Long-term characterization of persistent atrial fibrillation: wave morphology, frequency, and irregularity analysis

Abstract:
Short-term properties of atrial fibrillation (AF) frequency, f-wave morphology, and irregularity parameters have been thoroughly studied, but not long-term properties. In the present work, f-wave morphology is characterized by principal component analysis, introducing a novel temporal parameter defined by the cumulative normalized variance of the three largest principal components . Based on 7-day recordings from nine patients with stable chronic heart failure and persistent AF, long-term properties were studied in terms of , AF frequency, and sample entropy . The main result of the present study is that detection of circadian rhythms depends on the parameter considered: rhythms were found in six and five (AF frequency) patients, but not always in the same patient. Another important result is that circadian rhythms detected in 7-day recordings could not always be detected in 24-h periods, thus shedding new light on the results in previous studies which all were based on 24-h recordings. Infradian rhythms were found in four and one (AF frequency) patients.