The isopotential body surface atrial maps in healthy children of different age groups.

Isopotential body surface maps during atrial excitation were examined by ten beats addition method of the P waves in 32 healthy children divided into three age groups. The moving pattern of the maxima and the minima, and the distribution of areas of positive and negative potentials in each group were similar to those of adults. Quantitative analysis of the duration and amplitude of the anterior and the left maximum, and the shift time from the former to the latter were done. In children the duration and amplitude of the anterior maximum were always larger than those of the left maximum in contrast to findings in adults where no significant difference was found in their values. The higher amplitude of the anterior maximum was found mainly in the youngest group. These parameters of the P maps were also examined in 12 cases of atrial septal defect (ASD). The amplitude and duration of the anterior maximum were larger than those of healthy children at each age group, although the P wave by the conventional ECG did not reveal signs of right atrial overload. These results suggest that the body surface maps of the P waves are useful diagnostic methods to detect atrial disorders in children.