title: Detection of atrial high-rate events by continuous home monitoring: clinical significance in the heart failure-cardiac resynchronization therapy population.
abstract: OBJECTIVE
  Uncertainty exists over the importance of device-detected short-duration atrial arrhythmias. Continuous atrial diagnostics, through home monitoring (HM) technology (BIOTRONIK, Berlin, Germany), provides a unique opportunity to assess frequency and quantity of atrial fibrillation (AF) episodes defined as atrial high-rate events (AHRE).
  
  
  RESULTS
  Prospective data from 560 heart failure (HF) patients (age 67 ± 10 years, median ejection fraction 27%) patients with a cardiac resynchronization therapy (CRT) device capable of HM from two multi-centre studies were analysed. Atrial high-rate events burden was defined as the duration of mode switch in a 24-h period with atrial rates of >180 beats for at least 1% or total of 14 min per day. The primary endpoint was incidence of a thromboembolic (TE) event. Secondary endpoints were cardiovascular death, hospitalization because of AF, or worsening HF. Over a median 370-day follow-up AHRE occurred in 40% of patients with 11 (2%) patients developing TE complications and mortality rate of 4.3% (24 deaths, 16 with cardiovascular aetiology). Compared with patients without detected AHRE, patients with detected AHRE>3.8 h over a day were nine times more likely to develop TE complications (P= 0.006). The majority of patients (73%) did not show a temporal association with the detected atrial episode and their adverse event, with a mean interval of 46.7 ± 71.9 days (range 0-194) before the TE complication.
  
  
  CONCLUSIONS
  In a high-risk cohort of HF patients, device-detected atrial arrhythmias are associated with an increased incidence of TE events. A cut-off point of 3.8 h over 24 h was associated with significant increase in the event rate. Routine assessment of AHRE should be considered with other data when assessing stroke risk and considering anti-coagulation initiation and should also prompt the optimization of cardioprotective HF therapy in CRT patients.
authors.affiliation: Department of Cardiology, St George's Healthcare NHS Trust, London, UK.
authors.forename: Nesan
authors.initials: N
authors.lastname: Shanmugam
authors.forename: Annegret
authors.initials: A
authors.lastname: Boerdlein
authors.forename: Jochen
authors.initials: J
authors.lastname: Proff
authors.forename: Peter
authors.initials: P
authors.lastname: Ong
authors.forename: Oswaldo
authors.initials: O
authors.lastname: Valencia
authors.forename: Sebastian K G
authors.initials: SK
authors.lastname: Maier
authors.forename: Wolfgang R
authors.initials: WR
authors.lastname: Bauer
authors.forename: Vince
authors.initials: V
authors.lastname: Paul
authors.forename: Stefan
authors.initials: S
authors.lastname: Sack
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000178:diet therapy* / Q000401:mortality* / Q000517:prevention & control; D058406:Cardiac Resynchronization Therapy; D015331:Cohort Studies; D015716:Electrocardiography, Ambulatory / Q000706:statistics & numerical data*; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000401:mortality* / Q000517:prevention & control*; D006699:Home Care Services / Q000706:statistics & numerical data*; D006801:Humans; D038622:Internationality; D008297:Male; D015995:Prevalence; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D015996:Survival Rate