title: Do we need to monitor the percentage of biventricular pacing day by day?
abstract: BACKGROUND
  Incidence and clinical significance of transient, daily fluctuations of biventricular pacing percentage (CRT%) remain unknown. We assessed the value of daily remote monitoring in identifying prognostically critical burden of low CRT%.
  
  
  RESULTS
  Prospective, single-centre registry encompassed 304 consecutive heart failure patients with cardiac resynchronization therapy defibrillators (CRT-D). Patients with 24-h episodes of CRT% loss<95% were assigned to quartiles depending on cumulative time spent in low CRT%: quartile 1 (1-8days), 2 (9-20days), 3 (21-60days) and quartile 4 (>60days). During median follow-up of 35months 51,826 transmissions were analysed, including 15,029 in 208 (68.4%) patients with episodes of low CRT%. Overall, mean CRT%≥95% vs. <95% resulted in a 4-fold lower mortality (17.3 vs. 68.2%; p<0.001). Fifty-four percent of patients experienced episodes of CRT% loss, despite 85.6% having mean CRT%≥95%. Mortality was lowest in quartile 1 (7.7%), while longer periods of CRT% loss resulted in significantly higher death rates (25.0 vs. 34.6 vs. 57.7%; quartiles 2-4 respectively, p<0.001), despite mean CRT% still being ≥95% in quartiles 1-3. Cumulative low CRT% burden was the independent risk factor for death (HR 1.013; 95% CI 1.006-1.021; p<0.001). Mortality rose by 1.3 and 49% with every additional day and quartile of CRT% loss, respectively.
  
  
  CONCLUSIONS
  Daily remote monitoring allows one to detect 24-h episodes of CRT% loss<95% in over two-thirds of CRT-D recipients during median observation of 3years. Cumulative low CRT% burden (in days) independently predicts mortality before mean CRT% drop.
authors.affiliation: Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Zabrze, Poland. Electronic address: m.i.c.h.a.l@wp.pl.
authors.forename: Michał
authors.initials: M
authors.lastname: Mazurek
authors.affiliation: Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Zabrze, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Jędrzejczyk-Patej
authors.affiliation: Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Zabrze, Poland.
authors.forename: Radosław
authors.initials: R
authors.lastname: Lenarczyk
authors.affiliation: Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Zabrze, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Liberska
authors.affiliation: Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Zabrze, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Przybylska-Siedlecka
authors.affiliation: Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Zabrze, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Kozieł
authors.affiliation: Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Zabrze, Poland.
authors.forename: Stanisław
authors.initials: S
authors.lastname: Morawski
authors.affiliation: Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Zabrze, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Podolecki
authors.affiliation: Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Zabrze, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Kowalczyk
authors.affiliation: Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Zabrze, Poland.
authors.forename: Patrycja
authors.initials: P
authors.lastname: Pruszkowska
authors.affiliation: Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Zabrze, Poland.
authors.forename: Sławomir
authors.initials: S
authors.lastname: Pluta
authors.affiliation: Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Zabrze, Poland.
authors.forename: Adam
authors.initials: A
authors.lastname: Sokal
authors.affiliation: Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Zabrze, Poland.
authors.forename: Oskar
authors.initials: O
authors.lastname: Kowalski
authors.affiliation: Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Zabrze, Poland.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Kalarus
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000209:etiology; D058406:Cardiac Resynchronization Therapy / Q000379:methods / Q000706:statistics & numerical data; D004868:Equipment Failure / Q000706:statistics & numerical data*; D019544:Equipment Failure Analysis; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D006801:Humans; D015994:Incidence; D000069451:Long Term Adverse Effects / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data; D010043:Outcome and Process Assessment, Health Care; D011044:Poland / Q000453:epidemiology; D058998:Remote Sensing Technology / Q000009:adverse effects / Q000379:methods / Q000706:statistics & numerical data
keywords: Biventricular pacing; Cardiac resynchronization therapy; Heart failure; Mortality; Remote monitoring