title: How often should we monitor for reliable detection of atrial fibrillation recurrence? Efficiency considerations and implications for study design.
abstract: OBJECTIVE
  Although atrial fibrillation (AF) recurrence is unpredictable in terms of onset and duration, current intermittent rhythm monitoring (IRM) diagnostic modalities are short-termed and discontinuous. The aim of the present study was to investigate the necessary IRM frequency required to reliably detect recurrence of various AF recurrence patterns.
  
  
  METHODS
  The rhythm histories of 647 patients (mean AF burden: 12 ± 22% of monitored time; 687 patient-years) with implantable continuous monitoring devices were reconstructed and analyzed. With the use of computationally intensive simulation, we evaluated the necessary IRM frequency to reliably detect AF recurrence of various AF phenotypes using IRM of various durations.
  
  
  RESULTS
  The IRM frequency required for reliable AF detection depends on the amount and temporal aggregation of the AF recurrence (p<0.0001) as well as the duration of the IRM (p<0.001). Reliable detection (>95% sensitivity) of AF recurrence required higher IRM frequencies (>12 24-hour; >6 7-day; >4 14-day; >3 30-day IRM per year; p<0.0001) than currently recommended. Lower IRM frequencies will under-detect AF recurrence and introduce significant bias in the evaluation of therapeutic interventions. More frequent but of shorter duration, IRMs (24-hour) are significantly more time effective (sensitivity per monitored time) than a fewer number of longer IRM durations (p<0.0001).
  
  
  CONCLUSIONS
  Reliable AF recurrence detection requires higher IRM frequencies than currently recommended. Current IRM frequency recommendations will fail to diagnose a significant proportion of patients. Shorter duration but more frequent IRM strategies are significantly more efficient than longer IRM durations.
  
  
  BACKGROUND
  Unique identifier: NCT00806689.
authors.affiliation: Department of Cardiac and Thoracic Vascular Surgery, University of Luebeck, Luebeck, Germany.
authors.forename: Efstratios I
authors.initials: EI
authors.lastname: Charitos
authors.affiliation: Medtronic Inc., Minneapolis, Minnesota, United States of America.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Ziegler
authors.affiliation: Department of Cardiac and Thoracic Vascular Surgery, University of Luebeck, Luebeck, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Stierle
authors.affiliation: Department of Mathematics, School of Mathematical and Physical Sciences, University of Sussex, Brighton, United Kingdom.
authors.forename: Derek R
authors.initials: DR
authors.lastname: Robinson
authors.affiliation: Department of Cardiac and Thoracic Vascular Surgery, University of Luebeck, Luebeck, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Graf
authors.affiliation: Department of Cardiac and Thoracic Vascular Surgery, University of Luebeck, Luebeck, Germany.
authors.forename: Hans-Hinrich
authors.initials: HH
authors.lastname: Sievers
authors.affiliation: Department of Cardiac and Thoracic Vascular Surgery, University of Luebeck, Luebeck, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Hanke
mesh_terms: D000368:Aged; D000465:Algorithms; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology*; D002309:Cardiology / Q000379:methods / Q000592:standards; D015716:Electrocardiography, Ambulatory; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods*; D010641:Phenotype; D011336:Probability; D012008:Recurrence; D012107:Research Design; D013997:Time Factors