Signal-averaged P-wave abnormalities and atrial size in patients with and without idiopathic paroxysmal atrial fibrillation.
BACKGROUND
The relation between abnormalities in the signal-averaged P wave and atrial size has not been determined in patients with paroxysmal atrial fibrillation (PAF) without structural heart disease.


METHODS
Signal-averaged electrocardiograms of P waves were recorded in 38 patients with idiopathic PAF and 34 control subjects. Filtered P-wave duration (FPD) and root-mean-square voltages for the last 20 ms of the vector magnitude were measured. Atrial volume was calculated by cine magnetic resonance imaging.


RESULTS
FPD was longer (131.7 +/- 10.9 ms vs 120.8 +/- 8.6 ms, P <.0001) and root-mean-square voltage was lower (2.89 +/- 1.29 microV vs 3.62 +/- 1.48 microV, P <.05) in the PAF group than in control subjects. However, the various atrial volumes were similar in the 2 groups. In controls, FPD was significantly correlated with left (r = 0.593, P <.0001) and total (r = 0.492, P <.005) atrial volume but not with right atrial volume. In patients with PAF, no significant correlations were found between FPD and any of the atrial volumes. Elderly patients with PAF (age > or =60 years) showed longer FPD than younger patients with PAF (139.2 +/- 9.4 ms vs 125.6 +/- 8.0 ms, P <.0001).


CONCLUSIONS
FPD is influenced by the left and total atrial volumes in the normal heart without PAF. Prolonged FPD seems to be a useful predictor of idiopathic PAF among patients without atrial enlargement, especially in the elderly.
Ishimoto
N
N
First Department of Internal Medicine, Shiga University of Medical Science, Japan. ito@belle.shiga-med.ac.jp
Ito
M
M
Kinoshita
M
M
D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology; D016275:Atrial Function / Q000502:physiology*; D002306:Cardiac Volume / Q000502:physiology; D004562:Electrocardiography / Q000295:instrumentation*; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013614:Tachycardia, Paroxysmal / Q000175:diagnosis* / Q000503:physiopathology