Method for the investigation of the electromechanical activity of the heart using time-frequency tools

The waveform analysis of the electrocardiogram (ECG) and phonocardiogram (PCG) for heart monitoring has proven the capability to provide important information, which can prevent the number of heart attacks and resulting deaths. While of a different nature, the fusion of these two dependent signals could improve the overall recognition performance of the mechanical and electrical activity of the heart. Acoustic cardiography, synchronizing and analyzing electrical activity and heart sound, permits a more detailed analysis of the timing characteristics of the heart. The portability and low cost of acoustic cardiography makes it useful for the estimation and monitoring of patients with known or suspected heart disease for both clinical and investigational applications. In this field, time-frequency representation (TFR) methods are used to study the ECG and PCG signals since they are non-stationary bio-signals. Due to its richness both in time and in frequency domain, and its robustness against noise, it has recently become a favorite tool. These tools could provide macroscopic time informations (S1, S2, Q, R ⋯) and microscopic details (e.g. heart sounds' split, murmurs) that will be beneficial for diagnosis purposes. In this study, a number of coordinated research projects in the heart activity analysis (MARS500, E-Care and data from Aalborg University) are presented, and TFR tools are demonstrated to have a large potential in the acoustic cardiography for monitoring heart function. Design of a computerbased monitor using the techniques specified in this study is discussed along with relative strengths and weaknesses of such a system.