title: Low frequency component in systolic arterial pressure variability in patients with persistent atrial fibrillation.
abstract: Atrial fibrillation (AF) is a common arrhythmia characterized by irregular ventricular response. During AF, beat-to-beat variability of arterial pressure (AP) is increased because of continuous changes in filling time, stroke volume and contractility. Only a few studies have analyzed short-term AP variability during AF but they were mainly focused on the effects of respiration. We therefore analyzed short-term systolic (S), diastolic (D) and mean (M) AP variability by autoregressive method and an FFT-based spectral estimation (Welch periodogram) in 26 patients with persistent AF before and after restoration of sinus rhythm by electrical cardioversion. A low frequency (LF) component (central frequency 0.07+/-0.02 Hz, mean+/-standard deviation) of SAP variability was observed in 23 out of 26 patients during AF. Frequency analysis of DAP and MAP also showed a LF component with a central frequency of 0.08+/-0.03 Hz (20 patients) and 0.07+/-0.03 Hz (25 patients), respectively. After recovery of sinus rhythm, we found significant reduction in mean SAP, DAP and MAP variability in all frequency bands. Squared coherence between SAP and heart rate variability after recovery of sinus rhythm revealed a weak and strong coupling within, respectively, LF and HF frequency bands. These data indicate that in patients with AF, in spite of an absence of rhythmical oscillation in RR interval time series, it is possible to observe a LF component in SAP, DAP and MAP variability signals. These 0.1 Hz fluctuations reflect the influence of the sympathetic fibres acting on the cardiovascular system.
authors: Dipartimento Bioingegneria, Politecnico di Milano, Milano, Italy.
authors: Luca
authors: L
authors: Mainardi
authors: Valentina
authors: V
authors: Corino
authors: Sebastiano
authors: S
authors: Belletti
authors: Paolo
authors: P
authors: Terranova
authors: Federico
authors: F
authors: Lombardi
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000503:physiopathology; D001281:Atrial Fibrillation / Q000503:physiopathology*; D017704:Baroreflex / Q000502:physiology; D001683:Biological Clocks / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D003971:Diastole / Q000502:physiology*; D004562:Electrocardiography; D006321:Heart / Q000294:innervation / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted; D013564:Sympathetic Nervous System / Q000503:physiopathology; D013599:Systole / Q000502:physiology*