title: Atrial fibrillation is under-recognized in chronic heart failure: insights from a heart failure cohort treated with cardiac resynchronization therapy.
abstract: OBJECTIVE
  Atrial fibrillation (AF) is the most common sustained arrhythmia in patients with chronic heart failure (CHF). Under-detection of asymptomatic paroxysmal AF (PAF) underestimates the true burden of AF in patients with CHF. We retrospectively studied the prevalence of asymptomatic PAF in 162 CHF patients through analysis of cardiac resynchronization therapy (CRT) device downloads to determine whether these episodes are associated with adverse outcomes.
  
  
  RESULTS
  An episode of AF was defined by mode switching on CRT devices with an atrial rate >200 for at least 30 s. Of the 101 patients thought to be persistently in sinus rhythm (SR), 27% were found to have significant paroxysms of AF, with the cumulative percentage of time in the 'mode-switch mode' (i.e. the AF burden) of 1.6 +/- 0.9%. Mortality was 19.2% in patients with newly identified PAF with hospitalization and thrombo-embolism rates of 42.3 and 2.1%, respectively, compared with mortality of 10.4% with hospitalization and thrombo-embolism rates of 41.8 and 1.9%, respectively, in patients persistently in SR (P= NS).
  
  
  CONCLUSIONS
  Analysis of data from CRT devices in a population of CHF patients with severe left ventricular dysfunction shows that a significant proportion of those perceived to be persistently in SR have undiagnosed paroxysms of AF but with relatively low burden. These episodes appear to be associated with a trend towards increased mortality but no effects on hospitalization or thrombo-embolism rates.
authors: Manchester Heart Centre, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL, UK.
authors: Jane C
authors: JC
authors: Caldwell
authors: Hussain
authors: H
authors: Contractor
authors: Sanjiv
authors: S
authors: Petkar
authors: Razwan
authors: R
authors: Ali
authors: Bernard
authors: B
authors: Clarke
authors: Clifford J
authors: CJ
authors: Garratt
authors: Ludwig
authors: L
authors: Neyses
authors: Mamas A
authors: MA
authors: Mamas
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000453:epidemiology*; D002304:Cardiac Pacing, Artificial / Q000706:statistics & numerical data*; D015331:Cohort Studies; D015897:Comorbidity; D005188:False Negative Reactions; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control*; D006801:Humans; D015994:Incidence; D008297:Male; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D006113:United Kingdom / Q000453:epidemiology