The catheter is guided along a blood vessel of a patient by the bipolar electrode functioning as a mobile sensor on the catheter tip connected to the electronic unit to monitor the advance of the catheter and determine any modification of successive signals received from the bipolar electrode in order to detect any deviation of the catheter tip from the required path along the blood vessel and to deliver control signals comprising a GO signal, a STOP signal or an END signal to respectively enable, interrupt or terminate the advance of the catheter. The bipolar electrode moreover serves to verify the contact of the catheter tip with the wall of the heart cavity of the patient by creating impulses and detecting the appearance of corresponding induced signals on a surface cardiogram of the patient. The combination of the bipolar electrode on the catheter with the electronic unit provides a portable catheterization system particularly suitable for performing urgent cardiac catheterizations outside hospitals.