Circadian distribution of paroxysmal atrial fibrillation in patients with and without structural heart disease in untreated state.
BACKGROUND
This study aimed to compare the circadian distribution of the onset, maintenance and termination of paroxysmal atrial fibrillation (PAF) between structural and non-structural heart diseases (SHD and NSHD, respectively) in the untreated state.


METHODS
We included 217 patients with 338 PAF (79 SHD patients with 131 episodes; 138 NSHD patients with 207 episodes). The probabilities for the onset, maintenance and termination of PAF for each hour were analyzed using Holter monitoring data and harmonic models being fitted into a cosinusoidal function.


RESULTS
The SHD group had a triphasic circadian pattern at the onset with higher peaks at midnight, in the early morning and in the late afternoon (p < 0.05), whereas the NSHD group showed a single peak at midnight (p < 0.01). The probability of maintenance revealed a single peak during midnight (SHD, p < 0.0001; NHD, p < 0.01). The termination showed a peak at noon in the SHD group (p < 0.05), whereas there was a double peak at 10:00 am and 8:00 pm in the NSHD group (p=0.06). RR intervals just after the PAF onset showed marked shortening in the daytime initiation PAF as compared to the nighttime initiation PAF in both SHD and NSHD groups (p < 0.01).


CONCLUSIONS
These observations suggest that the SHD group has very complex onset hours, whereas the NSHD group shows complex termination hours. Reflexly accelerated sympathetic tone just after the PAF onset is suggested in the daytime initiation PAF.
Deguchi
Yoshiaki
Y
Department of Cardiology, Internal Medicine, School of Medicine, Tokai University, Isehara, Japan. deguchi@tc4.so-net.ne.jp
Amino
Mari
M
Adachi
Kumiko
K
Matsuzaki
Atsushi
A
Iwata
Osamu
O
Yoshioka
Koichiro
K
Watanabe
Eiichi
E
Tanabe
Teruhisa
T
D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology*; D016009:Chi-Square Distribution; D002940:Circadian Rhythm; D015716:Electrocardiography, Ambulatory; D005260:Female; D006331:Heart Diseases / Q000503:physiopathology; D006801:Humans; D016018:Least-Squares Analysis; D008297:Male; D008875:Middle Aged