title: Ambulatory Holter monitoring in asymptomatic patients with DDD pacemakers - do we need ACC/AHA Guidelines revision?
abstract: BACKGROUND
  We sought to determine the usefulness of ambulatory 24-hour Holter monitoring in detecting asymptomatic pacemaker (PM) malfunction episodes in patients with dual-chamber pacemakers whose pacing and sensing parameters were proper, as seen in routine post-implantation follow-ups.
  
  
  METHODS
  Ambulatory 24-hour Holter recordings (HM) were performed in 100 patients with DDD pacemakers 1 day after the implantation. Only asymptomatic patients with proper pacing and sensing parameters (assessed on PM telemetry on the first day post-implantation) were enrolled in the study. The following parameters were assessed: failure to pace, failure to sense (both oversensing and undersensing episodes) as well as the percentage of all PM disturbances.
  
  
  RESULTS
  Despite proper sensing and pacing parameters, HM revealed PM disturbances in 23 patients out of 100 (23%). Atrial undersensing episodes were found in 12 patients (p < 0.005) with totally 963 episodes and failure to capture in 1 patient (1%). T wave oversensing was the most common ventricular channel disorder (1316 episodes in 9 patients, p < 0.0005). Malfunction episodes occurred sporadically, leading to pauses of up to 1.6 s or temporary bradycardia, which were, nevertheless, not accompanied by clinical symptoms. No ventricular pacing disturbances were found.
  
  
  CONCLUSIONS
  Asymptomatic pacemaker dysfunction may be observed in nearly 25% of patients with proper DDD parameters after implantation. Thus, ambulatory HM during the early post-implantation period may be a useful tool to detect the need to reprogram PM parameters.
authors.affiliation: Department of Electrocardiology, Medical University of Lodz, Poland.
authors.forename: Michal
authors.initials: M
authors.lastname: Chudzik
authors.forename: Artur
authors.initials: A
authors.lastname: Klimczak
authors.forename: Jerzy Krzysztof
authors.initials: JK
authors.lastname: Wranicz
keywords: DDD pacemaker; ambulatory Holter monitoring; pacemaker dysfunction