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Amit G.,Biological Signal Processing Ltd | Granot Y.,Biological Signal Processing Ltd | Abboud S.,Tel Aviv University
Journal of Electrocardiology | Year: 2014

Over four decades of high frequency electrocardiography research have provided a body of knowledge about QRS changes during myocardial ischemia, and the techniques to measure and quantify them. High-frequency QRS (HFQRS) components, being closely related to the pattern of ventricular depolarization, carry valuable clinical information. Changes in HFQRS amplitude and morphology have been shown to be sensitive diagnostic markers of myocardial ischemia, often superior to measures of ST-T segment changes. Clinical studies in patients undergoing exercise testing have consistently demonstrated the incremental diagnostic value of HFQRS analysis in detection of demand ischemia. In 6 studies that evaluated the HyperQ™ technology, the average sensitivity and specificity of HFQRS analysis were 75% ± 6% and 80% ± 6%, respectively, compared to average sensitivity 48% ± 16% and average specificity 70% ± 15% of ST segment analysis. In patients with acute supply ischemia, recent studies characterized and quantified the ischemic HFQRS patterns. HFQRS morphology index was found to be higher in patients with acute coronary syndrome (ACS), compared to non-ischemic, with good sensitivity in patients without ST elevation. These research findings may be translated into commercially-available ECG systems and be used in clinical practice for improved diagnosis and monitoring of myocardial ischemia. © 2014 Elsevier Inc. Source


Amit G.,Biological Signal Processing Ltd | Toren Y.,Biological Signal Processing Ltd | Davrath L.R.,Biological Signal Processing Ltd | Toledo E.,Biological Signal Processing Ltd | Abboud S.,Tel Aviv University
International Journal of Medical Engineering and Informatics | Year: 2013

Exercise ECG testing (EET) has limited accuracy in diagnosing coronary heart disease (CHD). High-frequency QRS (HFQRS) analysis is a new technology that improves the diagnostic performance of EET. We analysed the potential economic and healthcare benefits of HFQRS technology. The changes in utilisation of cardiac imaging tests and expenditures on medical treatment were studied using probabilistic models. A decision tree model was used to assess the expected costs of CHD workup and a prognostic Markov model was used to estimate long-term consequences. The models indicated that compared with EET, HFQRS-based workup results in a reduction in superfluous imaging tests. Analysis of long-term changes indicated a reduction in adverse events among CHD patients, with a decrease in overall medical costs and an increase in quality-adjusted life years. HFQRS technology is a promising tool for diagnosing CHD that may reduce medical costs while providing favourable prognostic outcomes. Copyright © 2013 Inderscience Enterprises Ltd. Source


Amit G.,Biological Signal Processing Ltd | Galante O.,Ben - Gurion University of the Negev | Davrath L.R.,Biological Signal Processing Ltd | Luria O.,Biological Signal Processing Ltd | And 2 more authors.
Annals of Noninvasive Electrocardiology | Year: 2013

Background The 12-lead electrocardiogram (ECG) is a primary tool in the evaluation and risk stratification of patients with suspected acute myocardial infarction (AMI), even though the initial ECG of these patients is often normal or nondiagnostic. Myocardial ischemia induces depolarization changes that can be quantified by analysis of high-frequency QRS (HFQRS) components. We aimed to demonstrate the potential usefulness of HFQRS analysis in diagnosing myocardial ischemia by characterizing the morphological patterns of the HFQRS signals in patients with AMI before and following reperfusion. Methods Five-minute high-resolution ECG was acquired from 30 patients with AMI (age 55 ± 11 years, 26 men) upon their admission to the intensive coronary care unit (ICCU). Serial ECGs were acquired following coronary revascularization and after additional 24 hours (24h). High-frequency morphology index (HFMI), quantifying the extent of ischemic patterns was computed by a custom software, and its values were compared between the serial ECG measurements. Results HFMI values were significantly higher on the admission ECG as compared to the post intervention ECG (4.6 ± 2.9% vs 3.4 ± 2.3%, P < 0.05) and to the 24h ECG (4.6 ± 2.9% vs 2.8 ± 2.1%, P < 0.01). In 79% of the patients who were successfully revascularized HFMI value decreased from admission ECG to 24h ECG. Conclusions Analysis of HFQRS morphology in patients with AMI provides information about the existence and severity of myocardial ischemia. HFQRS analysis may aid in risk stratification of patients with suspected myocardial ischemia, complementarily to conventional ECG. ©2012, Wiley Periodicals, Inc. Source


Rosenmann D.,Shaare Zedek Medical Center | Mogilevski Y.,Shaare Zedek Medical Center | Amit G.,Biological Signal Processing Ltd | Davrath L.R.,Biological Signal Processing Ltd | Tzivoni D.,Shaare Zedek Medical Center
Journal of Electrocardiology | Year: 2013

Background: Exercise ECG testing in women for the diagnosis of coronary artery disease (CAD) has a higher false-positive rate compared to men. Consequently, women referred for coronary angiography following a positive exercise test often have normal coronary arteries or non-obstructive lesions. Analysis of the high-frequency components of the QRS complexes (HFQRS) has been reported to provide a sensitive means of detecting myocardial ischemia, independent of gender. The aim of the present study was to prospectively test the diagnostic performance of HFQRS and conventional exercise ECG in detecting stress-induced ischemia in women referred for coronary angiography. Methods: The study included 113 female patients (age 64 ± 9 years) referred for non-urgent angiography. Patients performed a symptom-limited treadmill exercise test prior to angiography. High-resolution ECG was acquired during the test and used for both HFQRS and conventional ST-segment analyses. HFQRS diagnosis was determined by computerized analysis, measuring the stress-induced reduction in HFQRS intensity. The diagnostic performance of HFQRS, ST-segment analysis and clinical interpretation of the exercise test were compared, using angiography as a gold standard. Results: HFQRS provided sensitivity of 70% and specificity of 80% for detection of angiographically significant coronary obstruction (≥ 70% stenosis in a single vessel or ≥ 50% in the left main artery). HFQRS was more specific than exercise ECG test (80% vs. 55%, P <.005), as well as more accurate (76% vs. 62%, P <.01). The number of ECG leads with ischemic HFQRS response correlated with the severity of CAD. HFQRS was highly specific (93%) in patients who achieved their age-predicted target heart rate, and retained its diagnostic accuracy in subgroups of patients with resting ECG abnormalities or inconclusive exercise ECG. Conclusions: HFQRS analysis, as an adjunct technology to exercise stress testing, may improve the diagnostic value of the ECG, and reduce the number of unnecessary imaging and invasive procedures. © 2013 Published by Elsevier Inc. Source

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