title: Clinical results with single lead VDD pacing.
abstract: 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 for an atrial lead. The purpose of this study was to investigate the clinical performance of a novel VDD pacemaker and the reliability of atrial sensing via the "floating' atrial electrode.
  
  
  METHODS
  31 patients (10 females; age 64 +/- 13 years) underwent an implantation of a VDD pacemaker system (Intermedics UNITY). The patients were analyzed with regard to implantation parameters, complications and postoperative atrial sensing performance using the diagnostic data of the pacemaker memory. The mean follow-up was 6.3 (1-18) months.
  
  
  RESULTS
  The implantation procedure did not differ from that of conventional single chamber pacemakers. Dislocation of a ventricular electrode was the only complication observed. The P wave at implantation was 1.6 +/- 0.9 mV and dropped to 0.9 +/- 0.4 mV at predischarge. During follow-up the atrial sensing threshold remained stable. The atrial sensing performance (percentage of atrial synchronous ventricular complexes) after reprogramming the highest atrial sensitivity was 99.7%. Two patients (6%) developed atrial fibrillation. 29 patients (94%) remained in VDD mode as primarily intended.
  
  
  CONCLUSIONS
  From these results it is concluded that VDD pacing represents an excellent alternative in patients with atrioventricular block and intact sinus node function. The atrial sensing was found to be reliable.
authors.affiliation: Department of Cardiothoracic Surgery, Universität Regensburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Liebold
authors.forename: J
authors.initials: J
authors.lastname: Merk
authors.forename: C
authors.initials: C
authors.lastname: Keyl
authors.forename: H
authors.initials: H
authors.lastname: Aebert
authors.forename: D E
authors.initials: DE
authors.lastname: Birnbaum
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004562:Electrocardiography / Q000295:instrumentation; D005260:Female; D005500:Follow-Up Studies; D006327:Heart Block / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D011474:Prosthesis Design; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D012984:Software