Analysis of P-wave Changes for Prediction of Atrial Fibrillation Episodes

Cristina Moreno1, Aleksei Savelev2, Pyotr Platonov3, Pablo Laguna1, Juan Pablo Martínez4
1Zaragoza University, 2St. Petersburg State University, 3Lund University, 4jpmart@unizar.es


Abstract

Introduction: Non-invasive markers of predisposition to atrial fibrillation (AF) can help to early AF detection and treatment. We focused on the analysis of ECG signals in patients with paroxysmal AF. We hypothesized that, in sinus rhythm, the P wave widens, becomes more rugose and with higher complexity in the vicinity of an AF episode.

Methods: We applied principal and periodic component analysis (PCA and πCA) as lineal spatial transformations and beat averaging to characterize the P wave in 5-minute segments in sinus rhythm. These segments were selected at 60, 30 and 5 min before an AF episodes, thus studying the evolution of the P wave features in the minutes previous to AF. The studied features were: power of the i-th transform component, PiΨ , relative power of the second-to-first component, P2Ψ,r , relative power of thirdto-first plus second component, P3Ψ,r and a measure of rugosity, the power of the P wave after high-pass filtering with a 30 Hz cut-off frequency, PiΨ,HF, i∈{1, 2, 3}.Ψ∈{PCA, πCA}, as well as the P wave duration in the first principal pal and periodic component DmnPCA.

Results: P2PCA increased as the AF episode approached from 60 to 30 min (from 45.3 to 47.6, p= 0.007) and P2πCA decreased from 30 to 5 min (from 35.8 to 32.2, p= 0.012). Moreover DmnPCA increased from 60 to 5 min (from 116.7 to 120.9, p= 0.005) and DmnπCA also increased from 60 to 30 min (from 115.1 to 116.7, p= 0.005) and from 60 to 5 min (from 115.1 to 118.3, p= 0.011).

No significant differences were found in the relative power and highfrequency power.

Conclusion: P wave spatio-temporal features showed significant changes prior to the onset of AF episodes in PxAF, showing a more complex structure, reducing its periodicity, and enlarging its duration as AF episodes approached.