Interatrial conduction in patients with paroxysmal atrial fibrillation and in healthy subjects.
BACKGROUND
Altered atrial conduction is linked to susceptibility to atrial fibrillation (AF). Whether signal propagation to left atrium (LA) during sinus rhythm differs between patients with paroxysmal lone AF and healthy subjects is not known.


METHODS
In 107 patients with lone paroxysmal AF (age 45±12 years) and 94 controls 99-channel magnetocardiography (MCG) was recorded over anterior chest. The duration of the atrial wave (Pd) and the MCG maps over time intervals corresponding to early and later LA activations were determined. Based on magnetic field orientations in LA maps, MCG atrial waves were classified into 3 types which are related to distinct interatrial conduction routes: Type 1 to Bachmann bundle, Type 2 to margin of fossa ovalis or multisite, and Type 3 to coronary sinus ostial connections.


RESULTS
Pd was longer in AF patients than in controls (112±13 vs. 104±13; p<0.001), which was most obvious in Type 1 wave (109±12 vs. 102±11 ms, p=0.003). The distribution of the atrial wave types differed between AF patients and controls: Type 1 occurred in 67% and Type 2 in 20% of controls whereas Type 1 occurred in 54% and Type 2 in 42% of AF patients, p<0.01 for difference.


CONCLUSIONS
Susceptibility to paroxysmal lone AF is associated with propagation of atrial signal to LA via margin of fossa ovalis or multiple pathways. When conduction occurs via Bachmann bundle, it is related with prolonged atrial activation. Thus altered and alternative conduction pathways may contribute to pathogenesis of lone AF.
Jurkko
Raija
R
Department of Cardiology, Helsinki University Central Hospital, Helsinki, Finland. raija.jurkko@2me.fi
Mäntynen
Ville
V
Lehto
Mika
M
Tapanainen
Jari M
JM
Montonen
Juha
J
Parikka
Hannu
H
Toivonen
Lauri
L
D000328:Adult; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology*; D054326:Coronary Sinus / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D053798:Magnetocardiography; D008297:Male; D008875:Middle Aged; D012849:Sinoatrial Node / Q000502:physiology