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Marek Malik - One of the best experts on this subject based on the ideXlab platform.
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Predictive value of wavelet decomposition of the Signal-Averaged Electrocardiogram in idiopathic dilated cardiomyopathy.
European heart journal, 2000Co-Authors: Katerina Hnatkova, Niall G. Mahon, P. J. Keeling, Michael Reardon, A. J. Camm, Marek MalikAbstract:Background Wavelet decomposition of the Signal-Averaged Electrocardiogram has been proposed as a method of detecting small and transient irregularities hidden within the QRS complex and of overcoming some of the limitations of time domain analysis of the Signal-Averaged Electrocardiogram. Aim This study evaluated the potential utility of wavelet decomposition analysis in the risk stratification of patients with idiopathic dilated cardiomyopathy. Methods and Results Both wavelet decomposition and time domain analysis were applied to the Signal-Averaged Electrocardiogram recordings of 82 patients with idiopathic dilated cardiomyopathy (mean age 43±14 years, 60 men) and 72 normal controls (mean age 44±15 years, 48 men). Three conventional time domain indices and four wavelet decomposition analysis parameters (QRS length, maximum count, surface area, and relative length) were derived from each recording using a Del Mar CEWS system and an in-house software package, respectively. The results showed that (1) more patients with idiopathic dilated cardiomyopathy than without had late potentials, and that the filtered QRS duration was significantly longer in patients than in controls ( P
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Predictive value of wavelet decomposition of the Signal-Averaged Electrocardiogram in idiopathic dilated cardiomyopathy.
European heart journal, 2000Co-Authors: Katerina Hnatkova, Niall G. Mahon, P. J. Keeling, Michael Reardon, A. J. Camm, Marek MalikAbstract:Wavelet decomposition of the Signal-Averaged Electrocardiogram has been proposed as a method of detecting small and transient irregularities hidden within the QRS complex and of overcoming some of the limitations of time domain analysis of the Signal-Averaged Electrocardiogram. This study evaluated the potential utility of wavelet decomposition analysis in the risk stratification of patients with idiopathic dilated cardiomyopathy. Both wavelet decomposition and time domain analysis were applied to the Signal-Averaged Electrocardiogram recordings of 82 patients with idiopathic dilated cardiomyopathy (mean age 43 +/- 14 years, 60 men) and 72 normal controls (mean age 44 +/- 15 years, 48 men). Three conventional time domain indices and four wavelet decomposition analysis parameters (QRS length, maximum count, surface area, and relative length) were derived from each recording using a Del Mar CEWS system and an in-house software package, respectively. The results showed that (1) more patients with idiopathic dilated cardiomyopathy than without had late potentials, and that the filtered QRS duration was significantly longer in patients than in controls (P<0.001). Similarly, abnormal wavelet decomposition analysis was more common in patients and wavelet decomposition measurements were significantly different between patients and controls (P<0.01); (2) conventional time domain analysis did not distinguish between clinically stable patients and patients who developed progressive heart failure, or between patients with and without arrhythmic events; (3) wavelet decomposition analysis identified patients who went on to develop progressive heart failure but failed to distinguish patients with arrhythmic events from those without; (4) survival analyses of a mean follow-up of 23 months showed that patients with late potentials tended to develop progressive heart failure more frequently than others (P=0.06). Patients with an abnormal wavelet decomposition result more frequently developed progressive heart failure than those with a normal wavelet decomposition result (P=0.027); (5) in a univariate analysis (Cox model), wavelet decomposition measurements but not time domain indices significantly correlated with the development of progressive heart failure (P=0.01). Multivariate analysis showed that only left ventricular end-diastolic dimension and peak oxygen consumption during exercise remained significant predictors of progressive heart failure. Wavelet decomposition analysis of the Signal-Averaged Electrocardiogram is superior to conventional time domain analysis for identifying patients with idiopathic dilated cardiomyopathy at increased risk of clinical deterioration. Wavelet decomposition analysis, however, is unlikely to prospectively distinguish patients at a high risk of arrhythmic events in idiopathic dilated cardiomyopathy in its present form.
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Short-, mid-, and long-term reproducibility of the atrial Signal-Averaged Electrocardiogram in healthy subjects: comparison with the conventional ventricular Signal-Averaged Electrocardiogram.
Pacing and clinical electrophysiology : PACE, 2000Co-Authors: Irina Savelieva, Katerina Hnatkova, A. J. Camm, Kudret Aytemir, Marek MalikAbstract:Although atrial Signal-Averaged Electrocardiogram (SAECG) has been proposed for noninvasive identification of patients with atrial tachyarrhythmias, the substantial variability of the measurement limits the clinical value. The aim of the study was to assess the short- to long-term reproducibility of atrial SAECG and to compare it to that of the conventional ventricular SAECG in 51 healthy volunteers (30 men; age 32 +/- 8 years). In each subject, SAECG recordings were obtained using MAC-VU electrocardiograph and HiRES and PHiRES software (Marquette Medical Systems) and repeated after 5 minutes, 1 day, 1 week, and 1 month. Automatically detected onset and offset of the filtered QRS complex and P wave were subsequently corrected by two independent observers, and the averaged values were used for the analysis. Conventional ventricular SAECG parameters: filtered QRS duration (QRStot), low amplitude signal duration, and root mean square voltage (RMS) of the terminal 40 ms of QRS, and 5 atrial parameters: filtered P wave duration (Ptot), RMS of the terminal 40, 30, 20 ms, and of the entire P wave were obtained. Relative errors of different pairs of measures were used to assess the intrasubject reproducibility. QRStot and Ptot were the most reproducible parameters. The relative errors after 5 minutes, 1 day, 1 week, and 1 month were 0.8% to 2.4% for QRStot, and 1.3% to 4.2% for Ptot. For RMS voltages, the relative errors exceeded 15% in short-term and 20% in long-term recordings. Although Ptot was statistically less reproducible than QRStot, the reproducibility of the former was good and comparable to that of the QRStot. The reproducibility of the voltage parameters was significantly poorer than that of the duration parameters. The study showed a satisfactory short- and long-term reproducibility of Ptot in the atrial SAECG in healthy subjects. However, low reproducibility of the voltage parameters should be considered in clinical applications.
Edward B. Caref - One of the best experts on this subject based on the ideXlab platform.
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Improved diagnostic value of combined time and frequency domain analysis of the Signal-Averaged Electrocardiogram after myocardial infarction
Journal of the American College of Cardiology, 1999Co-Authors: Rafael Vázquez, Edward B. Caref, Francisco Torres, Margarita Reina, Aurora Espina, Nabil El-sherifAbstract:Abstract Background Time domain analysis (TD) of the Signal-Averaged Electrocardiogram (SAECG) presents a higher incidence of false positives in inferior myocardial infarction (MI), whereas spectral turbulence analysis (STA) suffers from a higher incidence of false positives in anterior MI. We investigated the hypothesis that a combined TD and STA (TD+STA) analysis of the SAECG could improve its predictive accuracy for major arrhythmic events (MAE) after MI. Methods Signal-Averaged Electrocardiograms were prospectively recorded 10.1 ± 2.6 days after acute MI in 602 patients. Time domain analysis and STA were performed using standard parameters and criteria for abnormality. For the combined TD+STA model, stepwise discriminant analysis was utilized to optimize prediction of MAE. Receiver operating characteristic curves were utilized to optimize cutoff values for each SAECG parameter separately, and also for the combined TD+STA model. Results During a one-year follow-up period, 38 patients had MAE: 14 sustained ventricular tachycardia, 2 resuscitated ventricular fibrillation and 22 sudden cardiac deaths. The total predictive accuracy of combined TD+STA (89.9%) was significantly higher than TD (75.1%) or STA (77.6%). The negative predictive accuracy of all three analyses was high (98%). The positive predictive accuracy of TD (19.6%) or STA (18.3%) was quite low, and significantly improved to 35.8% by combined TD+STA analysis. The positive predictive accuracy of TD+STA improved to 51.2% in patients with left ventricular ejection fraction Conclusions Combined TD+STA analysis of the SAECG significantly improves its prognostic ability for MAE in post-MI patients compared with TD or STA analyzed separately.
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risk stratification for arrhythmic events in patients with nonischemic dilated cardiomyopathy and nonsustained ventricular tachycardia role of programmed ventricular stimulation and the signal averaged Electrocardiogram
Journal of the American College of Cardiology, 1994Co-Authors: Gioia Turitto, Edward B. Caref, Ratan K Ahuja, Nabil ElsherifAbstract:Abstract Objectives . This study investigated prediction of arrhythmic events by the Signal-Averaged Electrocardiogram (ECG) and programmed stimulation in patients with nonischemic dilated cardiomyopathy. Background . Risk stratification in patients with nonischemic dilated cardiomyopathy remains controversial. Methods . Eighty patients with nonischemic dilated cardiomyopathy and spontaneous nonsustained ventricular tachycardia underwent Signal-Averaged electrocardiography (both time-domain and spectral turbulence analysis) and programmed stimulation. All patients were followed up for a mean of 22 ± 26 months. Results . Sustained monomorphic ventricular tachycardia was induced in 10 patients (13%), who all received amiodarone. The remaining 70 patients were followed up without antiarrhythmic therapy. Of the 80 patients, 15% had abnormal findings on the time-domain Signal-Averaged ECG, and 39% had abnormal findings on spectral turbulence analysis. Time-domain Signal-Averaged electrocardiography had a better predictive accuracy for induced ventricular tachycardia than spectral turbulence analysis (88% vs. 66%, p Conclusions . In patients with nonischemic dilated cardiomyopathy, 1) there is a strong correlation between abnormal findings on the time-domain Signal-Averaged ECG and induced ventricular tachycardia, but both findings are uncommon; and 2) normal findings on the Signal-Averaged ECG, as well as failure to induce ventricular tachycardia, do not imply a benign outcome.
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Spontaneous myocardial ischemia and the Signal-Averaged Electrocardiogram
The American journal of cardiology, 1991Co-Authors: Gioia Turitto, Edward B. Caref, Egidio Zanchi, Fabio Menghini, George Kelen, Nabil El-sherifAbstract:Abstract The effects of transient myocardial ischemia on the Signal-Averaged Electrocardiogram were investigated in 13 patients with coronary artery disease and spontaneous angina undergoing 3-channel ambulatory electrocardiography. Ischemia was seen as ST elevation in 2 patients or ST depression in 11; it was anterior in 5 patients, inferior in 4 and undefined in 4. Signal-Averaged Electrocardiograms with noise levels ≤1 μV were obtained from Holter tapes during 54 of 61 ischemic attacks recorded in the study group (88%), and compared with 54 tracings recorded within 60 minutes of the index attacks. Baseline tracings were normal in 8 patients (62%), showed a long QRS duration in 2 (15%), and both a long QRS duration and a late potential in the remaining 3 (23%). Comparison of recordings at baseline and during ischemic attacks revealed no significant changes in Signal-Averaged electrocardiographic parameters. Absence of significant differences was also noted when analysis was performed according to the type of ischemic attacks (associated with ST elevation [n = 14] or ST depression [n = 40]), their location (anterior [n = 21] or inferior [n = 23]), their duration (>10 minutes [n = 29] or ≤10 minutes [n = 25]), and their magnitude (>2 mm [n = 18] or ≤2 mm [n = 36]). It is concluded that spontaneous transient myocardial ischemia, independent of its type, location, duration and magnitude, does not generate a substrate for late potentials on the Signal-Averaged Electrocardiogram.
Gioia Turitto - One of the best experts on this subject based on the ideXlab platform.
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risk stratification for arrhythmic events in patients with nonischemic dilated cardiomyopathy and nonsustained ventricular tachycardia role of programmed ventricular stimulation and the signal averaged Electrocardiogram
Journal of the American College of Cardiology, 1994Co-Authors: Gioia Turitto, Edward B. Caref, Ratan K Ahuja, Nabil ElsherifAbstract:Abstract Objectives . This study investigated prediction of arrhythmic events by the Signal-Averaged Electrocardiogram (ECG) and programmed stimulation in patients with nonischemic dilated cardiomyopathy. Background . Risk stratification in patients with nonischemic dilated cardiomyopathy remains controversial. Methods . Eighty patients with nonischemic dilated cardiomyopathy and spontaneous nonsustained ventricular tachycardia underwent Signal-Averaged electrocardiography (both time-domain and spectral turbulence analysis) and programmed stimulation. All patients were followed up for a mean of 22 ± 26 months. Results . Sustained monomorphic ventricular tachycardia was induced in 10 patients (13%), who all received amiodarone. The remaining 70 patients were followed up without antiarrhythmic therapy. Of the 80 patients, 15% had abnormal findings on the time-domain Signal-Averaged ECG, and 39% had abnormal findings on spectral turbulence analysis. Time-domain Signal-Averaged electrocardiography had a better predictive accuracy for induced ventricular tachycardia than spectral turbulence analysis (88% vs. 66%, p Conclusions . In patients with nonischemic dilated cardiomyopathy, 1) there is a strong correlation between abnormal findings on the time-domain Signal-Averaged ECG and induced ventricular tachycardia, but both findings are uncommon; and 2) normal findings on the Signal-Averaged ECG, as well as failure to induce ventricular tachycardia, do not imply a benign outcome.
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Spontaneous myocardial ischemia and the Signal-Averaged Electrocardiogram
The American journal of cardiology, 1991Co-Authors: Gioia Turitto, Edward B. Caref, Egidio Zanchi, Fabio Menghini, George Kelen, Nabil El-sherifAbstract:Abstract The effects of transient myocardial ischemia on the Signal-Averaged Electrocardiogram were investigated in 13 patients with coronary artery disease and spontaneous angina undergoing 3-channel ambulatory electrocardiography. Ischemia was seen as ST elevation in 2 patients or ST depression in 11; it was anterior in 5 patients, inferior in 4 and undefined in 4. Signal-Averaged Electrocardiograms with noise levels ≤1 μV were obtained from Holter tapes during 54 of 61 ischemic attacks recorded in the study group (88%), and compared with 54 tracings recorded within 60 minutes of the index attacks. Baseline tracings were normal in 8 patients (62%), showed a long QRS duration in 2 (15%), and both a long QRS duration and a late potential in the remaining 3 (23%). Comparison of recordings at baseline and during ischemic attacks revealed no significant changes in Signal-Averaged electrocardiographic parameters. Absence of significant differences was also noted when analysis was performed according to the type of ischemic attacks (associated with ST elevation [n = 14] or ST depression [n = 40]), their location (anterior [n = 21] or inferior [n = 23]), their duration (>10 minutes [n = 29] or ≤10 minutes [n = 25]), and their magnitude (>2 mm [n = 18] or ≤2 mm [n = 36]). It is concluded that spontaneous transient myocardial ischemia, independent of its type, location, duration and magnitude, does not generate a substrate for late potentials on the Signal-Averaged Electrocardiogram.
Katerina Hnatkova - One of the best experts on this subject based on the ideXlab platform.
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Predictive value of wavelet decomposition of the Signal-Averaged Electrocardiogram in idiopathic dilated cardiomyopathy.
European heart journal, 2000Co-Authors: Katerina Hnatkova, Niall G. Mahon, P. J. Keeling, Michael Reardon, A. J. Camm, Marek MalikAbstract:Background Wavelet decomposition of the Signal-Averaged Electrocardiogram has been proposed as a method of detecting small and transient irregularities hidden within the QRS complex and of overcoming some of the limitations of time domain analysis of the Signal-Averaged Electrocardiogram. Aim This study evaluated the potential utility of wavelet decomposition analysis in the risk stratification of patients with idiopathic dilated cardiomyopathy. Methods and Results Both wavelet decomposition and time domain analysis were applied to the Signal-Averaged Electrocardiogram recordings of 82 patients with idiopathic dilated cardiomyopathy (mean age 43±14 years, 60 men) and 72 normal controls (mean age 44±15 years, 48 men). Three conventional time domain indices and four wavelet decomposition analysis parameters (QRS length, maximum count, surface area, and relative length) were derived from each recording using a Del Mar CEWS system and an in-house software package, respectively. The results showed that (1) more patients with idiopathic dilated cardiomyopathy than without had late potentials, and that the filtered QRS duration was significantly longer in patients than in controls ( P
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Predictive value of wavelet decomposition of the Signal-Averaged Electrocardiogram in idiopathic dilated cardiomyopathy.
European heart journal, 2000Co-Authors: Katerina Hnatkova, Niall G. Mahon, P. J. Keeling, Michael Reardon, A. J. Camm, Marek MalikAbstract:Wavelet decomposition of the Signal-Averaged Electrocardiogram has been proposed as a method of detecting small and transient irregularities hidden within the QRS complex and of overcoming some of the limitations of time domain analysis of the Signal-Averaged Electrocardiogram. This study evaluated the potential utility of wavelet decomposition analysis in the risk stratification of patients with idiopathic dilated cardiomyopathy. Both wavelet decomposition and time domain analysis were applied to the Signal-Averaged Electrocardiogram recordings of 82 patients with idiopathic dilated cardiomyopathy (mean age 43 +/- 14 years, 60 men) and 72 normal controls (mean age 44 +/- 15 years, 48 men). Three conventional time domain indices and four wavelet decomposition analysis parameters (QRS length, maximum count, surface area, and relative length) were derived from each recording using a Del Mar CEWS system and an in-house software package, respectively. The results showed that (1) more patients with idiopathic dilated cardiomyopathy than without had late potentials, and that the filtered QRS duration was significantly longer in patients than in controls (P<0.001). Similarly, abnormal wavelet decomposition analysis was more common in patients and wavelet decomposition measurements were significantly different between patients and controls (P<0.01); (2) conventional time domain analysis did not distinguish between clinically stable patients and patients who developed progressive heart failure, or between patients with and without arrhythmic events; (3) wavelet decomposition analysis identified patients who went on to develop progressive heart failure but failed to distinguish patients with arrhythmic events from those without; (4) survival analyses of a mean follow-up of 23 months showed that patients with late potentials tended to develop progressive heart failure more frequently than others (P=0.06). Patients with an abnormal wavelet decomposition result more frequently developed progressive heart failure than those with a normal wavelet decomposition result (P=0.027); (5) in a univariate analysis (Cox model), wavelet decomposition measurements but not time domain indices significantly correlated with the development of progressive heart failure (P=0.01). Multivariate analysis showed that only left ventricular end-diastolic dimension and peak oxygen consumption during exercise remained significant predictors of progressive heart failure. Wavelet decomposition analysis of the Signal-Averaged Electrocardiogram is superior to conventional time domain analysis for identifying patients with idiopathic dilated cardiomyopathy at increased risk of clinical deterioration. Wavelet decomposition analysis, however, is unlikely to prospectively distinguish patients at a high risk of arrhythmic events in idiopathic dilated cardiomyopathy in its present form.
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Short-, mid-, and long-term reproducibility of the atrial Signal-Averaged Electrocardiogram in healthy subjects: comparison with the conventional ventricular Signal-Averaged Electrocardiogram.
Pacing and clinical electrophysiology : PACE, 2000Co-Authors: Irina Savelieva, Katerina Hnatkova, A. J. Camm, Kudret Aytemir, Marek MalikAbstract:Although atrial Signal-Averaged Electrocardiogram (SAECG) has been proposed for noninvasive identification of patients with atrial tachyarrhythmias, the substantial variability of the measurement limits the clinical value. The aim of the study was to assess the short- to long-term reproducibility of atrial SAECG and to compare it to that of the conventional ventricular SAECG in 51 healthy volunteers (30 men; age 32 +/- 8 years). In each subject, SAECG recordings were obtained using MAC-VU electrocardiograph and HiRES and PHiRES software (Marquette Medical Systems) and repeated after 5 minutes, 1 day, 1 week, and 1 month. Automatically detected onset and offset of the filtered QRS complex and P wave were subsequently corrected by two independent observers, and the averaged values were used for the analysis. Conventional ventricular SAECG parameters: filtered QRS duration (QRStot), low amplitude signal duration, and root mean square voltage (RMS) of the terminal 40 ms of QRS, and 5 atrial parameters: filtered P wave duration (Ptot), RMS of the terminal 40, 30, 20 ms, and of the entire P wave were obtained. Relative errors of different pairs of measures were used to assess the intrasubject reproducibility. QRStot and Ptot were the most reproducible parameters. The relative errors after 5 minutes, 1 day, 1 week, and 1 month were 0.8% to 2.4% for QRStot, and 1.3% to 4.2% for Ptot. For RMS voltages, the relative errors exceeded 15% in short-term and 20% in long-term recordings. Although Ptot was statistically less reproducible than QRStot, the reproducibility of the former was good and comparable to that of the QRStot. The reproducibility of the voltage parameters was significantly poorer than that of the duration parameters. The study showed a satisfactory short- and long-term reproducibility of Ptot in the atrial SAECG in healthy subjects. However, low reproducibility of the voltage parameters should be considered in clinical applications.
Nabil Elsherif - One of the best experts on this subject based on the ideXlab platform.
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risk stratification for arrhythmic events in patients with nonischemic dilated cardiomyopathy and nonsustained ventricular tachycardia role of programmed ventricular stimulation and the signal averaged Electrocardiogram
Journal of the American College of Cardiology, 1994Co-Authors: Gioia Turitto, Edward B. Caref, Ratan K Ahuja, Nabil ElsherifAbstract:Abstract Objectives . This study investigated prediction of arrhythmic events by the Signal-Averaged Electrocardiogram (ECG) and programmed stimulation in patients with nonischemic dilated cardiomyopathy. Background . Risk stratification in patients with nonischemic dilated cardiomyopathy remains controversial. Methods . Eighty patients with nonischemic dilated cardiomyopathy and spontaneous nonsustained ventricular tachycardia underwent Signal-Averaged electrocardiography (both time-domain and spectral turbulence analysis) and programmed stimulation. All patients were followed up for a mean of 22 ± 26 months. Results . Sustained monomorphic ventricular tachycardia was induced in 10 patients (13%), who all received amiodarone. The remaining 70 patients were followed up without antiarrhythmic therapy. Of the 80 patients, 15% had abnormal findings on the time-domain Signal-Averaged ECG, and 39% had abnormal findings on spectral turbulence analysis. Time-domain Signal-Averaged electrocardiography had a better predictive accuracy for induced ventricular tachycardia than spectral turbulence analysis (88% vs. 66%, p Conclusions . In patients with nonischemic dilated cardiomyopathy, 1) there is a strong correlation between abnormal findings on the time-domain Signal-Averaged ECG and induced ventricular tachycardia, but both findings are uncommon; and 2) normal findings on the Signal-Averaged ECG, as well as failure to induce ventricular tachycardia, do not imply a benign outcome.