FREQUENCY-DOMAIN AND TIME-DOMAIN ANALYSIS OF P-WAVE IN PATIENTS WITH PAROXYSMAL ATRIAL-FIBRILLATION

We investigated the usefulness of the time- and frequency-domain analy sis of the P wave triggered signal-averaged ECG (P-SAECG) for detectin g patients with paroxysmal atrial fibrillation (Paf). In previous stud ies, the usefulness of the time domain of the P-SAECG to detect patien ts with Paf was described but that of the frequency domain is unknown. We analyzed the P-SAECG in the time and frequency domain in 23 patien ts with Paf and 19 controls. The 32-unipolar chest lead ECGs and the s tandard bipolar limb lead ECGs were obtained. The time-domain analysis showed that the filtered P duration (fPd) was significantly longer (P < 0.01) in patients with Paf than controls: the predictive accuracy o f Paf with fPd > 120 ms was 69%. The frequency domain analysis showed that the area ratio of power spectrum area of 0-20 Hz to 20-100 Hz (AR 20) was significantly higher (P < 0.01) and the magnitude ratio at 30 Hz (%Mag.30) calculated by dividing the magnitude at 30 Hz by the maxi mal magnitude was significantly (P < 0.01) lower in patients with Paf than controls in the left lateral chest leads. The predictive accuracy of Paf with AR20 greater than or equal to 1.5 and that with %Mag.30 < 40% was 83% and 73%, respectively. Our results indicate that the freq uency-domain analysis of P craves in lateral leads is useful as is the time-domain analysis to detect patients with Paf. The AR20 greater th an or equal to 1.5 and %Mag.30 < 40% provides accurate predictability of Paf.