title: Demographic and Clinical Characteristics to Predict Paroxysmal Atrial Fibrillation: Insights from an Implantable Loop Recorder Population.
abstract: BACKGROUND
  There is growing interest in detecting paroxysmal atrial fibrillation (PAF) to identify patients at high risk of thromboembolic stroke. The implantable loop recorder (ILR) is emerging as a powerful new tool in the diagnosis of PAF. Widespread implantation has significant cost implications and their use must be targeted at those patients at most risk.
  
  
  METHODS
  We retrospectively studied a population of 200 adult patients who underwent ILR implantation for the investigation of syncope or palpitations. Clinical data, baseline electrocardiogram (ECG) characteristics, and echocardiographic data were collected. All ECGs and electrograms (EGMs) were scrutinized by two blinded investigators. PAF incidence was defined as episodes lasting >30 seconds on EGMs recorded in ILR memory.
  
  
  RESULTS
  Our ILR population consists of 200 patients, 111 (56%) male, with a mean age of 61.4 years (range 19-95). PAF was detected in 42 patients. The following factors were significant predictors of PAF by multivariate logistic regression analysis: cigarette smoking (odds ratio [OR] = 3.73, 95% confidence interval [CI] = 1.40-10.24, P = 0.009) and incomplete right bundle branch block (IRBBB; OR = 9.04, 95% CI = 2.51-34.64, P = 0.00088). Significant differences included incidence of IRBBB (P = 0.012), cigarette smoking (P = 0.026), hypercholesterolemia (P = 0.015), age (P = 0.002), estimated glomerular filtration rate (P = 0.031), left atrial volume (P = 0.019), and PR interval (P = 0.031). The PAF group had significantly higher CHA2 DS2 -VASc scores (P = 0.01).
  
  
  CONCLUSIONS
  Our study reports predictive factors for PAF in an ILR population. We suggest that cigarette smoking and IRBBB are independently associated with paroxysmal AF in patients presenting with palpitations or syncope.
authors.affiliation: Cardiology Department, Bristol Heart Institute, University Hospitals Bristol NHS Foundation Trust, Bristol, UK.
authors.forename: Antonio
authors.initials: A
authors.lastname: Frontera
authors.affiliation: Cardiology Department, Bristol Heart Institute, University Hospitals Bristol NHS Foundation Trust, Bristol, UK.
authors.forename: Alexander
authors.initials: A
authors.lastname: Carpenter
authors.affiliation: Cardiology Department, Bristol Heart Institute, University Hospitals Bristol NHS Foundation Trust, Bristol, UK.
authors.forename: Nauman
authors.initials: N
authors.lastname: Ahmed
authors.affiliation: Mathematical Sciences Department, University of Bath, Bath, UK.
authors.forename: Matteo
authors.initials: M
authors.lastname: Fasiolo
authors.affiliation: Cardiology Department, Bristol Heart Institute, University Hospitals Bristol NHS Foundation Trust, Bristol, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Nelson
authors.affiliation: Cardiology Department, Bristol Heart Institute, University Hospitals Bristol NHS Foundation Trust, Bristol, UK.
authors.forename: Ihab
authors.initials: I
authors.lastname: Diab
authors.affiliation: Cardiology Department, Bristol Heart Institute, University Hospitals Bristol NHS Foundation Trust, Bristol, UK.
authors.forename: Tim
authors.initials: T
authors.lastname: Cripps
authors.affiliation: Cardiology Department, Bristol Heart Institute, University Hospitals Bristol NHS Foundation Trust, Bristol, UK.
authors.forename: Glyn
authors.initials: G
authors.lastname: Thomas
authors.affiliation: Cardiology Department, Bristol Heart Institute, University Hospitals Bristol NHS Foundation Trust, Bristol, UK.
authors.forename: Edward
authors.initials: E
authors.lastname: Duncan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000453:epidemiology*; D002037:Bundle-Branch Block / Q000175:diagnosis / Q000453:epidemiology*; D015897:Comorbidity; D003936:Diagnosis, Computer-Assisted / Q000379:methods / Q000706:statistics & numerical data; D015716:Electrocardiography, Ambulatory / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D016247:Information Storage and Retrieval / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012907:Smoking / Q000453:epidemiology*; D006113:United Kingdom / Q000453:epidemiology
keywords: cryptogenic stroke; implantable loop recorder; paroxysmal atrial fibrillation; right bundle branch block