title: Modes of initiation of paroxysmal atrial fibrillation from analysis of spontaneously occurring episodes using a 12-lead Holter monitoring system.
abstract: Although new, possibly curative radiofrequency ablation techniques for atrial fibrillation (AF) have been developed in recent years, little is known about the mechanisms of spontaneous onset of AF episodes. Using a 12-lead 24-hour Holter monitoring system, we aimed to characterize such episodes. A total of 297 spontaneous episodes of AF in 33 patients with intermittent AF (mean age of 59 +/- 11 years) were analyzed. Two hundred seventy-six episodes (93%) were initiated by atrial premature complexes (APCs), whereas 19 episodes (6.4%) were preceded by typical atrial flutter and 2 (0.7%) by atrial tachycardia. Based on 12-lead electrocardiographic criteria, the origin of ectopic beats initiating AF was classified in 230 episodes (77.5%) as being of left atrial origin, in 6 episodes (2.0%) as being of right atrial origin and in 40 episodes (13.5%) the exact location could not be determined. In 16 of 23 patients (70%) with multiple episodes of AF, ectopic beats that initiated AF were consistently monomorphic. In the 120 seconds (6.2 APCs/min for a 30-second period) before onset of AF, frequency of ectopic beats increased from 0.8 APCs/min in AF-free intervals to 4.1/min (6.2 APCs/min for a 30-second period), (p = 0.003 and p = 0.016, respectively). In 209 of 254 episodes (82%), AF onset occurred during normal sinus rate (60 to 100 beats/min). Thus, paroxysmal AF is triggered most frequently by monomorphic left APCs. In most AF episodes, the increase in the number of ectopic beats that initiated episodes of AF occurred at a normal sinus rate.
authors.affiliation: Deutsches Herzzentrum München and 1. Med. Klinik, Klinikum rechts der Isar der Technischen Universität München, München, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Kolb
authors.forename: S
authors.initials: S
authors.lastname: Nürnberger
authors.forename: G
authors.initials: G
authors.lastname: Ndrepepa
authors.forename: B
authors.initials: B
authors.lastname: Zrenner
authors.forename: A
authors.initials: A
authors.lastname: Schömig
authors.forename: C
authors.initials: C
authors.lastname: Schmitt
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology*; D002940:Circadian Rhythm; D015716:Electrocardiography, Ambulatory; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged