CARDIAC MICROPOTENTIALS REACHED FROM ONE SYSTOLE AS NONDIPOLAR RESIDUE BY SINGULAR-VALUE DECOMPOSITION

Cardiac micropotentials are considered to have a predictive value in c ritical ventricular tachycardia or sudden death. These micropotentials are obtained by numeric filtration of the result of sequential averag ing of about 200 systoles (i.e. of measurement at about 3 min interval ) which is significantly influenced by known intraindividual ECG varia bility. It follows from our previous studies that the non-dipolar resi due (i.e. the sum of all components of an equivalent source of the hea rt electrical field with the exception of the first three dominant dip olar components) corresponds by its nature to the cardiac micropotenti als, i.e. to late potentials. Verification of this hypothesis utilizin g singular value decomposition and replacing the sequential averaging by 'surface' averaging of the matrix of synchronously measured ECGs is the aim of this project. The results of the present study can be cons idered as a confirmation of this hypothesis. These results provide a b etter understanding of the structure of the body surface potential dis tribution and for clinical purposes they make it possible to attain ca rdiac micropotentials (late potentials) from one systole.