Onthogenic changes in the orientation of the ventricular activation and recovery mean vector in pig

The effect of physical maturation on the ventricular activation and recuperation mean vectors has been analyzed in pigs during a period of time between 1 day and 6 months of age. The results showed that whilst the vectorial magnitude of AQRS on the horizontal plane was not affected by physical maturation, that of the spatial vector (SAQRS) underwent an increase during the period of study. Likewise, it was determined that the ventricular activation front showed an inclination to change its orientation from caudal, sinistral or dextral, to dextrocranial, maintaining the dorsal orientation in all individuals. For the ventricular recuperation mean vector the results showed that its vectorial magnitudes both on the horizontal plane and in space underwent an increase during the 6 months analyzed. As regards the direction of the recuperation front, it was established that, at any age, the preferential orientation is caudal, with a deviation to the left in a high percentage of the 20 day to 3 month old pigs, and ventral in all individuals.