iPod and Other MP3 Players on ICDs and Pacemakers in Children
Condition: Heart Block; Bradycardia; Tachycardia; Arrhythmia
MeSH terms: Arrhythmias, Cardiac; Tachycardia; Bradycardia; Heart Block
Study type: Observational

Summary: 
      Unlike phones, which are commonly held to the ear, music is now available via portable MP3
      players and they can be held almost anywhere. Thaker et al state that Apple iPods cause
      pacemaker interference in 50% of their patients, with over-sensing in 20% of patients,
      telemetry interference in 29% of patients and pacemaker inhibition in 1.2% of patients. The
      mean age for their sample was 76.1 years +/- 8.6 years. We anticipate that a higher
      proportion of teenagers and children who have pacemakers use portable MP3 players than in the
      elderly adult population.We will include the first 100 patients with pacemakers and ICDs who
      consent for the prospective observational study a single tertiary care center. We intend to
      conduct a descriptive study, tabulating the number of times that a pacemaker or ICD has
      changes in the sensing thresholds, pacing thresholds, telemetry interference or pacemaker
      inhibition when exposed to a series of portable MP3 players at various distances. In
      addition, we will describe the nature and quantitative differences of those changes.
    

Detailed description: 
      Since pacemakers and implantable cardioverter defibrillators (ICDs) have been used, there
      have been questions about what external sources interference could alter their functioning or
      event recording properties. Because these devices are often intended to be life-saving, their
      proper functioning is of critical importance.

      The literature documents a number of common sources of possible interference. Interference
      with MRI and electrocautery have been observed (1, 2). Outside the hospital, store security
      devices and personal digital assistants (PDAs) have been evaluated (3, 4). In 1997, Hayes et
      al published a randomized, prospective trial concluding that cellular telephones impacted the
      functioning of pacemakers, but that they did not seem to have any effect at any significant
      distance (5). They showed that a phone being used at the ear was sufficiently far away to
      prevent a health risk and recommended that phones not be put in shirt pockets or used near
      the device.

      Unlike phones, which are commonly held to the ear, music is now available via portable MP3
      players and they can be held almost anywhere. Thaker et al state that Apple iPods cause
      pacemaker interference in 50% of their patients, with over-sensing in 20% of patients,
      telemetry interference in 29% of patients and pacemaker inhibition in 1.2% of patients (6).
      The mean age for their sample was 76.1 years +/- 8.6 years. We anticipate that a higher
      proportion of teenagers and kids who have pacemakers use portable MP3 players than in the
      elderly adult population.

      Design Prospective observational study a single tertiary care center.

      Subjects

      The electrophysiology department at Children's Hospital, Boston follows a large number of
      patients with pacemakers and ICDs. Approximately 15 patients are seen each week in clinic for
      routine pacemaker evaluation.

      Entry Criteria We will include the first 100 patients with pacemakers and ICDs who consent
      for the prospective trial.

        1. Consent for participation

        2. Active pacemaker/ICD, which is functioning appropriately at the time of interrogation
           based on internal diagnostics and the judgment of an appropriate clinician
           (electrophysiology nurse, fellow and/or attending.

        3. Normally functioning leads and thresholds at the time of interrogation based on internal
           diagnostics and the judgment of an appropriate clinician (electrophysiology nurse,
           fellow and/or attending.

      Variables

      Primary Outcome Change in pacemaker sensing thresholds, pacing thresholds, telemetry
      interference or pacemaker inhibition.

      Methods

      Study investigators will first obtain informed consent from each patient or family and, where
      appropriate, assent from the child.

      At the conclusion of their routine clinic visit, each patient will have his or her pacemaker
      attached to the appropriate proprietary interrogation system for their pacemaker device. We
      will then monitor the pacemaker/ICD system while placing a series of portable music devices
      at various distances from the pacemaker/ICD system: (1) 2cm, (2) 30cm, (3) 100cm. At each
      distance the pacemaker will be re-interrogated for changes in pacemaker sensing thresholds,
      pacing thresholds, telemetry interference or pacemaker inhibition. At the end of the testing
      process, the devices will be removed from near the patient and the device will be
      interrogated again to assure that the device is at the appropriate clinical settings.

      Risks

      We believe that there are no more than minimal risks associated with this study. The
      principle intervention is the placement of a music device near the pacemaker/ICD during the
      time of pacemaker monitoring. We consider this risk to be similar to the risks encountered by
      many patients who are currently using portable music devices outside the hospital. In
      addition, we do not expect any permanent change in the pacemaker or ICD settings, thresholds
      or functioning.

      Statistical Issues

      Hypothesis Our hypothesis is that the close approximation of portable MP3 players interfere
      with the appropriate sensing and recording of pacemakers and ICDs.

      Sample Size and Power Calculations We intend to conduct a descriptive study, tabulating the
      number of times that a pacemaker or ICD has changes in the sensing thresholds, pacing
      thresholds, telemetry interference or pacemaker inhibition when exposed to a series of
      portable MP3 players at various distances. In addition, we will describe the nature and
      quantitative differences of those changes.

      Because we do not intend to do comparisons for significance against a control group, we have
      chosen 100 patients as a reasonable sample size for evaluating possible changes in
      pacemaker/ICD function.
    

Intervention name(s): MP3
Intervention type(s): Device
Intervention description(s): 4 different brands of MP3 players will be tested at 3 distances from ICD/pacemaker site in children and adults with congenital heart disease.
Observational model: Case-Crossover
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Children and adults with congenital heart disease who have an implanted pacemaker or
        defibrillator
      
Keywords: arrhythmia; pacemaker; defibrillator; electromagnetic interference