title: Can we rely on machines? Device-detected atrial high rates correspond well with atrial arrhythmias in cardiac resynchronization recipients.
abstract: OBJECTIVE
  The aim of the study was to verify in what proportion of patients, device-detected atrial high rate (AHR) episodes are indeed atrial arrhythmias (AAs). We investigated also the reasons for inappropriate arrhythmia classification and assessed if patients with misdiagnosed arrhythmias have distinct characteristics that would help to identify them.
  
  
  RESULTS
  The study population consisted of 304 consecutive patients implanted with cardiac resynchronization therapy defibrillators (CRT-Ds) and subsequently monitored via remote monitoring for a median follow-up (FU) of 30.5 months. Intracardiac electrograms of every recorded AHR episode were assessed and classified (AA vs. no AA) by two experienced cardiologists. During FU, 14 386 episodes of AHR were recorded and classified in 176 (57.9%) patients. In 89.2% of them, these episodes were true AA (94% atrial fibrillation, 62% de novo). The reasons for AHR misdiagnosis were atrial far-field signals (89.5%) and noise (10.5%). The mean per cent of day spent in AHR (54.9 vs. 5.86%; P < 0.001) and the occurrence of periods with low CRT pacing (82.8 vs. 55%; P = 0.003) were significantly higher in AA subjects than in those with misdiagnosed AHR. Episode duration of properly detected AHRs was longer than that of misdiagnosed AHRs. Higher per cent of time spent in AHR was an independent marker of appropriate arrhythmia detection [adjusted hazard ratio (HR) 1.04; P = 0.023].
  
  
  CONCLUSIONS
  Nearly two-thirds of CRT-D patients had AHR episodes within 2.5 years after implantation. Almost 90% of AHRs were indeed AA. Misdetections were caused by far-field sensing or noise. A two-step diagnostic algorithm (>9% of time spent in AHRs and episode duration >36 s) allowed for proper detection of AA with a high hit-rate and specificity.
authors.affiliation: Department of Cardiology, Congenital Heart Disease and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Skłodowskiej-Curie 9, 41-800 Zabrze, Poland ewajczyk@op.pl.
authors.forename: Ewa
authors.initials: E
authors.lastname: Jędrzejczyk-Patej
authors.affiliation: Department of Cardiology, Congenital Heart Disease and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Skłodowskiej-Curie 9, 41-800 Zabrze, Poland.
authors.forename: Radosław
authors.initials: R
authors.lastname: Lenarczyk
authors.affiliation: Department of Cardiology, Congenital Heart Disease and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Skłodowskiej-Curie 9, 41-800 Zabrze, Poland.
authors.forename: Michał
authors.initials: M
authors.lastname: Mazurek
authors.affiliation: Department of Cardiology, Congenital Heart Disease and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Skłodowskiej-Curie 9, 41-800 Zabrze, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Liberska
authors.affiliation: Department of Cardiology, Congenital Heart Disease and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Skłodowskiej-Curie 9, 41-800 Zabrze, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Przybylska-Siedlecka
authors.affiliation: Department of Cardiology, Congenital Heart Disease and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Skłodowskiej-Curie 9, 41-800 Zabrze, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Podolecki
authors.affiliation: Department of Cardiology, Congenital Heart Disease and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Skłodowskiej-Curie 9, 41-800 Zabrze, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Kowalczyk
authors.affiliation: Department of Cardiology, Congenital Heart Disease and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Skłodowskiej-Curie 9, 41-800 Zabrze, Poland.
authors.forename: Adam
authors.initials: A
authors.lastname: Sokal
authors.affiliation: Department of Cardiology, Congenital Heart Disease and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Skłodowskiej-Curie 9, 41-800 Zabrze, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Leopold-Jadczyk
authors.affiliation: Department of Cardiology, Congenital Heart Disease and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Skłodowskiej-Curie 9, 41-800 Zabrze, Poland.
authors.forename: Oskar
authors.initials: O
authors.lastname: Kowalski
authors.affiliation: Department of Cardiology, Congenital Heart Disease and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Skłodowskiej-Curie 9, 41-800 Zabrze, Poland.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Kalarus
mesh_terms: D000368:Aged; D000465:Algorithms; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects; D058409:Cardiac Resynchronization Therapy Devices / Q000009:adverse effects; D017147:Defibrillators, Implantable / Q000009:adverse effects; D003951:Diagnostic Errors; D004554:Electric Countershock / Q000009:adverse effects / Q000295:instrumentation*; D022062:Electrophysiologic Techniques, Cardiac / Q000295:instrumentation*; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011044:Poland; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012042:Registries; D015203:Reproducibility of Results; D012307:Risk Factors; D012815:Signal Processing, Computer-Assisted; D013686:Telemetry / Q000295:instrumentation*
keywords: Atrial far-field sensing; Atrial fibrillation; Atrial high rate episode; Cardiac resynchronization therapy; Heart failure