title: Comparison of continuous versus intermittent monitoring of atrial arrhythmias.
abstract: BACKGROUND
  The ability of intermittent or symptom-based monitoring to accurately identify patients with atrial tachycardia/atrial fibrillation (AT/AF) and to quantify AT/AF burden is not well established.
  
  
  OBJECTIVE
  The purpose of this study was to compare intermittent and symptom-based monitoring to continuous monitoring for (1) identification of patients with any AT/AF, (2) identification of patients with long-duration AT/AF, and (3) assessment of AT/AF burden.
  
  
  METHODS
  Data from 574 pacemaker (AT500, Medtronic) patients were analyzed retrospectively over 1 year. The device recorded the amount of AT/AF detected each day. Intermittent monitoring (annual, quarterly, and monthly 24-hour Holter; 7-day and 30-day annual long-term recordings) was simulated by analyzing data from randomly selected days within a prescribed monitoring window. Symptom-based monitoring was approximated by analyzing days when patients indicated symptoms with an external activator.
  
  
  RESULTS
  All intermittent and symptom-based monitoring resulted in significantly lower sensitivity (range 31%-71%) and negative predictive value (range 21%-39%) for identification of patients with any AT/AF (P <.001) and underestimated AT/AF burden (P <.001) compared with continuous monitoring. Sensitivity for identifying patients with long-duration episodes ranged from 23% to 58% (P <.001 vs continuous monitoring). Identification of patients with AT/AF and assessment of AT/AF burden with intermittent monitoring depended on the patient's actual AT/AF burden and improved with increasing frequency or duration of intermittent monitoring.
  
  
  CONCLUSIONS
  Intermittent and symptom-based monitoring is highly inaccurate for identifying patients with any or long-duration AT/AF and for assessing AT/AF burden. Further investigation is required to determine if full AT/AF disclosure with implantable devices is effective in reducing stroke risk and facilitating maintenance of sinus rhythm.
authors.affiliation: Medtronic Inc., Minneapolis, Minnesota. paul.david.ziegler@medtronic.com <paul.david.ziegler@medtronic.com>
authors.forename: Paul D
authors.initials: PD
authors.lastname: Ziegler
authors.forename: Jodi L
authors.initials: JL
authors.lastname: Koehler
authors.forename: Rahul
authors.initials: R
authors.lastname: Mehra
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D002304:Cardiac Pacing, Artificial; D017147:Defibrillators, Implantable; D015716:Electrocardiography, Ambulatory / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D012107:Research Design; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013617:Tachycardia, Supraventricular / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D013997:Time Factors