[From the history of electrocardiography].

The basis of electrocardiography was established in the innovative years between 1850 and 1930. Men like Waller, DuBois-Reymond, and Einthoven were the innovators of what we today recognize as modern electrocardiography. Others, like Lewis and Bedford, introduced analysis of cardiac arrhythmias, of the S-T segment and the QRS complex. The article gives an overview of this innovative period and its instrumentation.