[The vectorcardiogram of patients with artificial pacemakers]

Frank's technique has been used to study the behaviour of the vectorial loop in 20 subjects wearing fixed frequency pacemakers. A broad study has been carried out non characteristics and modalities of transmission of the artificial stimulus. The morphological features of the vectorcardiogram differ in accordance with the location of the stimulated point. Special attention is paid to the possibility of the catheter-electrode penetrating the coronary sinus during right intracavitary pacing and the consequent vectorial and radiological characteristics such an eventuality involves. Some remarks are offered on the orientation of the extrastimulus, depending on its point of origin. It is concluded that knowledge of the course of the vectorial curve may be extremely useful for establishing the site of the extrastimulus in pacemaker wearers.