Heart rate turbulence after atrial premature complexes depends on coupling interval and atrioventricular nodal conduction.
BACKGROUND
Positive Turbulence onset (TO) after atrial premature complexes (APCs) was found temporally related to spontaneous episodes of atrial fibrillation. This study tested the hypothesis that heart rate turbulence (HRT) after APCs is influenced by APC prematurity independently of the prematurity of conducted ventricular complexes.


METHODS
We studied 33 patients (mean age = 58 +/- 16 years, 19 men), 11 of whom had structural heart disease, who were referred for electrophysiological studies of supraventricular or ventricular arrhythmias. Sequences of single right atrial extrastimuli were delivered with coupling intervals adjusted to reach 60% prematurity of conducted ventricular complexes. Descriptors of HRT were compared between patients with slow versus fast atrioventricular (AV) conduction of APCs.


RESULTS
The early RR interval dynamics after APCs was prominently modulated by the suppression of sinus node automaticity by the direct effect of APCs. This effect was significantly greater after earlier APCs with longer AV conduction times than after later coupled APCs with shorter AV conduction times.


CONCLUSIONS
The early phase of HRT is strongly influenced by the coupling interval of APCs, independently of the prematurity of conducted ventricular complexes. Consequently, the more positive TO preceding spontaneous atrial fibrillation episodes might be an epiphenomenon of incidental short-coupled APCs with delayed AV conduction, likely to trigger atrial fibrillation.
Wichterle
Dan
D
2nd Department of Internal Medicine, 1st Medical School, Charles University, Prague, Czech Republic. wichterle@hotmail.com
Bulkova
Veronika
V
Fikar
Miroslav
M
Havranek
Stepan
S
Stovicek
Petr
P
D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology*; D018880:Atrial Premature Complexes / Q000503:physiopathology*; D001283:Atrioventricular Node / Q000503:physiopathology; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged