[The spectral analysis of the P wave in patients with paroxysmal atrial fibrillation].

The aim of this study is to establish if patients with paroxysmal atrial fibrillation have an abnormal spectrum of the P wave.,Thirty-five patients with previous documented atrial fibrillation were compared with a control group of 29 patients. A signal-averaged ECG was performed using an ART-1200-EPX system, and a segment covering the last 75 ms of the P wave and the next 25 mg was analyzed in each of three orthogonal leads (X, Y, Z) and in a combined one (C). The area under the spectral curve between 20 and 50 Hz was divided by the area between 0 and 20 Hz (x 100 = AR50).,Patients with paroxysmal atrial fibrillation had greater AR50 on leads Y (78.3 +/- 42.9 vs 54.4 +/- 14.8; p < 0.01) and C (82.2 +/- 52.1 vs 58.4 +/- 14.6, p < 0.05) when compared with the control group. In the subset of patients without structural heart disease AR50 in lead X was greater. The criterion "AR50 > 55 in lead Y" identified paroxysmal atrial fibrillation with a sensitivity of 77.1% and a specificity of 85%.,This method may be useful to detect patients at risk for paroxysmal atrial fibrillation.