1. Apparatus for graphical representation of a train of ECG complexes, each of said electrocardiogram (ECG) complexes respectively comprising an R wave and a T-P interval and having respectively variable isoelectric baselines, the apparatus comprising: electrodes; an isoelectric alignment unit configured to obtain electrocardiogram (ECG) signals from said electrodes when said electrodes are placed on a subject and to carry out an alignment for each complex comprising aligning said complexes in terms of signal amplitude by obtaining a respective T-P interval for each ECG complex, using said T-P interval to infer said respective isolectric baseline and aligning said isoelectric baselines; and a temporal alignment unit configured to align said complexes temporally using a predetermined point on respective R-waves, thereby to graphically represent said train of ECG complexes as a superposition of said ECG complexes into a single complex.