[Electrode surface areas, pulse duration and stimulation threshold. Acute and chronic study with endocardial unipolar electrodes (author's transl)].

Acute and chronic voltage-threshold of cardiac stimulation was studied in patients with complete A-V block. Endocardial unipolar electrode with three different cathodial surface areas were used (54, 22 and 12 sqmm), and tested with rectangular stimulus of variable duration (from 0.2 to 3.5 msec.). The results show that the threshold values, at first implantation and at pulse-generator replacements, are low when short-duration stimulus and smaller electrode surface area are used. The practical advantages of this study are evident.