Body surface potential mapping (BSPM) is a method providing a noninvasive assessment of the changes ongoing in the electric field of the heart. In the present study, the weakly recognized kind of the surface maps--isochrone maps that reflect in the best manner a pathway of the depolarization front propagation within the heart conduction system. BSPM was obtained using a HPM-7100 Fukuda Denshi system, which enables collecting a synchronic electrocardiographic recordings from 87 electrodes in the cylindrical system. The study population constituted 30 healthy subjects (15 females and 15 males) with the mean age of 23.9 +/- 4.56 years. The considered electrocardiogram from the all subjects appeared to be within the normative range. In order to obtain a pattern reflecting a depolarization trajectory in the human heart, the ventricular activation time maps (VAT), on the plane and superficial, were constructed with the own software. On the basis of the VAT maps obtained from the examined group, the group-mean VAT map for the normal subjects was created. Isochrone maps render much more information about heart activation spread than the standard 12-leads electrocardiography system. Using isochrone maps, one can monitor precisely a depolarization trajectory in the individual heart portions. The values and distribution of isochrones determine a velocity of activation propagation within the heart conduction system. Analysis of the isochrone maps collected in the normal subjects confirmed the activation pathway of the ventricles, starting from atrioventricular junction, via His bundle and its branches and finally to the myocardium through Purkinje fibres. In the examined group, no significant differences in relation to the isochrones distribution were found, therefore the group-mean VAT map was assumed as a reference pattern. The pattern of distribution and values of VAT map established for the normal subjects can be used in the further investigations concerning a diagnosis of the heart conduction system disturbances.