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Joint research project

Study of efficacy of ECG risk markers in different populations

Project leaders
Giovanni Bortolan, Ivaylo Ivanov Hristov
Agreement
BULGARIA - BAS - Bulgarian Academy of Sciences
Call
CNR-BAS 2016-2018
Department
Biomedical sciences
Thematic area
Biomedical sciences
Status of the project
New

Research proposal

** Present state of knowledge in the field, significance and objectives of the joint research.
The proposed project arises from the common interest of Italian and Bulgarian researchers in developing innovative biomedical ECG signal processing algorithm/techniques for studying specific ECG risk markers of arrhythmias, incidental heart failure and sudden cardiac death (SCD).
The considerable experience of the two proponent research groups , (Institute of Neuroscience CNR and previously Institute of Biomedical Engineering of CNR and Institute of Biophysics and Biomedical Engineering of BAS), in computerized Electrocardiography and in Biomedical signal processing, will permit to study and test quantitative non-invasive methodologies for the measurement of different ECG risk markers. The recent ECG markers studied by the two groups are: T-wave alternans (TWA), QRS alternans, the variations of the amplitude of QRS and T-wave , QRS-T angle and ST-segment changes.
For example, T-wave alternans (TWA) and QRS alternans (QRSA) are electrophysiological phenomenon and appears in ECG as a consistent fluctuation in repolarization morphology on every-other beat basis. In most cases TWA or QRSA are in the microvolt range, invisible to the naked eye, and can be detected by specific biomedical ECG signal processing algorithms. TWA is a proven risk marker for occurrence of malignant arrhythmias, Torsade de Pointes, and cardiac death. It was found that TWA is more common among diabetics and patients who undergo coronary artery bypass grafting (CABG), and is predictor of postoperative atrial fibrillation. There are controversial results considering the clinical significance of QRSA, and the research is still active.
The variations of the amplitude of QRS and T-wave are two markers studied with particular interest in Hemodialysis groups. For example variations of QRS amplitude can be an indicator of the risk of extracellular water and blood volume increase, or the T-wave amplitude change can have a negative dependence/correlation to Sodium (Na) and positive to potassium (K) blood concentration, and this parameter can be an indicator for electrolyte concentration and hyperkalemia.
A wide QRS-T angle has emerged as an abnormal electrocardiographic repolarization marker in stratifying cardiac risk in various study populations. Wide spatial and frontal QRS-T angle values have been shown to be predictive of cardiovascular events including incident heart failure, ventricular arrhythmias, and SCD.
ST-segment changes are common during the early postoperative period after CABG in patients without enzymatic or echocardiographic evidence of preoperative myocardial infarction (MI).
The main objective of this proposal is consisting of the automatic evaluation of cardiac risk markers (like TWA, QRSA, QRS, T-wave and ST-segment amplitudes, and QRS-T angle) and the study of the efficacy of these parameters in different diagnostic groups. In addition, controllable risk factors (smoke, high blood pressure, high blood cholesterol, and obesity), not controllable risk factors (gender, age and heredity) and other clinical data will be considered in this study. Three different groups of patients will be followed up: 1) patients that performed stress ECG test, 2) a set of dialyzed patients, 3) and a group of patients undergone coronary artery bypass grafting (CABG) surgery.
The project will be the occasion to strengthen existing synergies between the two groups and will provide new competitive edges to the scientific activities in both CNR and BAS.
** Background of cooperation and envisaged results and benefit:
The mutual interest of the two research groups arises from a significant international scientific cooperation, and positive results are expected because of previous successful cooperation of the team members : 3 bilateral research projects CNR-BAS, 2 NATO-Science scholarships, 1 trilateral project between IN-CNR (previously ISIB-CNR), IBPhBME, and St. George's University of London, and a scholarship by "Short Term Mobility Program", CNR, 2014.
The results of the previous (long-lasting) cooperation between IN-CNR (previously ISIB-CNR) and IBPhBME-BAS are documented by the numerous publications , in particular by 35 journal publications and one book chapter.
In addition, the Italian group will take advantage from this cooperation because it represents a very strategic integration for increasing the value of their expertise and competence in biomedical signal processing.

Research goals

The main objective of this project is the automatic evaluation of cardiac risk markers (like TWA, QRSA, QRS, T-wave and ST-segment amplitudes, and QRS-T angle) and the study of the efficacy of these parameters in different diagnostic groups. In addition, controllable risk factors (smoke, high blood pressure, high blood cholesterol, and obesity), not controllable risk factors (gender, age and heredity) and other clinical data will be considered. These objectives can be performed through the following steps:
1. Study and evaluation of innovative Pattern recognition and Biomedical signal processing algorithms for measurement of ECG risk markers.
2. Alternative methods of TWA and QRSA in addition to our successfully tested and awarded method will be tested and validated, testing their clinical significance.
3. Stratification to the risk of a sudden cardiac death and other critical arrhythmias will be considered with different ECG markers.
4. The temporal modifications of the status of the patients will be considered for evaluating the efficacy of ECG risk markers.
5. Three different groups of patients will be followed up (with annual schedule):
- patients that performed stress ECG test (Cardiology Dept. , National Cardiology Hospital, Sofia)
- a set of dialyzed patients (Hemodialysis Dept., National Cardiology Hospital, Sofia,)
- a group of patients undergone coronary artery bypass grafting (CABG) surgery (Cardiac Surgery Dept. , City Clinic, Sofia).

Last update: 07/06/2025