title: Electrophysiological characteristics associated with symptoms in pacemaker patients with paroxysmal atrial fibrillation.
abstract: OBJECTIVE
  The purpose of this study is to identify the electrophysiological factors affecting symptoms in paroxysmal atrial fibrillation (PAF) using patients with paroxysmal atrial fibrillation and pacemakers with advanced atrial fibrillation (AF) diagnostics.
  
  
  METHODS
  Seventy-nine patients (age 71.0 +/- 8.2, 54.4% male) with symptomatic PAF and AF burden of 1% to 50% with DDDRP pacemakers implanted were assessed for 6 months. Patients recorded symptom onset and duration and these were correlated with device-derived electrophysiological data.
  
  
  RESULTS
  Of 2,638 AF episodes, 333 were symptomatic and 2,305 asymptomatic, with 194 non-atrial tachyarrhythmia symptomatic episodes giving a sensitivity of 12.6% and a positive predictive value of 63.2% for specific AF symptoms. Symptomatic AF episodes were 3.8 times more common diurnally than nocturnally (p < 0.001). Diurnally, symptomatic AF was significantly associated with a shorter AF cycle length (CL; p = 0.04), faster ventricular rate (p = 0.004), shorter PR interval (p < 0.001), faster preceding heart rate (p = 0.001) and increased early recurrence of AF (p < 0.04). Nocturnally, a significantly longer AF CL (p = 0.04) and PR interval (p < 0.001) prior to AF onset predicted symptomatic AF.
  
  
  CONCLUSIONS
  Symptoms in PAF are predicted by changes in AF episode duration, ventricular rate during AF, preceding sinus heart rate, AV nodal conduction and AF cycle length but not ventricular irregularity. Excess diurnal sympathetic tone and excess nocturnal vagal tone predispose to symptomatic PAF. These findings may have relevance for therapies for symptom control of PAF.
authors.affiliation: Department of Cardiology, Eastbourne Hospital, East Sussex Hospitals NHS Trust, Kings Drive, Eastbourne, BN21 2UD, UK. johnsilberbauer@lycos.com
authors.forename: John
authors.initials: J
authors.lastname: Silberbauer
authors.forename: Rick A
authors.initials: RA
authors.lastname: Veasey
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Cheek
authors.forename: Nadeem
authors.initials: N
authors.lastname: Maddekar
authors.forename: Neil
authors.initials: N
authors.lastname: Sulke
mesh_terms: D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control*; D002304:Cardiac Pacing, Artificial / Q000706:statistics & numerical data*; D015716:Electrocardiography, Ambulatory / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D006113:United Kingdom / Q000453:epidemiology