Pacemakers: Dual or Single Chamber Implantation

Abstract

One hundred and seventy-five consecutive patients receiving transvenous per manent pacemakers were reviewed in a comparison of the morbidity of 70 atri oventricular (AV) implantations (DDD 60, DVI 10) and 105 ventricular implantations (VVI 104, VVIR 1). Two atrial lead dislodgements occurred in the first 10 AV implants. Screw-in atrial electrodes eliminated dislodgement in 60 subsequent cases. Ventricular electrode dislodgement was present in 13.3% of the first 15 implants, but in only 1.2% of the next 90 implants, when smaller tined leads became available. Routine use of active endocardial fixation improved the overall 2.8% electrode malposition and dislocation rate to 1.4% in the AV group and 0.9% in the ventricular group. Skin erosion and infection was found in 1.4% of AV implants as compared with 3.8% of ventricular implants and appeared related to pulse generator size. Moreover, 5.7% of VVI implants re quired upgrading to DDD units for treatment of pacemaker syndrome. Improved pacemaker and lead technology lowered the overall 4% early secondary inter vention rate to 2.9% for AV and 1.9% for ventricular implants over the latter 150 cases. The data suggests that dual-chamber implantation can be accomplished with morbidity comparable to that of single-chamber implantation. The inher ent hemodynamic and electrophysiologic advantages make the DDD unit an at tractive choice in the majority of patients with appropriate atrial rhythm who require permanent pacing.