VDD MODE SINGLE ELECTRODE PACEMAKER - IND ICATIONS, RESULTS AND LIMITATIONS

Several authors have reported the single atrioventricular (AV) electro de, comprising an atrial dipole floating in the right atrium, to be a system capable of providing results which are just as satisfactory as those of conventional systems (DDD). Between August 1992 and March 199 5, a VDD single electrode pacemaker was implanted in 65 patients (mean age: 73 years +/- 17.2). The indication for implantation was isolated high degree AVE with no apparent sinus dysfunction. Four pacemakers w ere used: Vitatron (n = 24), Intermedics (n = 23), Medico (n = 13), Bi otronik (n = 5). Intraoperative atrial endocavitary recording was 1.8 mV +/- 0.74. 17 patients died from a cause unrelated to pacemaker dysf unction. 4 patients were lost to follow-up. The remaining 44 patients were reviewed in our centre with a mean follow-up of 14.5 months +/- 7 months. Seven pacemakers (16 %) were reprogrammed in VVI or VVI (R) m ode, because of permanent atrial fibrillation in 3 cases, complete los s of atrial reception in 2 cases and late onset sinus dysfunction in 1 case. In the 41 patients in sinus atrial rhythm, the atrioventlicular synchronization rate was greater than 90 % in 88 % of patients, equal to 76.3 % in 2.4 % of patients and atrioventricular synchronization w as impossible in 9.6 % of cases. Conclusion:the overall results of our preliminary experience of VDD mode single electrode pacemaker are mod erate. The poor results essentially concerned patients with paroxysmal atrial arrhythmias prior to pacing.