Determination of an accurate electrocardiographic (ECG) baseline is generally needed for localization of ventricular arrhythmias with body surface potential mapping (BSPM). We suggest a novel signal processing method for ECG baseline reconstruction during monomorphic ventricular tachycardias (VT). The method is based on an assumption that VT consists of similar ventricular extrasystolic beats with overlapping depolarization and repolarization. The sequential reconstruction algorithm utilizes information of small variations in the heart rate and yields a non-overlapping QRST-signal, provided that the measurement set-up has a high enough temporal resolution to avoid distortions due to sampling differences and misalignment of individual beats. The reconstructed QRST-signal is utilized to subtract overlapping T-waves from the QRS complexes during VT. The use of the method is demonstrated with clinically measured BSPM data.

The authors present a new method based on Kohonen networks for the analysis and classification of body surface potential map (BSPM) sequences. First, BSPM sequences obtained from a time interval of the cardiac cycle (e.g. QRS, ST) are presented to an untrained Self-Organizing Map (SOM). During the learning process the SOM units organize in such a way that similar BSPMs are represented in particular areas of the SOM. Time traces from the cardiac activation are then created on the trained SOM and forwarded to a Learning Vector Quantization network for final classification. In this paper the method was applied to BSPM sequences obtained during catheter pace mappings with the aim to noninvasively localize sources of ventricular tachycardia.

The authors describe the use of a new body surface potential mapping (BSPM) system for arrhythmia treatment in Helsinki University Central Hospital. First, the implementation of the mapping system is presented. Then, the method's clinical use is described and finally, the benefits for radiofrequency ablation therapy are considered.

The authors describe a novel method for electrocardiographic (ECG) baseline reconstruction of rapid Ventricular Tachycardia (VT) by removal of the overlapping T-wave from electrocardiographic signal. Reconstruction is done sequentially by extracting information lying in RR-variation zone. This sequential algorithm yields a non-overlapping pure QRST-signal, which can be used to subtract overlapping T-waves from ventricular tachycardia. Finally the authors demonstrate the use of the method in Body Surface Potential Mappings (BSPM)

We have developed semi-automatic methods for reconstructing boundary element thorax models from magnetic resonance (MR) data of the heart. The thorax, the lungs and the heart were segmented from the MR images, and then triangulated. A registration method was applied to convert the magnetic resonance coordinates to the frame of the MCG recordings, and to represent the non-invasive MCG localization results on the MR images