[Long-term hemodynamic results of bifocal pacemaker stimulation]

Before and during the half year after implantation of a bifocal cardiac pacemaker haemodynamic investigations were done in 16 patients using various stimulations. Compared with ventricular stimulation bifocal pacemaker treatment resulted in an increase of cardiac ejection by 31%, the optimal AV-time being between 150 and 200 ms. Maximum benefit was obtained in patients with primary decreased cardiac index (less than 2.50 l/min X m2). In these patients the increase of cardiac index during atrial stimulation compared to ventricular stimulation was 43%. In pre-existing sinus bradycardia left-ventricular ejection fraction was significantly increased despite lowering of enddiastolic filling pressure both at rest and during bicycle ergometry. These positive haemodynamic changes were demonstrable unaltered 6 months after pacemaker implantation.