title: [Usefulness of width and amplitude of P wave for prognosis of the efficacy of atrial sensing in patients with an implanted VDD pacemaker].
abstract: VDD stimulation is accepted as alternative mode of cardiac pacing to DDD in patients with atrio-ventricular (AV) conduction block and preserved sinus node function (SA).
  
  
  OBJECTIVE
  An attempt has been made to determine the relationship between width and amplitude of the P wave obtained during assessment the patient for the implantation procedure and the effectiveness of AV synchronization (PAS).
  
  
  METHODS
  The study involved a group of 65 patients (43 male, 22 female), aged 66.6 +/- 12.7 with clinically significant disturbances of AV conduction, who did not reveal symptoms of concomitant disturbance in SA node automaticity. The width and amplitude of the P wave of the surface ECG were studied prior to the implantation procedure. Follow-up was carried out 3-4 days and 1, 3, 6 and 12 months after the procedure. The effectiveness of PAS was estimated by event counter read-out.
  
  
  RESULTS
  Over the 12-month follow-up, the average value of the PAS coefficient was 95% for the entire group of patients. In 74% (subgroup A) synchronization was highly effective (PAS > or = 95%); in the remaining 26% (subgroup B) PAS occasionally fell below 95%. A statistically significant correlation between the width of the P wave of the surface ECG and the effectiveness of PAS was clearly demonstrated. In subgroup B, P wave was longer than in subgroup A (105 +/- 16 vs. 94 +/- 14 ms; p < 0.005). The width of P wave above 100 ms was the cutoff value of the ROC curve predicting PAS < 95%.
  
  
  CONCLUSIONS
  The width of P wave obtained from surface ECG is correlated with effective AV synchronization. The value above 100 ms was predisposed to atrial undersensing.
authors.affiliation: Jagiellonian University, Collegium Medicum, John Paul II Hospital in Krakow, Poland, Institute of Cardiology, Department of Electrocardiology. jlelakow@szpitaljp2.krakow.pl
authors.forename: Jacek
authors.initials: J
authors.lastname: Lelakowski
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Czunko
authors.forename: Jacek
authors.initials: J
authors.lastname: Szczepkowski
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000517:prevention & control; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004562:Electrocardiography; D004868:Equipment Failure; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D011379:Prognosis; D013612:Tachycardia, Ectopic Atrial / Q000175:diagnosis*; D055815:Young Adult