Spectrotemporal and spectral turbulence analysis of the signal-averaged P wave in paroxysmal atrial fibrillation

Abstract

Patients with paroxysmal atrial fibrillation (AF) have greater overall P wave magnitude than control subjects, but the temporal localization of the increased energy is unknown. P wave spectral turbulence has not been investigated in such patients, and the optimum methodology for studying P wave signals has not been defined. This study, therefore, applied both spectrotemporal and spectral turbulence analyses to the signal-averaged P waves of patients with paroxysmal AF and to representative control subjects. Group A, 58 persons without cardiopulmonary disease (24 patients with paroxysmal AF, 34 control subjects), and group B, 57 with such disease (31 patients with paroxysmal AF, 26 control subjects), were studied. Spectral analysis was performed on a windowed 64-ms data segment that was advanced through the P wave in 2-ms steps. Spectral turbulence was measured from differentiated 24-ms data segments, by either cross-correlation between adjacent spectra, or differentiation of adjacent spectral coefficients over time (SV, spectral velocity). Patients had greater maximum P wave energy than control subjects, between 80–150 Hz for group A (means, 0.9 vs 0.7 μV 2·s), and 20–150 Hz for group B (means, 22.4 vs 16.3 μV 2·s). Spectral velocity was greater in patients with paroxysmal AF than in control subjects in both groups (group A: Peak SV, 11.6 vs 7.4 μV 2 and group B: Peak SV, 12.0 vs 7.6 μV 2). Increased energy and SV were reported in the central P wave. Spectrotemporal analysis suggested abnormal atrial activation in the central P wave associated with paroxysmal AF. A localized abnormality in atrial electrophysiology may cause the electrogenesis of the arrhythmia