and separation precision.

The influence of intravenous ozone therapy on the electrophysiological properties of myocardium during combined treatment of the patients presenting with arterial hypertension

The present investigation included 65 patients (36 men and 29 women of the mean age of 51.3 +/- 6.7 years) presenting with grade I-II arterial hypertension (AH) and undergoing intravenous ozone therapy in combination with the intake of antihypertensive preparations. ECG studies showed that a course of ozone therapy decreases the degree of in homogeneity of intra-myocardial electrophysiological processes in the patients with AH as apparent from reduced dispersion of P-wave and corrected QT-interval. Analysis of the results of high-resolution ECG revealed a significant decrease in the frequency of ventricular late potentials from 29.2% (19 patients) to 13.8% (9 patients) (chi2=4.5; p=0.03) whereas the decrease in the frequency of atrial late potentials was insignificant, from 40% (26 patients) to 29.2% (19 patients) (chi2=1.67; p=0.19). The results of spectral-temporal mapping indicate that a course of ozone therapy resulted in a significant decrease of the total number of local peaks in the QRS complex and the number of peaks with low-amplitude and high-frequency characteristics.

Principal component analysis in high resolution electrocardiogram for risk stratification of sustained monomorphic ventricular tachycardia

Ventricular late potentials (VLP) are low amplitude and high frequency transients registered on high resolution electrocardiogram (HRECG), markers of life threatening ventricular tachyarrhythmia. This study assessed a novel VLP group classification method based on principal components (PC) analysis. Thirty-six subjects (mean±SD; 55.4±11.6 years) divided in two groups, 18 healthy controls and 18 patients with induced sustained monomorphic ventricular tachycardia were included. Four PC data matrix from HRECG signal averaged with no further filtering leads were built, taking QRS onset as reference. Mahalanobis distance calculation combined with classification by logistic regression determined optimal separation threshold between groups for each matrix. HRECG signals were also analyzed using classical approaches. ROC curve analyzes compared novel and classical methods (α<0.05). The optimal configuration retained seven initial PCs. Average c-statistic was 0.99 for PC method and 0.65 for classical methods taken together (p<0.05). PC analysis increases diagnostic accuracy for VLP group classification with potential clinical application.

Long-term Cardiovascular Toxicity in Children, Adolescents, and Young Adults Who Receive Cancer Therapy: Pathophysiology, Course, Monitoring, Management, Prevention, and Research Directions

Cancer is diagnosed in >12 000 children and adolescents in the United States each year.1 Progress in cancer therapeutics over the past 40 years has remarkably improved survival rates for most childhood malignancies. For all pediatric cancers, 5-year survival increased from 58% for children diagnosed between 1975 and 1977 to 82% for those diagnosed between 1999 and 2006.2 In the United States, this success translates into >325 000 survivors of childhood cancer, of whom 24% are now >30 years from diagnosis.3 During this same period, the incidence of many histological subtypes of childhood cancer has increased, including acute lymphoblastic leukemia (ALL), acute myeloid leukemia, non-Hodgkin lymphoma, neuroblastoma, and soft-tissue and germ-cell tumors.3 Consequently, the number of childhood cancer survivors is expected to increase as a result of the rising pediatric cancer incidence and improved long-term survival rates.3 The increasing number of survivors soon revealed acute and delayed modality-specific toxicities and their impact on quality of life and early mortality. In their seminal 1974 publication, Meadows and D’Angio4 described the wide array of potential late effects of successful therapy for childhood cancer. In the past 2 decades, the Childhood Cancer Survivor Study has also improved our understanding of the long-term mortality and morbidity in this high-risk population. Among young adult survivors of childhood cancer diagnosed between 1970 and 1986, at least 1 of 6 domains of health status (general health, mental health, functional status, activity limitations, cancer-related pain, and cancer-related anxiety) declined moderately to severely in 44%.5 The cumulative incidence of a chronic health condition 30 years after cancer diagnosis is now 73%, with a cumulative incidence of 42% for severe, disabling, or life-threatening conditions or death attributable to a chronic condition.6 Also by 30 years after cancer diagnosis, the cumulative mortality rate from causes …

Single Guide League Ventricular Late Potentials Extraction Based on Signal Correlation

The detection and analysis of Ventricular Late Potentials (VLP) is a kind of effective means to predict patients with disease outbreaks clinically and understand ventricular mechanism, single guide league system will become a trend in future medicine. This paper proposes a Blind Source Separation (BSS) method to single guide league observed signal with correlation theory, this method will unify wavelet packet transformation and Independent Component Analysis (ICA), which can fully recover VLP, but the extracted ECG signal has distortion, in order to eliminate distortion, it is necessary to reduce the noises of extracted ECG signal, then the source signals can be estimated accurately. It is proved that the proposed method is effective, and able to solve underdetermined BSS, it can get better separation effect than the traditional FastICA algorithm that the number of source signals is equal to the number of observed signals.

The Extraction of Ventricular Late Potentials Based on Sparse Component Analysis

Blind source separation technology was applied to separate and extract different components from observed electrocardiograph signals. The electrocardiograph signal with ventricular late potentials presents the sparseness. Two-step approach of sparse component analysis was used in extraction of ventricular late potentials. An improved method of estimating the mixing matrix was proposed. It can improve estimation precision of mixing matrix about the source signals whose amplitudes have large difference in all or particular frequency bands, which realizes the source signal separation nondestructively. Simultaneously, the estimated signals are output in order solving the order uncertainty of independent component analysis. It is proved that sparse component analysis greatly enhances extraction precision of ventricular late potentials.

第3回 体表心臓微小電位研究会 健常人における加算平均心電図の検討

第3回 体表心臓微小電位研究会 健常人における加算平均心電図の検討

第1回 体表心臓微小電位研究会 心室頻拍例(sVT,nsVT)における心室遅延電位の検討

第1回 体表心臓微小電位研究会 心室頻拍例(sVT,nsVT)における心室遅延電位の検討

Change of the main parameters of 24-hour ekg monitoring in patients with myocardial infarction associated with ventricular arrhythmias

Aim. To study the change of the main parameters of 24-hour EKG monitoring over time in patients with myocardial infarction associated with ventricular arrhythmias of different grades. Methods. The change of the echocardiography parameters, heart rhythm variability, corrected QT interval duration and dispersion, late ventricular potentials, heart rhythm turbulence were examined in 70 adult men (mean age 52.6±1.3 years) with primary Q-wave myocardial infarction on 10-14th day of the disease and after 6 months. Patients were assigned into 3 groups depending on ventricular arrhythmias severity (according to Lown classification modified by Ryan): А1 (n=29) - grade 1-2, А2 (n=23) - grade 3-4, А3 (n=18) - patients with paroxysmal ventricular tachycardia. Results. Presence of late ventricular potentials and pathologic heart rhythm turbulence in patients in acute period of myocardial infarction suggested high grade of ventricular arrhythmia. Ventricular arrhythmias were associated with severe sympathicotonia, prolongation of corrected QT interval and QT dispersion. 6 months after Q-wave myocardial infarction an autonomic imbalance increased and no positive changes of myocardial homogenicity parameters, late ventricular potentials and pathologic heart rhythm turbulence were observed with increasing ventricular arrhythmia grading and heart rate frequency. A relationship between left ventricle ejection fraction, myocardium mass and myocardial electric non-stability values was revealed. In patients with Q-wave myocardial infarction ventricular arrhythmias are mediated by several mechanisms: systolic and autonomic disorder, repolarization abnormalities, late ventricular potentials pathologic heart rhythm turbulence. The severity of abnormalities is marked by the ventricular arrhythmias grade. Conclusion. 6 months after myocardial infarction (in healing stage) the significant positive changes are found only in patients with 1-2 grades ventricular arrhythmias. The significant non-homogeneity of myocardial electrophysiological features still persists in patients with life-threatening ventricular arrhythmias.

QRS complex duration enhancement as ventricular late potential indicator by signal-averaged ECG using time-amplitude alignments

Ventricular late potentials (VLPs) are small-amplitude waves with a short duration that appear at the end part of the QRS complex, making a QRS complex duration larger. The signal-averaged electrocardiography (ECG) technique enhances VLPs and beats, assuming noise as the only random variable. However, ECG signals are not completely stationary and different elongations appear in both time and amplitude in each beat. This research proposes to use piecewise linear approximation to segment each beat and performs the alignment of the beats using the technique known as derivative dynamic time-warping to have beats better aligned and consequently enhance the presence of VLPs. We recorded high-resolution ECGs (HRECGs) from 50 subjects in supine position with no heart-stroke antecedents. VLPs were created synthetically and added to the HRECGs. Two cases were evaluated: (i) duration of the QRS complexes with VLPs without beats alignment, and (ii) duration of QRS complexes with VLPs using beats alignment in time and amplitude. Considering QRS duration as an indicative of VLP presence, results show that when using beats alignment in time and amplitude it is possible to reach a sensitivity of 0.96 and a specificity of 0.52, as opposed to 0.72 and 0.40, respectively, when using only averaging without beats alignment in time and amplitude.

Spatial distribution of ventricular late potentials assessed by the newly developed signal-averaged vector-projected 187-channel electrocardiogram in patients with old myocardial infarction

Risk stratification of lethal arrhythmias is important for the management of ischemic heart disease. Recently, we developed a novel 187-channel signal-averaged vector-projected high-resolution electrocardiograph (187-ch SAVP-ECG) with a Mason–Likar lead system with 10 electrodes. The purpose of this study was to examine the feasibility of a noninvasive evaluation of the spatial distribution of high-frequency late potentials (HFLPs) in patients with myocardial infarction (MI) by using the 187-ch SAVP-ECG. Sixty-four MI patients (7 women and 57 men), between the age of 39 and 84 years (mean 67.7±9.7 years), with positive ventricular late potentials defined by an X, Y, Z-lead ECG were studied. The integrated ventricular 187-ch SAVP-ECG could identify the area of HFLPs that was projected virtually by mathematically calculated 187 electrograms on the body surface in all patients, and differentiate the locations of MI. The 187-ch SAVP-ECG can be a practical and noninvasive examination tool for identifying the location of infarction areas and possible arrhythmogenic substrates with slow conduction properties in patients with MI.

Signal-averaged and standard electrocardiography in patients with newly diagnosed epilepsy

Antiepileptic drugs (AEDs) have been associated with cardiac conduction abnormalities and arrhythmias, predominantly in patients with predisposing cardiac conditions. Ventricular late potentials (VLPs) detected in the signal-averaged electrocardiogram (SAECG) may imply an increased risk of ventricular tachycardia or fibrillation. Twenty-six AED-naïve patients with newly diagnosed epilepsy and no clinical evidence of heart disease were examined with SAECG and standard ECG. Fifteen patients were treated with lamotrigine and ten with carbamazepine. No significant abnormality was found in the standard ECG or SAECG three to nine months after initiation of AED therapy. In one patient, a VLP was detected at baseline and subsequent MRI demonstrated significant right ventricular pathology; therefore, this patient was excluded from the rest of the study. This exclusion along with only newly diagnosed patients with a low total seizure count being included in the study may explain the lack of AED-induced electrocardiographic abnormalities in this patient cohort.

CLINICAL FEATURES OF VLP IN THE HIGH-ELDERLY ACUTE MYOCARDIAL INFARCTION PATIENTS

ObjectivesTo discuss the positive rate of ventricular late potential (VLP) in the High-elderly group (ages >=80), the elder group (ages >=60) and the non-elderly group AMI patients (ages <60), respectively.Methods357...

CLINICAL FEATURE ANALYSIS OF VENTRICULAR LATE POTENTIAL BETWEEN ACUTE STEMI AND NSTEMI PATIENTS

ObjectivesTo discuss the positive rate of ventricular late potential (VLP) between acute ST-segment elevation myocardial infarction (STEMI) and acute non ST-segment elevation myocardial infarction (NSTEMI) patients.Methods376 cases of acute myocardial...

A New Ventricular Late Potential Classification System Using Ant Colony Optimization

Problem statement: Ventricular Late Potentials (VLPs) are low-level high frequency signals that are usually found within the terminal part of the QRS complex from patients after myocardial infarction. Patients with VLPs are at risk of developing ventricular tachycardia, which is the major cause of death if patients suffering from heart disease. Approach: Discrete Wavelet Transform was used to detect VLPs and then ANT Colony Optimization (ACO) was applied to classify subjects with and without VLPs. Results: A set of Discrete Wavelet Transform (DWT) coefficients was selected from the wavelet decomposition. Three standard parameters of VLPs such as QRST, D40 and V40 were established. After that a novel clustering algorithm based on Ant Colony Optimization was developed for classifying arrhythmia types. Conclusion: The wavelet decomposition enabled us to perform the task efficiently and produced reliable results.

A Method for Ventricular Late Potentials Detection Using Time-Frequency Representation and Wavelet Denoising

This study proposes a method for ventricular late potentials (VLPs) detection using time-frequency representation and wavelet denoising in high-resolution electrocardiography (HRECG). The analysis is performed both with the signal averaged electrocardiography (SAECG) and in real time. A comparison between the temporal and the time-frequency analysis is also reported. In the first analysis the standard parameters QRSd, LAS40, and RMS40 were used; in the second normalized energy in time-frequency domain was calculated. The algorithm was tested adding artificial VLPs to real ECGs.

Relationship between late ventricular potentials and myocardial 123I-metaiodobenzylguanidine scintigraphy in patients with dilated cardiomyopathy with mild to moderate heart failure: results of a prospective study of sudden death events

Late ventricular potentials (LPs) are considered to be useful for identifying patients with heart failure at risk of developing ventricular arrhythmias. (123)I-metaiodobenzylguanidine (MIBG) scintigraphy, which is used to evaluate cardiac sympathetic activity, has demonstrated cardiac sympathetic denervation in patients with malignant ventricular tachyarrhythmias. This study was undertaken to clarify the relationship between LPs and (123)I-MIBG scintigraphy findings in patients with dilated cardiomyopathy (DCM). A total of 56 patients with DCM were divided into an LP-positive group (n = 24) and an LP-negative group (n = 32). During the compensated period, the delayed heart/mediastinum count (H/M) ratio, delayed total defect score (TDS), and washout rate (WR) were determined from (123)I-MIBG images and plasma brain natriuretic peptide (BNP) concentrations were measured. Left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), and left ventricular ejection fraction (LVEF) were simultaneously determined by echocardiography. LVEDV, LVESV, LVEF and plasma BNP concentrations were similar in the two groups. However, TDS was significantly higher (35 ± 8 vs. 28 ± 6, p < 0.005), the H/M ratio was significantly lower (1.57 ± 0.23 vs. 1.78 ± 0.20, p < 0.005), and the WR was significantly higher (60 ± 14% vs. 46 ± 12%, p < 0.001) in the LP-positive than in the LP-negative group. The average follow-up time was 4.5 years, and there were nine sudden deaths among the 56 patients (16.1%). In logistic regression analysis, the incidences of sudden death events were similar in those LP-negative with WR <50%, LP-negative with WR ≥ 50% and LP-positive with WR <50% (0%, 10.0% and 14.3%, respectively), but was significantly higher (41.2%) in those LP-positive with WR ≥ 50% (p < 0.01, p < 0.05, and p < 0.05, respectively). The present study demonstrated that the values of cardiac (123)I-MIBG scintigraphic parameters were worse in LP-positive DCM patients than in LP-negative DCM patients. Furthermore, in LP-positive DCM patients with a high WR, the incidence of sudden death events was higher than that in other subgroups of DCM patients.