  Atrial fibrillation (AF) is the most common form of arrhythmia with
accelerated and irregular heart rate (HR), leading to both heart failure and
stroke and being responsible for an increase in cardiovascular morbidity and
mortality. In spite of its importance, the direct effects of AF on the arterial
hemodynamic patterns are not completely known to date. Based on a multiscale
modelling approach, the proposed work investigates the effects of AF on the
local arterial fluid dynamics. AF and normal sinus rhythm (NSR) conditions are
simulated extracting 2000 $\mathrm{RR}$ heartbeats and comparing the most
relevant cardiac and vascular parameters at the same HR (75 bpm). Present
outcomes evidence that the arterial system is not able to completely absorb the
AF-induced variability, which can be even amplified towards the peripheral
circulation. AF is also able to locally alter the wave dynamics, by modifying
the interplay between forward and backward signals. The sole heart rhythm
variation (i.e., from NSR to AF) promotes an alteration of the regular dynamics
at the arterial level which, in terms of pressure and peripheral perfusion,
suggests a modification of the physiological phenomena ruled by periodicity
(e.g., regular organ perfusion)and a possible vascular dysfunction due to the
prolonged exposure to irregular and extreme values. The present study
represents a first modeling approach to characterize the variability of
arterial hemodynamics in presence of AF, which surely deserves further clinical
investigation.
