Figure 2

Portable ECG with markers. The portable ECG device adopted for this study with attached on the correspondent three markers. The side of each marker measures 4 cm (a). The rigid T-shaped frame enclosing the three markers placed on the thorax of a mannequin. The upper side of the lowest marker is placed in correspond to the xiphoid process (b). Schematic representation of the reference frame adopted in the trials and the relative positions of the precordial electrodes V1, V2, V3, V4, V5 and V6 (c).