CLINICAL-RESULTS WITH SINGLE-LEAD VDD PACING

Objective: For patients with atrioventricular block single lead atrial synchronous ventricular pacing (VDD) may have advantages compared to conventional dual chamber pacing (DDD) since it eliminates the need fo r an atrial lead. The purpose of this study was to investigate the cli nical performance of a novel VDD pacemaker and the reliability of atri al sensing via the 'floating' atrial electrode. Methods: 31 patients ( 10 females; age 64 +/- 13 years) underwent an implantation of a VDD pa cemaker system (Intermedics UNITY). The patients were analyzed with re gard to implantation parameters, complications and postoperative atria l sensing performance using the diagnostic data of the pacemaker memor y. The mean follow-up was 6.3 (1-18) months. Results: The implantation procedure did not differ from that of conventional single chamber pac emakers. Dislocation of a ventricular electrode was the only complicat ion observed. The P wave at implantation was 1.6 +/- 0,9 mV and droppe d to 0.9 +/- 0.4 mV at predischarge. During follow-up the atrial sensi ng threshold remained stable. The atrial sensing performance (percenta ge of atrial synchronous ventricular complexes) after reprogramming th e highest atrial sensitivity was 99.7% Two patients (6%) developed atr ial fibrillation. 29 patients (94%) remained in VDD mode as primarily intended. Conclusions: From these results it is concluded that VDD pac ing represents an excellent alternative in patients with atrioventricu lar block and intact sinus node function. The atrial sensing was found to be reliable. (C) 1997 Elsevier Science B.V.