Spectral Temporal Mapping Research Articles

ELECTRICAL CARDIAC REMODELING IN MEN WITH ARTERIAL HYPERTENSION AFFECTED BY PSORIASIS VULGARIS

Psoriasis and arterial hypertension are often observed in men of working age. Biologically active molecules such as insulin-like growth factor, vascular endothelial growth factor (VEGF), etc. play a significant role in the pathogenesis of these diseases. These factors contribute to cardiac remodeling, which is one of the arrhythmogenic substrates. The aim of the study was a comprehensive assessment of electrical cardiac parameters in male patients suffering from arterial hypertension affected by psoriasis vulgaris. Materials and Methods. The study was conducted in 2021–2023. It involved 110 male patients undergoing outpatient treatment for stage 2 arterial hypertension. Their average age was 52.4±6.9 years. The patients were divided into 2 groups: Group 1 (comparison) – 50 patients with arterial hypertension; Group 2 (control) – 60 patients with hypertension and psoriasis vulgaris in the progressive moderate severity stage (PASI index between 10 and 20). Results. In males with arterial hypertension affected by psoriasis vulgaris, late ventricular potentials were statistically significantly more common (33 %) compared to those with arterial hypertension without psoriasis (16 %) (χ²=4.32; p=0.048). In patients with both arterial hypertension and psoriasis, a greater number of local peaks in the ventricular complex along all Frank orthogonal leads were registered in spectral-temporal mapping of the QRS complex. Conclusion. The concomitant psoriasis vulgaris in males with arterial hypertension negatively effects the parameters of cardiac electrical remodeling.

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.

Prognostic significance of the signal averaged electrocardiogram in patients with chronic stable coronary artery disease. Analysis in the time domain and by spectral temporal mapping.

Ventricular late potentials detected by the signal averaged electrocardiogram (SAECG) have been used to predict cardiac death in patients after recent myocardial infarction. The goal of this study was to investigate the prognostic significance of the SAECG in a population of chronic coronary artery disease, with and without previous myocardial infarction. SAECG was recorded in 698 patients with angiographically proven coronary artery disease and analyzed by time domain analysis (TDA) and by spectral temporal mapping (STM). Cardiac death or ventricular fibrillation (= cardiac event) were used as the primary endpoint for follow-up (25 to 33 months). A cardiac event occurred in 46 out of 698 patients (6.6%). An abnormal SAECG using TDA was found in 43% of patients with a cardiac event, as compared to 21.7% in those without (p<0.0005). The probability of a cardiac event during follow-up was 4.4% when TDA and STM were both normal, 9.5% and 10.2% when either STM or TDA were abnormal and 28.5% when both were abnormal. A duration of the averaged QRS complex of more than 120 ms and a left ventricular ejection fraction of less than 45% were the only independent predictors of a cardiac event. Logistic regression analysis could predict a cardiac event with a sensitivity of 54% and a specificity of 88%. In patients with chronic coronary artery disease the duration of the signal averaged QRS complex and left ventricular ejection fraction are independent predictors of cardiac death or ventricular fibrillation.

Reproducibility of time-domain and three different frequency-domain techniques for the analysis of the signal-averaged electrocardiogram

Because time-domain (TD) analysis of the signal-averaged ECG (SAECG) has some limitations that limit its use, several frequency-domain analysis techniques were developed in an attempt to improve the dignostic ability of the SAECG. However, it is not known how reliable these techniques are at detecting late potentials. This prospective study compares the short-term reproducibility of 4 analysis techniques: TD analysis, spectral temporal mapping (STM), spectral turbulence analysis (STA), and acceleration spectrum analysis (ASA), in a large series of normal patients and post-myocardial infarction (MI) patients. Two consecutive SAECGs were recorded in 634 patients that were divided into 3 groups: 117 remote MI patients undergoing programmed electrical stimulation for the inducibility of ventricular tachycardia (Group 1), 407 consecutive acute MI survivors (Group 2), and in 110 healthy volunteers (Group 3). The diagnostic reproducibility of the 4 techniques was evaluated by comparing rates of inconsistent results (1 normal and the other abnormal). The numeric reproducibility for each technique was assessed by comparing the normalized differences of each single SAEGG parameter between the 2 recordings. inconsistent results of diagnostic reproducibility were observed in 4.1%, 6.9%, 9.8%, and 18.0%, with TD, STA, ASA, and STM, respectively. Comparisons of these rates were significantly different (P<.05) except between STA and ASA (P=.07). The numeric reproducibility was highes for TD parameters, lowest for STM factors of normality, and intermediate for STA and ASA indices. TD analysis remains the most reproducible SAECG analysis technique, whereas STM showed the worst reproducibility, which limits its clinical applicability. STA and ASA provide an acceptable intermediate reproducibility, the former being slightly, although not significantly, more reproducible than the latter.

Improved predictive ability of combined time domain analysis and spectral temporal mapping of the signal-averaged electrocardiogram in patients with ischemic cardiomyopathy

Improved predictive ability of combined time domain analysis and spectral temporal mapping of the signal-averaged electrocardiogram in patients with ischemic cardiomyopathy

Spectral temporal mapping in patients with life threatening arrhythmias

Spectral temporal mapping in patients with life threatening arrhythmias

Short-term reproducibility of time domain, spectral temporal mapping, and spectral turbulence analysis of the signal-averaged electrocardiogram in normal subjects and patients with acute myocardial infarction

The aim of this prospective study was to compare the short-term reproducibility of the signal-averaged ECG (SAECG) with three analysis techniques, conventional time-domain analysis, spectral-temporal mapping (STM), and spectral-turbulence analysis (STA), in a large series of normal subjects and patients with acute myocardial infarction (AMI). Two consecutive SAECGs were recorded in 225 consecutive patients 10.2 ± 2.7 days after AMI and in 85 healthy volunteers. The visual, diagnostic, and quantitative reproducibility of the three techniques was compared. Time-domain analysis was the most reproducible method, having high R 2 correlations, statistically fewer inconsistent diagnostic recordings, and statistically smaller differences compared with other techniques. STM was the least reproducible, justifying caution in its current form. Although STA was significantly less reproducible than time-domain analysis, it was also significantly better than STM. Two STA parameters, spectral entropy and interslice correlation mean, showed good reproducibility, suggesting that modification of this analysis technique could be useful in risk stratification.

The time course and relation of positive signal-averaged electrocardiograms by time-domain and spectral temporal mapping analyses after infarction

We evaluated the time course of development of positive signal-averaged electrocardiograms (SA-ECGs) by time-domain and Spectral Temporal Mapping ™ (STM) analyses after myocardial infarction in 88 patients without bundle branch block. The incidence of positive SA-ECGs by time-domain analysis peaked at 4 to 8 weeks postinfarction whereas the peak incidence by STM analysis varied from 4 days to 4 to 10 months postinfarction. Positive time-domain SA-ECGs demonstrated a significantly reduced factor of normality (NF) compared with negative time-domain SA-ECGs by X, Z, or vector STM analyses, but marked overlap was present for the standard deviations of positive and negative SA-ECGs in all STM leads. Chi square analysis demonstrated a significant correlation only between X-lead STM analysis and time-domain analysis; however, the two methods were markedly discordant. Although there is a statistically significant relation between time-domain and STM analyses of SA-ECGs, the two analyses are not clinically interchangeable.

Usefulness of signal-averaged electrocardiogram in idiopathic dilated cardiomyopathy for identifying patients with ventricular arrhythmias

In idiopathic dilated cardiomyopathy (IDC), the relation between the signal-averaged electrocardiogram and ventricular tachycardia (VT) remains unclear. In this study, conventional time domain and frequency domain analyses (2-dimensional, spectral temporal mapping and spectral turbulence analysis) of the signal-averaged electrocardiogram were performed in 64 patients with IDC. Eight patients had a history of symptomatic sustained VT and an additional 24 had nonsustained VT recorded during ambulatory electrocardiography. Conventional time domain analysis, using the 25 and 40 Hz filter, and spectral temporal mapping, detected late potentials within the terminal QRS in 8 (13%), 14 (22%) and 18 (28%) patients, respectively. Late potentials were seen more often in patients with than without VT, and in patients with sustained versus nonsustained VT, but these differences were not significant. The predictive accuracy of these techniques in detecting either form of VT were: sensitivity, 22, 25 and 31%; specificity, 97, 81 and 75%; and overall predictive value, 59, 53 and 50%, respectively. Two-dimensional frequency domain analysis of the signal-averaged electrocardiogram revealed a higher energy and area ratio in patients with than without VT (entire QRS), and in patients with sustained versus nonsustained VT (entire QRS and terminal QRS). Spectral turbulence analysis was abnormal in 24 patients (39%), but no differences were observed between patients with and without VT. During follow-up (mean duration 18 ± 14 months), 5 patients had arrhythmic events (3 died suddenly, 1 had aborted sudden death and 1 developed sustained VT). The signal-averaged electrocardiogram was abnormal in 1 patient using time domain analysis and spectral temporal mapping, and in 3 using spectral turbulence analysis (score = 4). In conclusion, time domain and spectral temporal mapping analysis of the signal-averaged electrocardiogram identifies IDC patients with VT with high specificity but low sensitivity. The application of the 2-dimensional frequency analysis improves identification of patients with sustained VT. Spectral turbulence analysis of the entire QRS complex is a promising technique for the identification of patients with IDC at high risk of sudden death.

The value of time and frequency domain, and spectral temporal mapping analysis of the signal-averaged electrocardiogram in identification of patients with hypertrophic cardiomyopathy at increased risk of sudden death.

Late potentials detected by the signal-averaged ECG (SAECG) identify post-infarction patients at risk from sustained ventricular tachycardia (VT) and sudden death. Hypertrophic cardiomyopathy (HCM) is also associated with increased risk of sudden death. In adults, episodes of non-sustained VT on ambulatory ECG monitoring are a marker of high risk patients. In children and adolescents, however, there is no reliable ECG marker, and clinical features have low predictive accuracy. The prognostic value of the SAECG in HCM has not been systematically evaluated. We examined the relation of detailed time domain, frequency domain, and spectral temporal mapping analysis of the SAECG and clinical and echocardiographic features, and the results of 48 h ambulatory ECG monitoring in 121 consecutive patients with HCM. Non-sustained VT on Holter monitoring was recorded in 27 (23%) patients. An abnormal time domain SAECG was present in three (11%) patients with VT vs three (3%) without VT (ns). Of the SAECG variables, reduced (below 150 microV) voltage of the initial 40 ms of the signal-averaged QRS complex was the best predictor for non-sustained VT (sensitivity: 95%; specificity: 74%: positive predictive accuracy: 64%; negative predictive accuracy: 97%). Nine patients (of whom eight were < or = 30 years of age) experienced catastrophic events: three died suddenly and six had been resuscitated from out-of-hospital ventricular fibrillation. None of them had an abnormal time domain SAECG. The frequency domain analysis and spectral temporal mapping of the SAECG did not improve the identification of patients with VT or patients with catastrophic events. In conclusion, alterations of the initial portion of the signal-averaged QRS complex identified patients with HCM and non-sustained VT, but the SAECG was not useful in identifying young patients who suffered cardiac arrest.

Effects of procainamide on the signal-averaged electrocardiogram in relation to the results of programmed ventricular stimulation in patients with sustained monomorphic ventricular tachycardia

Objectives. The aim of this study was to assess the ability of the signal-averaged electrocardiogram (ECG) to predict the efficacy of procainamide.Background. The main role of the signal-averaged ECG has been the identification of postinfarction patients at risk of sudden death. Prediction of the efficacy of antiarrhythmic drugs represents another potential clinical application of this technique.Methods. The study examined the effects of procainamide on the time domain and spectral temporal analysis of the signalaveraged ECG in relation to the results of programmed ventricular stimulation studies in 31 patients with inducible sustained monomorphic ventricular tachycardia.Results. Procainamide significantly prolonged the total and the initial QRS complex and low amplitude signal durations (mean ± SD135 ± 30 vs. 161 ± 46 ms, p < 0.0001; 87 ± 16 vs. 98 ± 20 ms, p < 0.0001, and 48 ± 23 vs. 63 ± 36 ms, p < 0.001, respectively) whereas the root-mean-square voltage of the total QRS complex and of the last 40 ms of the QRS complex was significantly reduced (mean ± SD 112 ± 36 vs. 87 ± 36 μV, p < 0.0001; 21 ± 19 vs. 13 ± 12 μV, p < 0.002, respectively). The results of spectral temporal mapping of the signal-averaged ECG were similar before and after procainamide administration. Procainamide prevented the inducibility of sustained ventricular tachycardia or prolonged the cycle length of ventricular tachycardia by ≥100 ms in 16 patients (52%) (responders). The fractional prolongation of the total QRS duration was significantly greater in responders (26 ± 15%) than in nonresponders (10 ± 10%) (p < 0.002) and, when this prolongation was ≥15%, identified responders with a sensitivity of 94%, a specificity of 87% and an overall predictive accuracy of 90%.Conclusions. The effects of procainamide on inducibility of ventricular tachycardia during programmed ventricular stimulation can be predicted by the degree of drug-induced prolongation of the signal-averaged QRS complex.

Improved identification of late potentials by adjustment of the number of analyzed segments of the spectral temporal mapping of the signal-averaged electrocardiogram

Late potentials (LP), microvolt oscillations occurring at the end and after the QRS complex, identify patients at risk of ventricular tachycardia and sudden death. 1,2 They can be detected by the time domain analysis of the surface signal-averaged electrocardiogram (SAECG). 1 LP can also be identified by the frequency domain analysis of the SAECG because they are characterized by higher frequencies than the ST segment. 3 This technique offers some advantages over time domain analysis: patients with bundle branch block need not be excluded, a noise-dependent algorithm for detection of LP offset is not applied, and high-pass filters, distorting the signal, are not used. Spectral temporal mapping (STM) of the SAECG is a new frequency domain technique that uses fast Fourier transform analysis. 4 Routinely, 25 electrocardiographic segments are analyzed, first starting 20 ms before the standard QRS offset. The frequency content in the most distal 5 segments, which are located well within the ST segment (where LP are not likely to be) is used as a reference spectrum, and compared with the spectra of earlier segments (where LP are often present) in order to calculate the result of the STM. It is crucial for correct analysis to avoid the presence of high frequency components in the last 5 reference segments. However, when the total QRS duration exceeds the standard QRS duration by >20 ms owing to the presence of a long LP, the reference segments include LP (Figure 1A). Therefore, a new formula is needed to calculate the number of segments to be analyzed in such patients.

Prediction of antiarrhythmic efficacy of class I and III agents in patients with ventricular tachycardia by signal-averaged ECG analysis.

The effects of procainamide and dofetilide (pure Class III antiarrhythmic agent) on the signal-averaged ECG (SAECG) were examined in relation to the results of programmed ventricular stimulation studies in 25 patients with inducible sustained monomorphic ventricular tachycardia. Procainamide prolonged significantly the total QRS and low amplitude signal durations (140 +/- 31 msec vs 166 +/- 48 msec, P < 0.0001; 50 +/- 25 msec vs 65 +/- 38 msec, P < 0.002, respectively) whereas the root mean square voltage of the last 40 msec of the QRS complex was significantly reduced (22 +/- 21 microV vs 13 +/- 12 microV, P < 0.006). Procainamide was effective (prevention of the inducibility of sustained ventricular tachycardia or prolongation of the cycle length of ventricular tachycardia by > 100 msec) in 15 of 27 drug trials. Of the procainamide induced SAECG changes, the fractional prolongation of the total QRS duration was the best parameter that identified effectively treated patients (24% +/- 16% in responders vs 10% +/- 11% in nonresponders, P < 0.014). A fractional prolongation of the total QRS duration by > 15% identified effectively treated patients with a sensitivity of 87%, specificity of 81%, and an overall predictive accuracy of 84%. Dofetilide did not change the SAECG, and no SAECG parameter predicted the results of programmed ventricular stimulation. The effects of both drugs on the spectral analysis (area ratios) and on the spectral temporal mapping (the values of normality factor) of the SAECG were not consistent. In conclusion, antiarrhythmic efficacy of procainamide can be predicted by the degree of drug induced prolongation of the signal-averaged QRS complex.(ABSTRACT TRUNCATED AT 250 WORDS)

Autonomic manipulation influences both temporal and frequency analyses of late potentials.

Previous studies of late potentials have not standardized the autonomic milieu at the time of testing. We studied the effects of autonomic manipulation in seven patients with previous Q wave myocardial infarction. Late potentials were evaluated using standard temporal (TD) and spectral temporal mapping techniques (STM) in the drug free state, and during separate intravenous administration of each of the following: isoproterenol, esmolol, and atropine. Isoproterenol was titrated to achieve a heart rate of 130% of baseline. Esmolol was infused at a rate of 250 micrograms/kg per minute, after a loading dose of 500 micrograms/kg. Atropine was given as a 2-mg bolus. In addition, five patients who received no drug infusions acted as controls, undergoing four serial signal-averaging studies in the baseline state: a "baseline" study, and then three additional studies at time intervals similar to those incurred by the study patients. Therefore, a total of 21 TD and 21 STM tests were done in the study group (seven patients; three drugs per patient) during the drug infusions, and 15 TD and 15 STM tests were done in the control group (five patients; three "nonbaseline" tests per patient). A change (normal to abnormal, or vice versa) in TD during a drug infusion occurred in 24% of the tests. No such change occurred in the control group (P < 0.01). A change in STM during a drug infusion occurred in 38% of tests, versus 13% of tests in the control group (P = 0.14). Overall, six of seven patients had a change in TD and/or STM diagnosis with infusion of one or more of the study drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

Frequency versus time domain analysis of signal-averaged electrocardiograms. I. Reproducibility of the results

Three repeated signal-averaged electrocardiographic (ECG) recordings were made in 40 subjects (15 healthy volunteers. 10 patients with ventricular tachycardia without apparent heart disease and 15 patients with ventricular tachycardia after myocardial infarction). In each subject, the three recordings were made within 25 min. The recordings were subsequently analyzed by 1) the conventional time domain method of signal-averaged ECG analysis with use of filter settings of 25 to 250 Hz and 40 to 250 Hz, 2) a spectral analysis method computing the energy area within the spectral boundaries of 40 to 140 Hz and the ratio between the energies of areas within the boundaries 40 to 140 Hz and 0 to 40 Hz, and 3) spectral temporal mapping computing the “normality factor.”The study compared the reproducibility of these three approaches to the analysis of signal-averaged ECGs. First, the reproducibility of the diagnostic conclusions (that is, of the diagnosis of late potentials) was compared for the time domain method and for spectral temporal mapping. Second, the reproducibility of the numeric values of individual indexes provided by different methods was compared for all methods by computing the ratios between standard deviations of measurements in individual patients and standard deviation of all measurements.The reproducibility of diagnostic conclusions was significantly higher for the time domain method than for spectral temporal mapping (p < 0.05, sign test). The numeric reproducibility of the normality factors produced by spectral temporal mapping was significantly lower than the numeric reproducibility of the values of all indexes provided by time domain, spectral area and spectral area ratio methods (p < 0.05 to 0.00005, Wilcoxon tests). Spectral temporal mapping was the least reproducible method for the analysis of signal-averaged ECGs.

Frequency versus time domain analysis of signal-averaged electrocardiograms. II. Identification of patients with ventricular tachycardia after myocardial infarction

Late potentials detected by the time domain signal-averaged electrocardiogram (ECG) are a well established marker for ventricular tachycardia in patients after a myocardial infarction, but the value of frequency domain analysis of the signal-averaged ECG in identifying these patients remains controversial. This study compared the results of time domain, frequency domain and spectral temporal mapping analyses of the signal-averaged ECG in 30 postinfarction patients with spontaneous sustained ventricular tachycardia and in 30 postinfarction patients without ventricular tachycardia matched for age, gender and infarct site. No patient with bundle branch block was included.Time domain signal-averaged ECG indexes were significantly different in patients with and without ventricular tachycardia (p < 0.001). Frequency domain results were not consistently different between these groups. The values of the normality factor of spectral temporal mapping were significantly lower in patients with ventricular tachycardia (p < 0.04). Results of the time domain signal-averaged ECG were abnormal in 22 patients with ventricular tachycardia (73%) but in only 3 control patients (10%) (p < 0.001). Spectral temporal mapping results were abnormal in 21 patients with ventricular tachycardia (70%) compared with 12 control patients (40%) (p < 0.04). When the optimal numeric values of dichotomy points were computed for patient stratification at different sensitivity levels, time domain analysis identified patients with ventricular tachycardia with significantly fewer false positive results than were obtained with either frequency analysis or spectral temporal mapping.It is concluded that frequency domain analysis and spectral temporal mapping of the signal-averaged ECG did not improve the identification of postinfarction patients with ventricular tachycardia and without bundle branch block.

Identification of Post Infarction Patients with Ventricular Tachycardia. Comparison of the Time Domain, Frequency Domain, and Spectral Temporal Mapping of the Signal-Averaged Electrocardiogram

Identification of Post Infarction Patients with Ventricular Tachycardia. Comparison of the Time Domain, Frequency Domain, and Spectral Temporal Mapping of the Signal-Averaged Electrocardiogram

The Influence of the Infarction site on Identification of Post Infarction Patients with Ventricular Tachycardia Based on Spectral Temporal Mapping of Signal-Averaged Electrocardiogram

The Influence of the Infarction site on Identification of Post Infarction Patients with Ventricular Tachycardia Based on Spectral Temporal Mapping of Signal-Averaged Electrocardiogram

Correct Identification of late Potentials by Spectral Temporal Mapping of Signal-Averaged Electrocardiogram in post Infarction Patients with Ventricular Tachycardia

Correct Identification of late Potentials by Spectral Temporal Mapping of Signal-Averaged Electrocardiogram in post Infarction Patients with Ventricular Tachycardia

Critical noise level reduction for correct identification of late potentials: An illustrative case report

The precision of detection of late potentials (LPs) on signal-averaged electrocardiography (SAECG) depends on the degree of noise reduction. The recommended low-noise endpoint is 0.3 microV. We describe a patient with sustained ventricular tachycardia after myocardial infarction with very low amplitude LPs in whom a noise level lower than 0.3 microV was necessary in order to obtain an abnormal result of the SAECG. The presence of LPs was confirmed by spectral temporal mapping of the SAECG.