title: Utility of the surface ECG before VDD pacemaker implantation.
abstract: BACKGROUND
  VDD pacemakers may be implanted in the setting of atrioventricular block with preserved sinus function. Their main advantage over DDD pacemakers is use of a single lead. However, low-amplitude atrial electrograms (EGMs) recorded from the free-floating atrial electrode may lead to undersensing. There is currently no way of predicting EGM amplitude prior to implantation and to thus identify candidates who may be safely implanted with a VDD pacemaker.
  
  
  OBJECTIVE
  We sought to investigate whether the P-wave amplitude measured on the standard surface ECG correlates with the atrial EGM amplitude measured by the single-pass lead at implantation.
  
  
  METHODS
  Data on 122 patients implanted with a VDD pacemaker at our institution were reviewed. Atrial EGM amplitudes measured at implantation by the single-pass lead were correlated with the maximal P-wave amplitude on the surface ECG recorded just prior to implantation.
  
  
  RESULTS
  There was a highly significant correlation between the maximal P-wave amplitude on the surface ECG and the atrial EGM (Pearson's correlation 0.313, P<0.001). Multivariate analysis showed that maximal P-wave amplitude was independently associated with atrial EGM amplitude (p=0.003). For the overall population, an EGM amplitude of <0.9 mV was present in only 11/122 (9%) cases. An atrial EGM amplitude of <0.9 mV was found in 10/69 (14%) of patients with a maximal surface P-wave < or =0.1 mV but only in 1/53 (2%) of those with >0.1 mV (p=0.023).
  
  
  CONCLUSIONS
  Low-amplitude atrial EGMs at implantation are found in a minority of patients with single-pass leads. However, patients with a maximal surface P-wave amplitude of >0.1 mV are especially unlikely to have a low atrial EGM amplitude and may be good candidates for a VDD pacemaker.
authors.affiliation: Cardiology Service, University Hospital, 23, Micheli-du-Crest, 1211 Geneva, Switzerland. haran.burri@hcuge.ch
authors.forename: Haran
authors.initials: H
authors.lastname: Burri
authors.forename: Stéphane
authors.initials: S
authors.lastname: Noble
authors.forename: Henri
authors.initials: H
authors.lastname: Sunthorn
authors.forename: Pierre-André
authors.initials: PA
authors.lastname: Dorsaz
authors.forename: Isabelle
authors.initials: I
authors.lastname: Vieira
authors.forename: Dipen
authors.initials: D
authors.lastname: Shah
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017046:Cost Savings; D004562:Electrocardiography; D004567:Electrodes, Implanted; D005260:Female; D006327:Heart Block / Q000175:diagnosis / Q000191:economics / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial / Q000191:economics; D012189:Retrospective Studies