title: Daily distribution of atrial arrhythmic episodes in sick sinus syndrome patients: implications for atrial arrhythmia monitoring.
abstract: OBJECTIVE
  Disorders such as paroxysmal atrial fibrillation (AF) and atrial tachyarrhythmias (AT) are difficult to investigate because of their intermittent, and sometimes asymptomatic, nature. The aim of this study was to investigate the daily temporal distribution of AT/AF episodes--onset and occurrence--by analysing data from 250 pacemaker-implanted, brady-tachy syndrome patients who have been enrolled in the Burden II Study.
  
  
  RESULTS
  Data were analysed accounting for the mode switch list which includes date, time, and duration of each mode switch episode. Chi-squared tests for goodness of fit were used to determine whether AT/AF episode were uniformly distributed. The population analysed in the present study suggests the occurrence of a circadian rhythm of paroxysmal AF episodes, similar to that described for other cardiovascular diseases, with clustering of events in the morning from 08:00 and (to a lesser degree) in the afternoon (03:00 to 18:00). The relative risk of AT/AF onset is 13% higher during daytime, 40% lower at night (P < 0.000001).
  
  
  CONCLUSIONS
  The use of monitoring devices based on daily electrocardiogram (ECG) recording could be optimized with these data, thus increasing the probability to detect AT/AF episodes.
authors.affiliation: Cardiology Clinic, Polytechnic University of Marche Region, 60100 Ancona, Italy. ag210572@virgilio.it
authors.forename: Alessandro
authors.initials: A
authors.lastname: Capucci
authors.forename: Giovanni
authors.initials: G
authors.lastname: Calcagnini
authors.forename: Eugenio
authors.initials: E
authors.lastname: Mattei
authors.forename: Michele
authors.initials: M
authors.lastname: Triventi
authors.forename: Pietro
authors.initials: P
authors.lastname: Bartolini
authors.forename: Gianluca
authors.initials: G
authors.lastname: Biancalana
authors.forename: Alessio
authors.initials: A
authors.lastname: Gargaro
authors.forename: Andrea
authors.initials: A
authors.lastname: Puglisi
authors.forename: Federica
authors.initials: F
authors.lastname: Censi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology*; D002940:Circadian Rhythm; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods; D012189:Retrospective Studies; D012804:Sick Sinus Syndrome / Q000150:complications / Q000503:physiopathology*; D013610:Tachycardia / Q000175:diagnosis / Q000503:physiopathology*