Anagrafe della ricerca

Atrial fibrillation (AF), characterized by an irregular heart rhythm, is the most common cardiac arrhythmia, counting nearly 60 million prevalent cases worldwide in 2019 and with epidemiological projections foreseeing a further rise during the next decades. Dementia is a progressive neurological degeneration leading to decline in memory, reasoning, communication, and capacity to carry out daily activities, which currently affects more than 50 million people worldwide and with 150 million cases estimated in 2050. Both diseases share several common risk factors, many of which are modifiable, except for age and genetic factors. Through a constellation of potential underlying hemodynamic mechanisms - such as silent microembolic cerebral infarctions, altered cerebral blood flow, hypoperfusion and microbleeds - there is growing evidence that AF is independently associated with an increased risk of dementia and cognitive impairment, even in the absence of clinical strokes. However, causality mechanisms have not been established yet, and the impact of AF treatments on dementia development is far from being clear. Among the possible contributors, the hypothesis of an altered cerebral blood flow due to the AF irregular beating is the most intriguing and the least investigated. The complex interplay between wave propagation in a network of tapered viscoelastic vessels with different size and the irregular pulsatile flow makes AF effects on the brain microcirculation presently unknown. In fact, currently adopted clinical techniques to assess cerebral hemodynamics in vivo, such as transcranial Doppler and magnetic resonance imaging (MRI), lack the resolving power to provide insights on the deep cerebral regions. The present interdisciplinary Project involves two Units (Polito and Unito) and proposes an integrated and personalized in vivo-in silico framework, which combines an innovative cerebral hemodynamic beat-to-beat monitoring at the microcirculation level, with a cutting-edge multiscale computational model of the whole cardiovascular system. This approach will be carried out on a population of about 60-80 AF patients undergoing electrical cardioversion (ECV), in order to evaluate the impact of sinus rhythm (SR) restoration on AF-induced altered cerebral microvascular hemodynamics. The main goal is to understand and quantify mechanistic AF-induced effects on the cerebral circulation underlying the association between AF and cognitive decline. Thus, our research proposal aims to contribute at filling the gaps in the pathophysiological knowledge of the cerebral hemodynamics during AF and providing scientific evidence to improve clinical AF management in order to reduce the impact on cerebral circulation. In this respect, a delay of the onset of dementia by just few years would have huge socio-economic implications, in terms of the patient’s quality of life and burden of health care costs.