[Atrioventricular "sequential" stimulation by implantable "bifocal" stimulator].

The "bifocal pacemaker achieves a sequential" stimulation which reproduces the physiological atrio-ventricular sequence. This type of stimulation has the advantages of atrial stimulation without the disadvantages of being inefficient when an atrio-ventricular block exists or supervenes. The pacemaker was used by the endocavity route in 12 patients. The indications included a disease of the sinus node (8 cases), supra-ventricular arrhythmias associated to conduction disorders (3 cases) and a cardiomyopathy with conduction disorders (1 case). The preliminary results were appraised after two to twenty four months. One displacement of the ventricular electrode was noted. On the other hand no displacement of the atrial electrode was reported. One battery was worn out after 19 months. The "bifocal" pacemaker was efficient in the treatment of symptoms which justified its implantation. Or particular interest were the results obtained in patients with no supraventricular arrhythmias. This pacemaker may be of use: 1) in the disease of the sinus node, in particular in the tachycardia-bradycardia syndrome; 2) in supraventricular arrhythmias associated to paroxystic conduction disorders; 3)in patients with an alteration of the myocardial function and for whom the atrial contribution to cardiac output is essential.